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Proposal for semantic graph : Boost Mentors, please comment on it
by Chinmaya Poswalia 31 Mar '10

31 Mar '10

*Need For Semantic Graph* First thing I would like to mention is that semantic graph is not merely a graph with links and nodes. It’s a graph in which nodes links can be of different data types and similarly links. It's a graph of interconnected things that is machine-understandable, its meaning or "semantics" can be explicitly represented on any common database, just like its data. This is the real way to make social networks, applications, libraries and information/data open. Merely opening up their API's is just the first step. Through it, applications can start using the functions and properties written in other languages. Since the Semantic Library makes data-integration easier, it will ultimately be widely adopted and will cater most to the community. Simply put, applications that wish to access or integrate data in the modern age can more easily be done. That alone is reason enough to use this library. Summarising the above Ø Making data more accessible, connectable, and reusable across applications would be a huge benefit. Ø Ability to do more sophisticated reasoning across data. Ø Applications in which its use can directly be seen is World Wide Web. Please refer the above link for more detail. http://novaspivack.typepad.com/nova_spivacks_weblog/2007/11/defining-the-se… http://www.signosemio.com/rastier/a_graphe.asp *Project Proposal* [dog] <- (ERG) <- [bite] -> (ACC) -> [man] <---------------------- Semantic Graph Here dog, bite and man all are of different types and ERG and ACC are the relations where ERG -> *corresponds to the ergative case (the agent of an action)* ACC-> to* the accusative case (the patient of an action, the one affected by it)* I am aiming to make the first steps towards the conceptualization and formulation of Semantics Graphs for the Boost Graph Library (BGL). *1) **Node Data Structure* Node should have a container to store data and an array of functions whose scope will be limited to only process the data of its own node and attached links. These nodes can process their data individually and this functionality would be defined by the functions which user would provide through the array of functions and can transmit request for processing to another nodes through links joined to them. Nodes will also contain the pointer to all the links leaving it. *2) **Link Data Structure* Links apart from containing data it will contain some defined constants whose actions value would be provided at the start time and should. These constants would define the relation between the nodes it is connecting to. Majorly relations would include of the following types like who is the agent of action, who is the recipient of action, which is the proposed result of the action, what is the final result, what is the beneficiary action and who is the beneficent of the action, who is the comparing element and who is being compared. The following paper clearly states what semantic graph is mathematically. http://www.revue-texto.net/Parutions/Livres-E/Hebert_AS/12.Semantic-Graph.p… *3) **Algorithms For Traversal of The Graph* Here I want to state that I found a library for semantic graphs which is in the CLI library. It can be obtained at http://www.codesynthesis.com/~boris/tmp/cli/cli-0.0.2+dep.tar.bz2<http://www.codesynthesis.com/%7Eboris/tmp/cli/cli-0.0.2+dep.tar.bz2> The basic algorithm of Traversal can be used but here since the nodes and links are of different data types, this can be implemented with the help of a void pointer. Once we reaches a node, we will mark it explore and the will move to the links that leaves it. This will even provide the functionality to enable us to find a link. How knowledge will be represented and how what variables and functions need to be implemented, these issues and their solution are clearly stated in the following research paper. http://www.edmondchow.com/pubs/SS105ChowE.pdf An application of semantic sub-graph involving knowledge representation and text summarisation is given in the following paper written under Microsoft Research. http://nl.ijs.si/isjt04/zbornik/sdjt04-05leskovec.pdf Please note the fact that through this way, i think the space occupied by the graph is minimal as it only depends on the containers used by the user. We just used 3 pointers for linking the nodes.

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[concept_check] silence gcc warnings
by Jürgen Hunold 31 Mar '10

31 Mar '10

Hi ! I've started to use Boost.Accumulators and I'm getting tons of ugly warnings when compiling with optimization on. See full "warn.log" for details, This boils down to boost/concept_check.hpp 335: warning: non-static reference ‘const float& boost::UnaryFunction<boost::numeric::functional::as_max<const float, void>, float, const float&>::arg’ in class without a constructor [-Wuninitialized] when the check ist called with a reference parameter. It seems that providing a dummy constructor is sufficient to silence this. Please find a patch attached. Okay to commit ? Or are the better ideas ? Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! Ingenieurgesellschaft für * voice: ++49 511 262926 57 ! Verkehrs- und Eisenbahnwesen mbH * fax : ++49 511 262926 99 ! Lister Straße 15 * juergen.hunold(a)ivembh.de ! www.ivembh.de * * Geschäftsführer: ! Sitz des Unternehmens: Hannover * Prof. Dr.-Ing. Thomas Siefer ! Amtsgericht Hannover, HRB 56965 * PD Dr.-Ing. Alfons Radtke !

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Google Summer Of Code
by Brian Bartman 30 Mar '10

30 Mar '10

Hello my name is Brian Bartman and I am an undergraduate at Kent State University Majoring in computer science. I was interested in the bits & ints project, specifically Compressed array and Compressed vector as well as the utilities for bit mask manipulation. Could some one help me better understand the requirements of this project? I would like to draft a proposal for GSoC 2010 and wanted to better understand the project before I write a proposal.

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Re: [boost] [MSM] using irow "internal transitions" and constructorarguments for frontend ?
by Christophe Henry 30 Mar '10

30 Mar '10

Hi, >We have seen that there was a review early this year is there a boost >version where msm will be officially part of boost lib ?. I'm finishing it and hope to bring it into the 1.43. Hopefully, the newest version will be online in a few days. If you cannot wait, I can send it to you before. >Is anybody used boost::msm in a real life project is there any >measures about stability ?. I did but I'm biased ;-) Seriously, I know a few people who did and reported here and there a bug (which is usually corrected very fast) but nothing critical. I'd also be interested in live reports. >Furthermore we had the following problems during our evaluation: > >1.) in the documentation there is a section about internal transitions >using irow : I think this is in the documentation from the sandbox, not the vault. The doc in the sandbox is not up to date because I made an almost full rewrite. MSM 2.0 supports no internal transitions, but the subject was brought by Michael Caisse during the review and the coming version 2.10 has them. The sandbox version also has internal transitions and is usually up to date, except, as I said, the doc (but not for long). >2.) State machine constructor with arguments in the documentation >there is an example but we did not managed to get it working > >is this example correct in the documentation ?. The example is correct and should work but I admit I'm unsure if it was already in the 2.0. I guess not. Please try the sandbox or the coming 2.10. But thanks for telling me, I just realize I forgot this part in the new doc, so I will add it. Thanks, Christophe

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BoostCon2010 lodging - M4MW
by Robert Ramey 30 Mar '10

30 Mar '10

I'm making arrangements to attend BoostCon2010. I'm reviewing the Aspen Meadows Resort web page. Seems like a very fancy and nice setup. The rates are $159 + 10% + $18 / day for one or two persons. I expect to be going by myself as my wife considers attendance at such an event as boring beyond belief. I'm also a free lance software developer so I will be paying myself. So it would be economically advantageous for me to share this with at least one other person (The room has a capacity up to 4 persons). So anyone who want's to split this with me should let me know via private email ramey(a)rrsd.com. BTW- I'm still considering options about getting there. I haven't been on an airplane since 1995. From what I hear, it's even more unpleasant now than it was then. But it's a long drive from where I live. Anyway ... Robert Ramey

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Boost.Graph GSoC 2010
by Cezary Bartosiak 30 Mar '10

30 Mar '10

Hi, I am Cezary, a student of computer science at the Cybernetics Faculty, Military University of Technology, Warsaw. I am interested in developing the BGL. I've got an idea related to the Topology Generators. I have participated in a project concerning epidemics spreading and, as a part of the project, we have implemented several social networks generators (Barabási–Albert model for instance). I hit upon an idea to implement these algorithms apart from proposed topology generators. I know that Boost.Graph contains some algorithms for generating networks, I would like to add some extensions: 1. There is Erdős-Rényi model generator in two versions G(n, p) and G(n, m). I think I could provide some additional implementations for specific cases, I mean: a) Fast generator of sparse graphs inspired by http://www.inf.uni-konstanz.de/algo/publications/bb-eglrn-05.pdf. b) Fast generator of dense graphs, algorithm by Keith M. Briggs Mar 31, 2006 (the only implementation of this one I've seen in NetworkX library). 2. There is only Beta-model generator of Small World network in the library. I would like to add Alfa-model generator as well as Kleinberg model generator. Here are some interesting materials: http://tam.cornell.edu/tam/cms/manage/upload/SS_nature_smallworld.pdf http://www.bsos.umd.edu/socy/alan/stats/network-grad/summaries/Watts-Six%20… http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.83.381&rep=rep1&ty… 3. At the moment we've got only PLOD algorithm to generate ScaleFree networks. I could provide other ones: a) Basic generator often seen in popular libraries, for instance NetworkX. b) Generalized generator with probabilities of adding new edges and rewiring existing ones. c) Simplified models generators: A (uniform attachment) and B (no growth). Coming back to Topology Generators I would implement them for some "basic" topologies, let's say: path, star, cycle, wheel, ladder, grid, hypercube, barbell, complete, frucht and many others if time remains... I would be glad to know your opinion. Best, Cezary

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[GSoC] Advanced data structures library
by Rui Gonçalves 30 Mar '10

30 Mar '10

Hello, I'm new to this community. My name is Rui Gonçalves and I'm thinking about submitting an application to Boost in Google Summer of Code. In particular, due to my own programming interests in data structures, generic programming and abstraction layer developing in general, I would be very happy in developing an advanced data structures library. As suggested in the ideias page, it would have includes various types of heaps and queues. I haven't had time to look at all different libraries, but if there is some known data structure with implementation needed, I would not mind implementing that too. I had a look at the /boost/pending available implementations. A lot of code could be reused / ported; however, I think that the source code could be more standardized between heap implementations. I'm thinking in a STL-like implementation, like: template < class T, class Heap = binary_heap<T>, class Compare = less<T> > class priority_queue; template < class T, class Container = vector<T>, class Compare = less<T> > class fibonacci_heap; I already looked in books for some more obscure details of each algorithm, and haven't found anything excessively difficult. This seems a rather simple project (although I recognize it can take some time). Is there some convention or requirements for data structures in Boost? Is there any difficulty that I should be aware of but didn't notice, or any detail about GSoC that I should know? (I'm new to that program and I feel kind of lost). Thank you in advance for your help, Rui Gonçalves

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[MSM] using irow "internal transitions" and constructor arguments for frontend ?
by Richard Szabo 30 Mar '10

30 Mar '10

Hi All We are in a process to evaluate boost::msm 2.0 we would like to use it in our project. We were using sources from http://www.boostpro.com/vault/index.php?directory=Msm version 2.0. We have seen that there was a review early this year is there a boost version where msm will be officially part of boost lib ?. Is anybody used boost::msm in a real life project is there any measures about stability ?. Furthermore we had the following problems during our evaluation: 1.) in the documentation there is a section about internal transitions using irow : see : irow < Empty , cd_detected , &p::internal_action ,&p::internal_guard > but we did not find the irow definition in the sources ?. 2.) State machine constructor with arguments in the documentation there is an example but we did not managed to get it working is this example correct in the documentation ?. struct player_ : public msm::front::state_machine_def<player_> { player_(int some_value){…} } This is still possible, using the back-end as forwarding object: typedef msm::back::state_machine<player_ > player; player p(3); // do something with the state machine Thanks in Advance Richie & Michi

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GSOC Boost BigInt design issues
by swagat konchada 30 Mar '10

30 Mar '10

> >swagat konchada wrote: > > > > I had a look upon the BigInt code from the sandbox. It's > > entirely wrapped around GMP(linked to gmblib). > [snip] > > That is uncompatible with the Boost license, which hinders > > the distribution > > of a Boost_bigInt library which wholly is a wrapper around GMP. > > > > Keeping in view the above issues what should be our priority? > > Improving the > > wrapping around GMP for time being or Starting Boost's own version of > > BigInt. I see mixed reactions on this subject. My personal > > opinion is that > > suggested by Paul A. Bristow, i.e, of a Boost's own BigInt, > > which I think is in line with Boost's long term aspirations. > > > Rob Stewart wrote > The usual idea is that BigInt would provide expression templates and other > optimizations to avoid calling the back end engine inefficiently. That may > require an adapter layer between the user-visible BigInt API and the > computation engine, like GMP, at the back end, to insulate the API from > differences in the back end engines. (Then again, there may be nothing left > to a layer above the adapter layer; I'm not saying there must be three > layers.) > > If GMP is an optional batck end supported by BigInt, along with other back > ends, controlled by conditional compilation, then a BigInt user can choose > to use GMP if they like, but the licensing issue will be theirs and not > Boost's. > > HTH, > > _____ > Rob Stewart robert.stewart(a)sig.com > Software Engineer, Core Software using std::disclaimer; > Susquehanna International Group, LLP http://www.sig.com > > If we consider performance issues based on design, planning the BigInt architecture could be designed in two ways 1. 3 layers to allow optional binding to Boost's own bigint, GMP, or anyother bigint library, for the user during compile time. 2. 2 layers if we plan to limit Boost.Bigint's options to only itself and GMP. In a 3 layered architecture, 3 function calls would take place for each overloaded operator, whatever the option chosen by the user. Whereas in a 2 layered architecture, in which only GMP is an extra option, there is an equal probability of a user using Boost's own bigint or GMP and thus half of the times, 2 function calls are made and in the other half only 1 function call for each overloaded operator. This means doubling in the number of function calls. Though I realize most of the time is spent inside the function rather than in calling the functions, does this result in an overhead we should worry about? -- Problem is a phenomenon indicating lack of thought. Swagat Konchada

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Library dependencies and intrer-library code reuse
by Zachary Turner 30 Mar '10

30 Mar '10

There's a lot of chatter on the list recently about how to "grow" boost. I wanted to add my own idea to the pot. Due to the scope of what I describe, I don't think it's reasonable to expect everyone to be on board with it because TBH it's a lot of work, but I'm just throwing it out there, and I think that if you forget about what would be involved in actually making it happen, it actually has many highly desirable properties. But comments would be welcome. So anyway, one of the recurring questions that pops up over and over and over is that of whether or not a library should reinvent the wheel, or use some data structure / class from some other library. On one side of the fence, there's people who say that it's often ok to reinvent the wheel inside library A if it avoids introducing a dependency on boost library B. Generally, the problem is that introducing a dependency on B a) increases compile time, because often only an extremely small component of library B is needed, but the header-onlyness of most libraries causes inclusion explosion, and b) introduces logistical problems when library B is not "permitted" for use in a certain organization. This is becoming increasingly common as certain organizations begin whitelisting boost libraries that are allowed in their codebase. On the other side of the fence, there's people who say that reinventing the wheel is almost always bad. The reasons for this are obvious and I think everyone here is well aware of the issues, so I won't repeat them. Note that I'm not taking sides here, just pointing out that the argument against reinventing the wheel is well understood. Is there a way to solve *both* of these problems at the same time? I think there is. Consider the following system: 1) Library maintenance is more flexible, and not necessarily limited to only a single maintainer or a whitelisted group of maintainers. There is another thread on this topic already, so rather than debating this particular point here, it's probably better suited in the other thread. For the purposes of this post, just assume that there is *some* system, with completely unspecified parameters, where there is *some* way for people to easily get their own code into an existing library that they are not necessarily the author / maintainer of. At the very least, *other library authors* would be given a "fast track" to submitting changes to other libraries, whatever "fast track" means. 2) All libraries would be required to support both pimpl'ed and header-only implementations. I realize this is sort of a huge undertaking and requires retrofitting tons of libraries, but I think the advantages are worth it. The users end up winning in the long run, nobody ever has to have this debate again about whether or not header only libraries are good or bad. If you want header only libraries, use #include <boost/someheader.hpp>. If you want pimpl'ed libraries, use #include <boostp/someheader.hpp>. pimpled' headers only include other pimpled headers. Also it makes the system I'm describing possible. 3) The boost build process is changed to allow additional options that either: a) automatically select all libraries for external visibility, b) select a specific list of libraries for external visibility, or c) select a specific list of libraries to disable external visibility. During the build process, what is currently known as the "boost" directory (e.g. the boost folder in #include <boost/shared_ptr.hpp>), gets a different name. Perhaps it's changed to something like <boost/internal/shared_ptr.hpp>. This happens EVERYWHERE. All boost library header and source files would need to be updated to include from boost/internal. For those libraries that were selected for external visibility, a symlink is created under the boost directory inside the internal directory. On windows a directory junction is used. Note that directory junctions are supported since Windows 2000, so I don't think this is an issue. It's very easy to create them, just that people rarely do. The end result of this is the following: 1) Users notice minimal impact. The only difference, in fact, is that if they want pimpled implementations they #include <boostp/...> instead of #include <boost/...>. This means the current behavior continues to be the default. After they build boost, the build process handles all the logistics. Everything is already in the correct structure to "just work", all symlinks have been created as described in 3) above, and the user only needs to set their include path to the top level boost directory. 2) All boost libraries can use all other boost libraries with ease, regardless of whether or not an organization's policy allows use of those libraries in user code, because internally all libraries include from boost/internal. 3) Despite the fact that all these additional dependencies that a user isn't technically allowed to be using due to his organization's policy are indeed being used, compile times can be kept sane because the user has access to pimpled libraries, and pimpled libraries only depend on other pimpled libraries, which is possible since all libraries are required to support pimpled versions. So there we go. Does this work, and if not why not? Even if we agree it's a huge undertaking, is it worth it? And if not, why not? Zach

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Boost, Decoupled and Accelerated
by David Abrahams 30 Mar '10

30 Mar '10

Hi All, I know I'm not the first person to notice that, as Boost has grown, it has become harder and harder to manage, Subversion is getting slow, our issue tracker is full to overflowing, and the release process is a full-time job. For me, this situation has taken a lot of the fun out of participating. It's time to make Boost development fun again. To that end, Troy Straszheim and I have started building a system called Ryppl to decentralize development, testing, release, and installation of interdependent projects, like—but not limited to—Boost libraries. I will be holding a session **Tuesday night at BoostCon** to formally unveil this system and demonstrate it in action, and I intend to propose that Boost make the move immediately thereafter. I believe this project has the potential to change the face not only of Boost, but of open-source software in general. By the time of BoostCon, ryppl will be live, and we'll be able to use it to work on Boost. I encourage anyone who is interested in these developments to register for BoostCon immediately. If you're interested in working on development of this system, *please* send me an email; we can really use your help. Be forewarned, though: this may not operate like many other open-source projects. Given the short period of time remaining before the conference, we have little time for design discussion and debate, and we need to be maximally effective: there's simply no time to waste. You can expect me to take a “Benevolent Dictator” role, if not “For Life,” (BDFL) then at least “For the Time Being” (BDFTB). Cheers, -- Dave Abrahams Meet me at BoostCon: http://www.boostcon.com BoostPro Computing http://www.boostpro.com

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[GSoC] Generic Linked List library
by Thomas Mullaly 30 Mar '10

30 Mar '10

Hi, my name is Thomas Mullaly. I am currently an undergraduate in the Computer Science department at Kent State University and I am interested in contributing a generic linked-list library to Boost as a GSoC project and I just wanted to see if there is any interest from the Boost community about having these contributed as a library. I am implementing the linked lists project from 'Elements of Programming' (ch. 12, I think), and am trying to provide lists for both constant-time size and constant-time splice. My library currently implements a number of variations of both singly- and doubly-linked lists, and I have implemented a wrapper that adds a node count and acts as a counted list. While the basic list types are already implemented, there is still a lot of work to done on them. For my GSoC project I would like to integrate allocator support into them, clean up the existing interface, and create a generic interface to the different types of lists with the help of a mentor. By the end of my GSoC project I would like to have a functional list library to contribute to Boost. I feel that this would be a valuable library to Boost because the standards implementation limits you (depending on your library vendor) to either a constant time size() function with a linear time splice operations or constant time splice operations with a linear time size() function. With my implementations a developer will be able to pick and choose whether they want a singly or a doubly linked list, or if they want to use a counted listed instead of a non-counted list. Also their is variations in memory/runtime efficiency between the different variations of the list types which a developer will be able to choose for. Currently my list implementations make heavy use of the new features available in C++0x such as rvalue references and move semantics, but, I will be more than happy to create a backport of these for the current C++ standard so they can be included in Boost. If anyone is interested in the source code for my current list implementations I will be able to provide tarballs of them.

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[GSoC] Bits and Ints
by Gaurav Menghani 30 Mar '10

30 Mar '10

Hello, I am keen on working on the Bits and Ints project. However, I would be glad if someone could answer my queries. In the project description, the second line says: "Compressed value array and vector (like vector<bool> but also for multi-bit values)" 1) When we are talking of Compressed Value Array, are we looking at a functionality similar to the Deflater() class in Java, or something like Run Length Encoding / Delta Encoding? 2) I am also not sure if I get what is meant by "but also for multi-bit values", do you mean multi-dimensional bit-fields? 3) Can we discuss the proposal-drafts on the mailing list, even after the application time frame begins (March 29, 2010, 19:00 UTC)? Warm Regards, Gaurav Menghani

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5 Observations - My experience with the boost libraries
by Tom Brinkman 29 Mar '10

29 Mar '10

Over the past years, every project that I have been involved with has tried and then either abandoned boost or highly restricted its use. As a long time boost user, I can't tell you how much debate we've had about this. I want boost to succeed, grow and be successful. Its sad. As someone who has used boost from the beginning, and has taken far more than I have given, here are some of my observations. Many of the reasons don't have specifically to do with boost, but more have to do with a preference for one programming style versus another. I have identified 5 key issues about why boost was abandoned. 1) Boost uses exceptions. 2) Printf versus Iostream. 3) Dependencies. 4) Research Projects 5) Macros 1) Boost uses exceptions. This issue is best illustrated when you want to just do something as simple as converting a "string" to an "int". boost::numeric_cast throws an exception, which forces you to wrap it into a try-catch block. The seemingly trivial issue of how to handle exceptions causes endless grief. It seems that developers still prefer "C" style casts. The prevailing view on projects that I have worked on is that C++ exception handling should optional and not required. int value = 0; try {value = boost::numeric_cast<int>("3.00");}catch (...){} versus int value = atoi("3.00"); I think the lesson is that there is no correct answer here. As most "C++" projects use some "C" libraries, you will need to be flexible in your approach to exception handling. A pure "C++" approach of try-catch blocks is not practical. As boost libraries tend to throw exceptions, it forces you to put try-catch blocks all over your code. Many developers will simply ignore this issue and end up with lots of code that is not exception safe. Small issue, but is undoubtably a source of a huge amount of problems. 2) Printf versus Iostream. Most developers still prefer "printf" over "iostream" style "api's". Unfortunately, Boost libraries have long ago adopted "iostream", as the preferred API style. This issue has been the source of many hours of needless debate. Pure C++ developers seem to have a aversion to "printf" style arguments. As there are very few pure C++ projects (if any), I dont hear about this as much as I once did. Most C/C++ developers prefer a printf style api. Boost needs to start providing printf style api's. Boost needs to be more practical. By not also providing printf style api's, boost is not meeting the needs of developers. Iostream may be preferable for purely academic reasons, but for practical reason, "printf" is the api style that is universally adopted. Is it boosts goal to meet only the needs of a small subset of its c++ users? If that is the goal, than it needs be clearly stated as such. As most developers have adopted a combined C/C++ style of development, a pure academic C++ style syntax is not practical for every day use. Boost needs to look at what the popular api styles are and adopt them and not be so dogamtic about its style of so-called pure "C++". 3) Dependencies. Everyone has a few favourite boost libraries. Unfortunately, because of confusing dependencies between them, its practically impossible to isolate the ones you want from from the ones you don't. What does this mean? Well, it requires the leads of a given project to create a policy about which boost libraries are approved and which ones aren't. Because of the difficulty of doing this, after a while, its can become eaiser to just say "screw it". We won't use boost at all. This issue may seem trivial, but it is the cause endless hourse of grief. It seems that once you add boost to your project, some developers feel that you should be able to use any part of boost. For obvious reasons, project leads prefer to have control over which libraries are used in a given project. Few will just give blanket approval to all boost libraries. The way boost was developed makes this practically impossible. Boost needs to advertise itself correctly and not pretend to be something its not. Its simple a place for promising research libraries to live, to get some exposure, and possibly be adopted by the larger C/C++ community. Currently, boost provides the best place to do that, but it needs to be honest with its users. 4) Many boost libraries seem more like they research projects. The prevailing view is that boost libraries push the envelope of what is possible. This is universally considered a good thing and it is always interesting to see what the best and brightest are up too. Unfortunately, boost pretends to be something else. It pretends to be a collection of libraries that meet your day to day needs. Experience proves otherwise. The practical needs of large scale active projects are in conflict. Boost is very dogmatic and encourages a particalular style of development, which is very template based. In the right hands, a heavy templated based project can work. In my experience, however, it takes many many iterations to get a template based designed library correct and usable. Many more iterations, in fact, than the equivalent non-template design. It is soo difficult, that I am very reluctant to use others template based libraries. I approach them with fear. That being said, boost::mpl and boost::spririt are wonderful accomplishments and I use them regularly. 5) Macros. Need I say more. The core boost libraries are full of macros. So much in fact, that close examination makes many of them practically unmaintainable. I know there are practical reasons to use them. The main reason being compiler inadequacies. However, many developers question the value of a cutting-edge template library that is full of macros. What is the point of having the source code, when it take an experienced developer many weeks to understand what the library is doing underneath? What is the practical value of a library that can only be maintained by the original developer(s)? This issue has surprised many, but has comes up often. If it takes more than a day to examine a libraries source code and have some idea what its doing, its very dangerous to use. This issue will cause many to avoid complex templated macro-style boost libraries. Tom Brinkman

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GSOC BigInt Licensing Issues
by swagat konchada 29 Mar '10

29 Mar '10

I had a look upon the BigInt code from the sandbox. It's entirely wrapped around GMP(linked to gmblib). #inlcude<gmp.h> #ifdef BOOST_BIGINT_HAS_GMP_SUPPORT #include <boost/bigint/bigint_gmp.hpp> namespace boost { typedef bigint_base<detail::bigint_gmp_implementation> bigint; } I also read the LGPLicense which the GMP library carries with itself. This is my inference : The bigint code(from the boost sandbox) could be addressed in LGPL terms as "An Application" : which LGPL defines "as any work that makes use of an interface provided by the Library, but which is not otherwise based on the Library.", since it just uses the gmp.h interface and linking to gmplib. So the combined work, application and GMP, should be conveyed with a GNU GPL license. The Boost License allows skipping the copyright notices if only it's executables are used, unlike the LGPL which requires to distribute it's license. And there are even restrictions on "conveying the object code under terms of your(Boost') choice", in addition to other restrictions. That is uncompatible with the Boost license, which hinders the distribution of a Boost_bigInt library which wholly is a wrapper around GMP. Keeping in view the above issues what should be our priority? Improving the wrapping around GMP for time being or Starting Boost's own version of BigInt. I see mixed reactions on this subject. My personal opinion is that suggested by Paul A. Bristow, i.e, of a Boost's own BigInt, which I think is in line with Boost's long term aspirations. I hope my understanding of the issue is correct. I would be grateful to receive suggestions and comments which would help my GSOC proposal for BigInt, which I plan to submit as early as possible. -- Problem is a phenomenon indicating lack of thought. Swagat Konchada

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[GSoC]
by Andrew Sutton 29 Mar '10

29 Mar '10

Just a reminder, Google Summer of Code student applications can now be submitted here [1]. The deadline for submitting an application is Apr 9. Ideas for some student projects and other information about the program can be found here [2]. Andrew Sutton andrew.n.sutton(a)gmail.com [1] http://socghop.appspot.com/ [2] https://svn.boost.org/trac/boost/wiki/SoC2010

1 0

[GSoC] Mentors group
by Andrew Sutton 29 Mar '10

29 Mar '10

All, If you are registered as a mentor for GSoC 2010, I'm going to invite you to the mentor's group/mailing list here [1]. This will be used to discuss student proposals and vote on the set of final projects for Boost. If you are already registered, then you probably won't be receiving a new invitation. This list is historically low-traffic. If you have any questions or comments, please let me know. Andrew Sutton andrew.n.sutton(a)gmail.com [1] http://groups.google.com/group/boost-gsoc-mentors

1 0

Observations - moving from boost_1_39_0 to boost_1_42_0
by Jeff Flinn 29 Mar '10

29 Mar '10

Lets not lose site of what boost is doing right. I've just updated to boost_1_42_0 from boost_1_39_0 for XCode and MSVC. 1. All but 2 previous workarounds for compiler warnings are non longer needed 2. One wrinkle in build for xcode - now require --layout=versioned 3. MSVC (distributed) build of my app using boost completes 20% faster 4. My app's full test suite runs 10% faster Thanks to all who've made this happen! If your curious, the workarounds are for the archive exceptions in portable_binary_archive, which should have been patched back in 1.40. These are actually in the examples folder, not fully supported by serialization at this time. Jeff

1 0

[GSoC] Boost.Process
by Moncef Mechri 29 Mar '10

29 Mar '10

Hi boosters, My name is Moncef Mechri (aka "fireboot" on IRC). I'm a 20 years old french student in my final undergraduate year at the Faculté des Sciences de Luminy, Marseille, France. I would like to apply as a student for the Boost.Process SoC idea. My main domains of interest include C and C++ programming languages, system programming (especially on POSIX systems), parallel computing, generic programming, object-oriented design, software optimizations, graph theory, and UI development (using Qt). So far I've used a couple of boost librairies : Boost.Thread, Boost.Random, some features from Boost.Interprocess (principally atomic operations), Boost.SmartPointers, Boost.Foreach and Boost.Bind. They were all a pleasure to use and it's why I've just written a (french) paper about one of them : Boost.thread [1]. I'll would be glad to help improving the set of high quality libraries that Boost is. I have some ideas to help finishing Boost.Process and I'd be happy to hear your opinions about them: 1) Abstract the string type used to name executables. This could be done for example using a traits class 2) Move find_executable_in_path() and executable_to_progname() to Boost.Filesystem. I think their job is filesystem-related so maybe it would be wise to move them accordingly. 3) On POSIX systems, provide raise(3) and kill(3) functions to respectively send a signal to the current process and send a signal to a child. Sending signals to unrelated process should probably not take place in Boost.Process but rather in Boost.Interprocess 4) On POSIX systems, when a process dies it becomes a zombie process until wait() is called. Since wait() blocks, things may become tricky if there are a lot of child process. When a process die, the SIGCHLD signal is sent to his creator. It might be nice to use that by setting up a SIGCHLD signal handler which calls wait() when this signal is received. Since a similar problem exists on Windows, Boost.Process should provide a similar solution on this platform, but I've not yet thought about a possible design for it. It might be also useful to provide a way to activate/deactivate this feature, for example with a macro BOOST_MANAGES_DEAD_PROCESS 5) Right now, boost::process::wait_children() returns the first exit code which is not equal to EXIT_SUCCESS, and if there are more than one process which finished abnormally, return values of those child processes are ignored. I think we could improve that by returning for example a vector<boost::process::status> instead of just one boost::process::status. Doing that, we can retrieve all the status codes. It might be useful to define a way to toggle on/off 6) Actually in Boost.Process, if the developer wants to be able to do asynchronous operations on Windows he has to define the BOOST_PROCESS_WINDOWS_USE_NAMED_PIPE macro. By doing so, it makes Boost.Process on Windows create named pipe for all streams even if asynchronous operations are not used in all of them. First of all I propose to add a boost::process::anonymous_pipe class to Boost.Process, and a boost::process::named_pipe class to Boost.Interprocess (because named pipe can be used between unrelated process). After that the developer should be able to choose between anonymous pipe or named pipe on a per-stream basis (but of course asynchronous operations will only work on streams using named pipes). Thanks for reading, it'd be nice if someone accept to comment my ideas Moncef Mechri. [1] http://fz-corp.net/?p=505

5 11

[Build] How to find a library (ICU)?
by Artyom 29 Mar '10

29 Mar '10

Hello, I'm trying to convert CMake build system for Boost.Locale to Boost.Build one. I have one obvious issue: how do find a library? How do I convert this CMake code to Boost.Build one: if(MSVC AND "${CMAKE_BUILD_TYPE}" STREQUAL "Debug") set(ICU_SUFFIX "d") endif() find_library(ICU_UC icuuc${ICU_SUFFIX}) find_library(ICU_DATA icudt NAMES icudata) find_library(ICU_I18N icuin${ICU_SUFFIX} NAMES icui18n${ICU_SUFFIX}) find_path(ICU_INCLUDE_DIR unicode/unistr.h) Note: I search for icuuc or icuucd under debug/msvc icuin or icui18n or icuind under debug/msvc icudata or icudt Also I need the build to fail or disable library if ICU not found. I've looked into the Jamfile of regex... but it does not look correctly for debug icu version when debug build is done! (And actually this is a bug). Also the code looks like a hack. Is there any specific way do to this? Thanks, Artyom

4 6

boost GSoC XML
by Qingli Ma 29 Mar '10

29 Mar '10

Hi ! I have studied some XML parses both in C++ and Java. After comparing with each other, I think that the API interface are more or less the same, however the performance and the complexity of programming is different. So I think mine is to improve the performance and make XML related programming easier. I decide that I am going to make a backend that supports the Reader and the dom interface. I've asked advice from my teachers and he think I am capable of such a job. Thank you!

2 2

New Boost.XInt Library, request preliminary review
by Chad Nelson 28 Mar '10

28 Mar '10

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi! I'm a long-time user (and admirer) of the Boost libraries, and I've just uploaded a new one to the Boost Vault for consideration: the Extended Integer (XInt) library, a unlimited-precision integer library that I've been working on for the last few months. I'd like to request a preliminary review of it, please. I know I was supposed to "determine interest" first, but I've seen posts going back at least five years, expressing a desire for such a library, so I didn't think that was really necessary in this case. :-) It's not perfect. The code is complete, as is the documentation text. But it doesn't yet support auto-linking or Windows DLLs, I'm not sure how the test suite would fit into the Boost test system, and I'm not sure I've got the Jamfile correct. But it should be sufficient for experimental use and review, and I'm eager to hear what you guys think of it. (I'm writing this in the wee hours of March 26th, I hope it isn't held in the moderation queue for too long.) - -- Chad Nelson Oak Circle Software, Inc. * * * -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkusSQoACgkQp9x9jeZ9/wSwrACfTvCVl6bEZbiTSzZ16WnB1E6B cusAoO8eBd2Ne3cYcpdVmjUoUwFmjlVU =5Ptl -----END PGP SIGNATURE-----

9 35

[GSoC] Boost.XML
by Ilie Halip 28 Mar '10

28 Mar '10

Hi! My name is Ilie Halip, and I'm a student at the Faculty of Computer Science in Iasi, Romania. I'm really interested in this year's Summer of Code, and stumbled upon your list of ideas yesterday. I have a few questions about the Boost.XML project. First, what actually needs to be done? The project proposal isn't clear about that. If it's about parsing using DOM/SAX, using XPath queries, then the project linked from the page already does that, right? So the project would involve working with the existing sources and adding validation, tests etc (as mentioned in the README)? How much working knowledge should a student have before trying to work on such a project? I must admit I haven't used Boost, nor libxml2 in the past, so I guess I should start reading documentation about both. I am good in C++, and I've been working with XML APIs for years, so that's not a problem. But the other two (Boost+libxml2) are? Is there a coding style I should follow if I were to work for this project to conform to Boost standards? Where can I find such info? Do you have any requirements from students working with GSoC? Something like: weekly reports, blogging about their experience, maintaining a wiki page about the status of the project? And last but not least... I'm actually employed right now, but my superiors are willing to give me more than 3 months of time off to be able to work for GSoC. Is that ok? Should I ask for more? I was looking over the timeline, and thought about getting a vacation between May 15th and August 30th. Would that be enough? Is it also alright if I stop working on the project for about a week in early June? Because I have a few exams then. Regards, Ilie. P.S. You can usually find me on IRC too (nickname: ihalip).

8 27

[bgl] Manual include necessary for is_in_subset predicate
by Matthias Walter 28 Mar '10

28 Mar '10

Hi! I'm using a filtered_graph for a project, which filters edges via the is_in_subset predicate. Is it intended that one must manually include boost/graph/detail/set_adaptor.hpp for this to work? If I only include boost/graph/filtered_graph.hpp and want to use the predicate, the compiler complains about missing set_contains function. I didn't find anything about manual includes in the docs, but maybe there are reasons for it. best regards Matthias Walter

2 1

[geometry] Inclusion in the next release?
by Romain CHANU 28 Mar '10

28 Mar '10

Hi boosters, Does anyone know if the Boost Geometry Library is going to be shipped in the next release of Boost? Cheers, Romain

4 12

GSoC 2010 : BigInt
by Mario Ynocente Castro 28 Mar '10

28 Mar '10

Hi, I'm a engineering student from Peru. I'm really interested in the BigInt project for GSoC 2010, but there's a part for which I would like a better explanation, the description says : "A successful proposal will include a discussion of licensing concerns". What does it mean? I must choose the license under which the code will be released and indicate it when I submit the aplication? -- Mario Ynocente Castro 20074016B FIIS - UNI

2 5

About Boost XML
by Qingli Ma 28 Mar '10

28 Mar '10

Hi! My idea about XML is listed below: 1.I have experience on processing larege scale xml files(database files).So I feel having boost proccess large xml files in SAX model will be useful and I've make that in Java before. 2.Reading spec about all kinds of XML APIs, and improve current Boost interfaces in Boost to support all kinds of processing without thinking about the backend implemention.By this, interfaces is independent from the backend, thus dynamic backend bindings is possible. 3.Maybe we need a new backend that serves for the API interface,like libxml2.It can parse,tranverse,writer and search(XPath) the document. 4.I am graduating this summer and I'll have enough time. Have you any sugguestions for me?

2 2

[GSoC 2010] Sweepline algorithm
by Marcin Fatyga 28 Mar '10

28 Mar '10

Hello, My name is Marcin Fatyga and I am doing double degree program in computer science and mathematics on Warsaw University. I would like to participate in GSoC 2010 - I would like to implement the sweepline algorithm and use it to solve the problems related to it. In my project I would like to implement the sweepline and then use Fortune's Algorithm to solve the Voronoi Diagram's problem. Then I would provide some modifications to solve the two remaining connected problems : Delanuay triangulation and medial axis. All of these problems have many applications in differnet fields of science and solving them could be useful to may users. Though I don't have quite much experience with the boost library itself, I am particularly interested in algorithms and have some experience with both C++ and generic programming. Though there is no geometry library in current release, I can see it is in development phase. Should the project be integrated with it/use it? Best wishes Marcin Fatyga

7 9

[preprocessor] Computational complexity analysis
by Lorenzo Caminiti 28 Mar '10

28 Mar '10

Hello all: Is there a computational complexity analysis of Boost.Preprocessor data structures? This would be in terms of preprocessing time. For example: Does BOOST_PP_SEQ_ELEM() run* in O(n)? Do BOOST_PP_TUPLE_ELEM() and BOOST_PP_ARRAY_ELEM() run* in O(1)? (*) "Run" within the preprocessor so maybe "expand" is a better term... Thank you. Lorenzo

2 3

[GSoC] Some Ideas about the Boost.Process
by Felipe Tanus 27 Mar '10

27 Mar '10

Hello, I have been studying the project idea about Boost.Process for a while. Some ideas/opinions poped up in my mind and I feel like to share. Please, comment. IMHO, the best design for the library is not to split the APIs from Windows and POSIX. I Believe that boost should provide a higher abstraction level, and get rid of the platform problems. 1.The current implementation of Boost.Process library has the class boost::process::child, and two classes that inherit it, win32_child and posix_child. I don't believe that this is the best solution. There is only one concept of child in both APIs; some resources are different, it is true, but the concept is only one. For example, the call "boost::process::win32_launch()" is defined to launch a process "the windows API way", with the Win32 context. I don't see why can't we create a process with this call in a POSIX system ignoring what don't apply to it (or find some similar concept and use it instead, as named pipes<->fifos). After all, if you are using a Win32 only class, there is no way to run in linux, so if the code works or don't, it does not matter. By doing this way, we could easy a possibly port to another system. This could be done with programming practices as suggested by Vicente Botet, in a previous topic [1] 2.The wait() method, to wait a process (child actually, but this is another problem) to die, is not asynchronous. Sometimes programmers want a synchronous wait() method, so there is no motive for we to remove this. We should implement a new asynchronous wait() method. This method should not be in the asio library, because it's process specific. It may require the asio library, or the asynchronous piece should be implemented in the boost.process. I'm not sure about this, both seems good for me, so please comment. 3.About the process creation, I think the following practice from the documentation should be avoided: “Another important requirement is to always pass at least one argument to the executable. This must be the name of the executable itself”. There is no motive to require a parameter that you can deduce by yourself. The first parameter, in this case, should be implicit. 4.Would really be nice boost::process::launch() be able to receive any kind of string? This tend to let the programmer go for a single platform solution. As a multiplatform library, this may be avoided. I'm not sure about this matter as well, but if the library is here to provide a higher abstraction level, should it also accept API related types? I believe it should not. There is also another points that I would like to discuss in my GSoC proposal; They are well known problems so I'll just cite they: List and access other processes functionality Named pipes and FIFO (following the item #1, would be the same thing? Something would change? Something to be researched yet) move wait from child to process (as well as future asynchronous wait) Deal with process killing bugs (as well as any other known issue) Test platform issues. Should this be enough for a GSoC proposal? Do you have any other suggestion about what could I discuss in it? Thank you for your time, []'s [1] http://thread.gmane.org/gmane.comp.lib.boost.devel/188736 -- Felipe de Oliveira Tanus E-mail: fotanus(a)gmail.com Blog: http://www.itlife.com.br Site: http://www.inf.ufrgs.br/~fotanus/ ----- "All we have to decide is what to do with the time that is given us." - Gandalf

7 18

GSOC query for Heaps and Que
by Chirag 27 Mar '10

27 Mar '10

Hello Sir The Boost C++ library has mutable_heap and mutable_que and the current container works perfectly for basic datatypes like double , int etc but for datatypes like pointers it requires that user should have knowledge of property_map types. Sir for making mutable heaps , can we ask user for a hash function from the user for the data type he want to make the heap. This way we can hash each newly added value to heap and store pointer for that which will point to its location in the original heap. Here two problem i am facing 1) Can user provide a hash function for all data types 2) Worst case of hashing search would be O(n) though it chances are very low . I know O(n) case is not wat we are aiming to achieve but for users who dont want to get into understanding of property map they can use this heap instead , and I am thinking of giving it as a option to the already available mutable que in boost. This is just a idea I am proposing and its definately not final , I am thinking on other ways to improve it . I just want to know if it is a good option to give or not. Thanks Chirag IIT guwahati -- Life is short live it happily

1 0

Stability: More on 3 level Boost libraries
by vicente.botet 27 Mar '10

27 Mar '10

Hi, I would like to come back to the 3 level proposition but from a different point of view (stability and quality) 1st level: stable Libraries belonging to this level must be very stable, any modification on the public interface must be reviewed. The goal been that changes in these libraries don't break user code, even if they will need to recompile. Libraries can pretent to be in this level if the library use only libraries at this level, has not introduced breaking changes for a given amount of time and of course if the author wants to be constrained to have a review for changes on the public interface and to correct quicky the possible tickets. 2nd level: quite stable Libraries at this level, even if stable, introduce breaking changes from time to time. Libraries can go to this level if the library use only libraries at this level or the 1st level, after a deep review of the of the interfaces, the documentation, the implementation and the test coverage and have a reduced number of tickets since a to be defined period. 3rd level: unstable It is assumed that young libraries will have a lot of breaking changes at the public interface level. Libraries can go to this level after a review of the interfaces and the documentation. Comments are welcome, _____________________ Vicente Juan Botet Escribá

10 22

Help with GSoC; BigInt and Heaps & Queue
by Lucas Gambarra 27 Mar '10

27 Mar '10

Hi, I'm very interested in participating in GSoC. While watching the list of ideas proposed by the boost C++ Libraries, I was really interested in two of them: 'Heaps & Queues' and 'BigInt'. I am a student of Computing Sciences of the Federal University of Paraíba - Brazil. I wanted information on how to contact the mentortes of such projects. Could someone help me? Forgive me for my English. ------------ --------- --------- --------- --------- --------- --------- --------- -------- Lucas Lucena Gambarra Estagiário no Laboratório de Sistemas Digitais (LASID - UFPB) Projeto Brazil-IP 2010 email: lucas.ufpb(a)gmail.com.br MSN: lucas_gambarra@hotmail. com

2 1

The problems with Boost development
by Vladimir Prus 27 Mar '10

27 Mar '10

Hello, in a recent post, Dave listed a few things that he thinks are wrong with Boost development, at present, quoting: I know I'm not the first person to notice that, as Boost has grown, it has become harder and harder to manage, Subversion is getting slow, our issue tracker is full to overflowing, and the release process is a full-time job. It seems to be important, right now, to discuss whether this problems are real, and what problems are most important. So, I would like to ask that everybody who is somehow involved in *development* -- whether in writing code, triaging bugs, sending patches, or managing thing, list three most important problems with Boost now. Please keep the items to a sentence or two, so that we can easily collect the problems. Here's my take: - Unmaintained components. Many authors are no longer active, and we have no procedures for taking over. - Reviews that are getting rare and, IMO, less interesting then before. - Turnaround time of test results Thanks, Volodya

29 67

[variant] compatibility with move-constructible objects
by Zachary Turner 26 Mar '10

26 Mar '10

I have the following rough sequence of typedefs: struct empty {}; typedef std::unique_ptr<foo> foo_ptr; typedef std::unique_ptr<bar> bar_ptr; typedef std::vector<foo_ptr> foo_ptr_vec; typedef std::vector<bar_ptr> bar_ptr_vec; typedef std::variant<empty, foo_ptr_vec, bar_ptr_vec> my_variant; I then declare an instance of my_variant in a class, and make the class moveable and noncopyable. class my_class { my_class(const my_class&); my_class& my_class(const my_class&); my_variant v_; public: my_class(my_class&& other) : v_(std::move(other.v_)) { } }; I cannot get this to compile under MSVC 10 and boost 1.42. In theory I don't see why this shouldn't be ok. Even though the objects are not copy-constructible due to unique_ptr, they are move constructible. The errors are quite long, but you can see it's trying to invoke vector::operator= from within the variant code. Is this just a technical limitation of variant, or a bug? 1> behavior_collection.cpp 1>C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(2144): error C2248: 'behavior_collection::behavior_impl<Output>::operator =' : cannot access private member declared in class 'behavior_collection::behavior_impl<Output>' 1> with 1> [ 1> Output=kinematic_output 1> ] 1> c:\users\zach\documents\visual studio 2010\projects\dxdemo\dxdemo\behavior_collection.h(15) : see declaration of 'behavior_collection::behavior_impl<Output>::operator =' 1> with 1> [ 1> Output=kinematic_output 1> ] 1> C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\xutility(2165) : see reference to function template instantiation '_OutIt std::_Copy_impl<_InIt,_OutIt>(_InIt,_InIt,_OutIt,std::_Nonscalar_ptr_iterator_tag)' being compiled 1> with 1> [ 1> _OutIt=behavior_collection::behavior_impl<kinematic_output> *, 1> _InIt=behavior_collection::behavior_impl<kinematic_output> * 1> ] 1> C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\vector(719) : see reference to function template instantiation '_OutIt std::_Copy_impl<behavior_collection::behavior_impl<Output>*,behavior_collection::behavior_impl<Output>*>(_InIt,_InIt,_OutIt)' being compiled 1> with 1> [ 1> _OutIt=behavior_collection::behavior_impl<kinematic_output> *, 1> Output=kinematic_output, 1> _InIt=behavior_collection::behavior_impl<kinematic_output> * 1> ] 1> C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include\vector(709) : while compiling class template member function 'std::vector<_Ty> &std::vector<_Ty>::operator =(const std::vector<_Ty> &)' 1> with 1> [ 1> _Ty=behavior_collection::behavior_impl<kinematic_output> 1> ] 1> C:\dev\boost\1.42.0\boost/type_traits/is_pod.hpp(34) : see reference to class template instantiation 'std::vector<_Ty>' being compiled 1> with 1> [ 1> _Ty=behavior_collection::behavior_impl<kinematic_output> 1> ] 1> C:\dev\boost\1.42.0\boost/type_traits/is_pod.hpp(129) : see reference to class template instantiation 'boost::detail::is_pod_impl<T>' being compiled 1> with 1> [ 1> T=std::vector<behavior_collection::behavior_impl<kinematic_output>> 1> ] 1> C:\dev\boost\1.42.0\boost/type_traits/has_trivial_constructor.hpp(27) : see reference to class template instantiation 'boost::is_pod<T>' being compiled 1> with 1> [ 1> T=std::vector<behavior_collection::behavior_impl<kinematic_output>> 1> ] 1> C:\dev\boost\1.42.0\boost/type_traits/has_trivial_constructor.hpp(36) : see reference to class template instantiation 'boost::detail::has_trivial_ctor_impl<T>' being compiled 1> with 1> [ 1> T=std::vector<behavior_collection::behavior_impl<kinematic_output>> 1> ] 1> C:\dev\boost\1.42.0\boost/type_traits/has_nothrow_constructor.hpp(23) : see reference to class template instantiation 'boost::has_trivial_constructor<T>' being compiled 1> with 1> [ 1> T=std::vector<behavior_collection::behavior_impl<kinematic_output>> 1> ] 1> C:\dev\boost\1.42.0\boost/type_traits/has_nothrow_constructor.hpp(32) : see reference to class template instantiation 'boost::detail::has_nothrow_constructor_imp<T>' being compiled 1> with 1> [ 1> T=std::vector<behavior_collection::behavior_impl<kinematic_output>> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/not.hpp(41) : see reference to class template instantiation 'boost::has_nothrow_constructor<T>' being compiled 1> with 1> [ 1> T=std::vector<behavior_collection::behavior_impl<kinematic_output>> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/aux_/preprocessed/plain/and.hpp(25) : see reference to class template instantiation 'boost::mpl::not_<T>' being compiled 1> with 1> [ 1> T=boost::has_nothrow_constructor<std::vector<behavior_collection::behavior_impl<kinematic_output>>> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/aux_/preprocessed/plain/and.hpp(55) : see reference to class template instantiation 'boost::mpl::aux::and_impl<C_,T1,T2,T3,T4>' being compiled 1> with 1> [ 1> C_=true, 1> T1=boost::mpl::apply1<boost::mpl::protect<boost::detail::variant::find_fallback_type_pred>,boost::mpl::l_iter<boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>>>, 1> T2=boost::mpl::true_, 1> T3=boost::mpl::true_, 1> T4=boost::mpl::true_ 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/iter_fold_if.hpp(46) : see reference to class template instantiation 'boost::mpl::and_<T1,T2>' being compiled 1> with 1> [ 1> T1=boost::mpl::not_<boost::is_same<boost::mpl::l_iter<boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>>,boost::mpl::l_iter<boost::mpl::l_end>>>, 1> T2=boost::mpl::apply1<boost::mpl::protect<boost::detail::variant::find_fallback_type_pred>,boost::mpl::l_iter<boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>>> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/aux_/preprocessed/plain/apply_wrap.hpp(49) : see reference to class template instantiation 'boost::mpl::aux::iter_fold_if_pred<Predicate,LastIterator>::apply<State,Iterator>' being compiled 1> with 1> [ 1> Predicate=boost::mpl::protect<boost::detail::variant::find_fallback_type_pred>, 1> LastIterator=boost::mpl::l_iter<boost::mpl::l_end>, 1> State=boost::mpl::int_<1>, 1> Iterator=boost::mpl::l_iter<boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/aux_/preprocessed/plain/apply.hpp(63) : see reference to class template instantiation 'boost::mpl::apply_wrap2<F,T1,T2>' being compiled 1> with 1> [ 1> F=boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::detail::variant::find_fallback_type_pred>,boost::mpl::l_iter<boost::mpl::l_end>>>, 1> T1=boost::mpl::int_<1>, 1> T2=boost::mpl::l_iter<boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/aux_/preprocessed/plain/iter_fold_if_impl.hpp(62) : see reference to class template instantiation 'boost::mpl::apply2<F,T1,T2>' being compiled 1> with 1> [ 1> F=boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::detail::variant::find_fallback_type_pred>,boost::mpl::l_iter<boost::mpl::l_end>>>, 1> T1=boost::mpl::int_<1>, 1> T2=boost::mpl::l_iter<boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/aux_/preprocessed/plain/iter_fold_if_impl.hpp(102) : see reference to class template instantiation 'boost::mpl::aux::iter_fold_if_forward_step<Iterator,State,ForwardOp,Predicate>' being compiled 1> with 1> [ 1> Iterator=boost::mpl::l_iter<boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>>, 1> State=boost::mpl::int_<1>, 1> ForwardOp=boost::mpl::protect<boost::mpl::next<boost::mpl::na>>, 1> Predicate=boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::detail::variant::find_fallback_type_pred>,boost::mpl::l_iter<boost::mpl::l_end>>> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/iter_fold_if.hpp(94) : see reference to class template instantiation 'boost::mpl::aux::iter_fold_if_impl<Iterator,State,ForwardOp,ForwardPredicate,BackwardOp,BackwardPredicate>' being compiled 1> with 1> [ 1> Iterator=boost::mpl::l_iter<boost::mpl::l_item<boost::mpl::long_<3>,behavior_collection::null_behavior,boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>>>, 1> State=boost::mpl::int_<0>, 1> ForwardOp=boost::mpl::protect<boost::mpl::next<boost::mpl::na>>, 1> ForwardPredicate=boost::mpl::protect<boost::mpl::aux::iter_fold_if_pred<boost::mpl::protect<boost::detail::variant::find_fallback_type_pred>,boost::mpl::l_iter<boost::mpl::l_end>>>, 1> BackwardOp=boost::mpl::na, 1> BackwardPredicate=boost::mpl::always<boost::mpl::false_> 1> ] 1> C:\dev\boost\1.42.0\boost/mpl/iter_fold_if.hpp(102) : see reference to class template instantiation 'boost::mpl::iter_fold_if<Sequence,State,ForwardOp,ForwardPredicate>::result_' being compiled 1> with 1> [ 1> Sequence=boost::mpl::l_item<boost::mpl::long_<3>,behavior_collection::null_behavior,boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>>, 1> State=boost::mpl::int_<0>, 1> ForwardOp=boost::mpl::protect<boost::mpl::next<boost::mpl::na>>, 1> ForwardPredicate=boost::mpl::protect<boost::detail::variant::find_fallback_type_pred> 1> ] 1> C:\dev\boost\1.42.0\boost/variant/variant.hpp(170) : see reference to class template instantiation 'boost::mpl::iter_fold_if<Sequence,State,ForwardOp,ForwardPredicate>' being compiled 1> with 1> [ 1> Sequence=boost::mpl::l_item<boost::mpl::long_<3>,behavior_collection::null_behavior,boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>>, 1> State=boost::mpl::int_<0>, 1> ForwardOp=boost::mpl::protect<boost::mpl::next<boost::mpl::na>>, 1> ForwardPredicate=boost::mpl::protect<boost::detail::variant::find_fallback_type_pred> 1> ] 1> C:\dev\boost\1.42.0\boost/variant/variant.hpp(1079) : see reference to class template instantiation 'boost::detail::variant::find_fallback_type<Types>' being compiled 1> with 1> [ 1> Types=boost::mpl::l_item<boost::mpl::long_<3>,behavior_collection::null_behavior,boost::mpl::l_item<boost::mpl::long_<2>,std::vector<behavior_collection::behavior_impl<kinematic_output>>,boost::mpl::l_item<boost::mpl::long_<1>,std::vector<behavior_collection::behavior_impl<dynamic_output>>,boost::mpl::l_end>>> 1> ] 1> c:\users\zach\documents\visual studio 2010\projects\dxdemo\dxdemo\behavior_collection.h(39) : see reference to class template instantiation 'boost::variant<T0_,T1,T2>' being compiled 1> with 1> [ 1> T0_=behavior_collection::null_behavior, 1> T1=behavior_collection::kinematic_behaviors, 1> T2=behavior_collection::dynamic_behaviors 1> ]

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Re: [boost] Library dependencies and intrer-library code reuse
by Brian Wood 26 Mar '10

26 Mar '10

Dave Abrahams writes: At Fri, 26 Mar 2010 03:45:51 -0700 (PDT), Vicente Botet Escriba wrote: <snip whole thread> > > > > > > > Please don't top post. > > Vicente Please don't overquote. just-for-symmetry-ly y'rs, Dave, are you aware your messages are being duplicated on the list? I've seen that a few times with others, but often it is the case with your messages. I would also appreciate it if people would stop with the top posting and excessive quoting. -- Brian Wood Ebenezer Enterprises http://webEbenezer.net (651) 251-9384

2 1

GSoC Parallel BGP implementation
by Naresh Reddy Sankapelly 26 Mar '10

26 Mar '10

hi, I am naresh, a student pursuing B.Tech 4th year from Indian Institute of Information Technology- Allahabad, India. I am keen to get involved in open source project development as part of GSoC 2010 with Boost. I went though the ideas list provided in the site. I'm interested to work on parallel graph algorithms for BGL in particular with graph connectives project. I took this because I have worked on parallelizing graph algorithms as a part of my Parallel Computing course. I would be happy to know few things. 1. Can I work on library of my own for parallel computing like Intel's TBB ?or should I use MPI only? 2. It would be helpful for me if I can have one more student working on sequential part of graph algorithms. Is it allowed? If it is, and any one interested please reply me back. 3. Can I get few more details of Computer Vision algorithms? I look forward to your replies soon. Thanks

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Is there anyone can tell me who is in charge of the Google Summer of Code in boost community for this year
by Qingli Ma 26 Mar '10

26 Mar '10

Hello , I want to take part in the Google Summer of Code( http://socghop.appspot.com/site/home/site) but can not find who I should contact. XML is very useful.I have used Jdom,dom and SAX for XML.Therefor,I want get the boost library support XML operations better. So ,is there anyone can tell me who should I contact with to tell my ideas and ask for suggestions.

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Should Boost adopt pimpl/d-pointer as much as it can?
by Artyom 26 Mar '10

26 Mar '10

Hello, There are recently lots of discussions about current development issues. I would like to point to one small but extremely important issue (from user point of view). Boost has too many logic in header part of library, by meaning too much I mean painfully too much. I think that Boost should adopt as policy: 1) All implementation related code **should** be put in sources. 2) Any non-template based class should have opaque/d/pimpl pointer in its body. Why? I give you a simple example: one of the pearls of Boost: Boost.Asio is one of most painful libraries to use. I created a simple example of echo server written with Boost.Asio and written with a small pimpl-wrapped Boost.Asio (I had written myself as proof of concept - that uses boost.asio in implementation): http://art-blog.no-ip.info/files/asio_pimpl.tar.gz These are results of compilation times with gcc-4.3 (seconds): -O0 -O2 -O3 -O2+link asio 2.56 4.65 4.96 4.75 pimpl 0.59 0.85 0.89 0.94 diff *4.3 *5.5 *5.6 *5.05 And this is trivial echo server. When the code gets larger and bigger it becomes even more painful. For me, compilation of components based on Asio is total nightmare because of unacceptable compilation times. Another issue is executable size. I had took same echo sever placed in 10 object compiled under different namespaces once I did it with Boost.Asio and then I did it with pimpl-ed Asio. Result (liked executable size with gcc-4.3): Build Size (-Os stripped) Asio: 245K Pimpl: 190K ---------------------------- Conclusions: ============ There are too many good libraries (Asio as good example) that use headers too much or headers only, this terribly increases compilation times and makes executable sizes much bigger (this is especially relevant for embedded systems). Should Boost wellcome pimpled libraries more? I think yes. It would solve two problems: 1. It would give faster compilation times. 2. It would allow to provide changes easily without breaking compatibility (even would allow to provide backward ABI compatibility) Dear Boosters. What do you think about? Artyom

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Re: [boost] GSOC query for Heaps and Que
by Andrew Sutton 26 Mar '10

26 Mar '10

Hi Chirag, 1) Relaxed Fibbonacci Heaps by Chandrasekhar Boyapati C. Pandu Rangan > 2) Relaxed Weak Que by Amr Elmasry Claus Jensen Jyrki Katajainen > 3) Soft Heap by Bernand Chazelle > > Please tell can I add these datastuctures to my proposal for GSOC . > I think those data structures are in the spirit of the proposal. It would not be a bad idea. > I also want to add radix tree and generalized version of union find > datastructure into my proposal. > Will it be a good proposal ? > That might be a little ambitious for a 3 month project. I would try to keep your proposal a little more focused. Andrew Sutton andrew.n.sutton(a)gmail.com

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Re: [boost] [gil] Can not open test.jpg
by Mariusz Kwiczala 26 Mar '10

26 Mar '10

Christian, >>This file needs to be swapped out. Will do that next week. >Done. Thank you. >Marius, do you wanna try out it the new gil::io? It's located here: >http://gil-contributions.googlecode.com/svn/trunk/gil_2/boost/gil/extension / Will it be available in 1.43? >Let me know if you have questions, problems, etc. I have one suggestion: Gil::Io extensions do not work without required libjpeg libpng, libtiff ... There is no way to run examples from "boost_1_42_0\libs\gil\example" without required libs. There are problems to match boost::gil and "external graphlibs" i.e. http://stackoverflow.com/questions/2442335/libpng-boostgil-png-infopp-null-n ot-found I think that libjpeg libpng, libtiff libs should be included into boost and compiled with use bjam. Regards, Mariusz

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Re: [boost] [transact] code in sandbox
by vicente.botet 26 Mar '10

26 Mar '10

----- Original Message ----- From: <strasser(a)uni-bremen.de> To: "vicente.botet" <vicente.botet(a)wanadoo.fr> Sent: Friday, February 12, 2010 2:00 AM Subject: Re: Re:[boost] [transact] code in sandbox > Zitat von "vicente.botet" <vicente.botet(a)wanadoo.fr>: >> IMO the transaction must be accesible during the handling of the exceptions. > > why? I see one reason in your examples (although I don't understand > force_to_abort, maybe that's another one, see below), and that is > committing on exception: > >>>> #define BOOST_TRANSACT_BASIC_RETHROW(TXMGR, TX, E) \\ >>>> catch (E&) {(TX).commit(); throw;} > > why can't the user create his own try/catch block for that?: > (using your syntax) > BOOST_TRANSACT_ATOMIC(_) { > try{ > ... > }catch(my_exc &){ > _.commit(); > } > }BOOST_TRANSACT_COMMIT(); Yes this is always possible. However, transactions and exception handling are used for the same goal, recover from errors. Thus it is interesting to handle them in the same way and in a single try-cactch block. >> _.force_to_abort(); > > what does this do? retry the transaction but make sure it fails? why? > why don't you just go ahead and throw an exception that is not caught > inside the transaction scope? When the user wants to undo whatever the transacton block did, the simple way is to abort the transaction. Don't forget that transactions can be used in a single-threaded application to make exception-safe code. >>> at some point I think the macros loose their benefit and you might >>> just as well write the loop yourself. e.g. if you need to execute >>> custom code on retry. >> >> You are right. The specific macros are not important. What is >> important is that the provided macros can be extended naturaly. > > that's what I'm not so sure of. if you need to control the number of > retries or execute custom code on retry, why don't you just write this > instead of using macros: > > for(int c=0;c<10;++c){ > try{ > transaction tx; > ... > tx.commit(); > break; > }catch(isolation_exceotion &e){ > e.unwind(); > std::cerr << "my custom retry code\n"; > } > } > > doesn't seem a whole lot more verbose to me. > but I'm not against adding more macros for convenience. the one thing > I would like is not complicating the simplest use case. the user > shouldn't have to to add something like "(_)" if he doesn't need it > and has no idea what it is there for. the default use case should be > as simple as possible. I would like also to don't need to add a transaction variable name. I need the name of the transaction variables to implement break and continue in a language-like. From my side, the inclusion of the macros is to be close to what the user will write if the language provided some specific transaction constructs. The user is always free to use directly the class interface. The question is what is the simple case. for an INNER transaction Boost.STM provides a macro #define BOOST_STM_USE_ATOMIC(TX) \ for (boost::stm::transaction TX; \ ! TX.committed() \ && TX.restart(); \ TX.commit()) that the user ca use like BOOST_STM_USE_ATOMIC(_) { // transaction statement } In this case every exception scape the transaction block, and will be managed by the outer transaction block. This is simple, recall a possible language statement transaction { // transaction statements } The parameter is needed only if we want to return from the transaction block. If needed we can add a simple #define BOOST_STM_INNER_TRANSACTION \ for (boost::stm::transaction __TX; \ ! __TX.committed() \ && __TX.restart(); \ __TX.commit()) use as follows BOOST_STM_INNER_TRANSACTION { // transaction statement } As I said in a preceding post, we can provide initialy both sets of macros and see which set the users use more often. Best, Vicente

7 48

About adding XML API in the boost.
by Qingli Ma 26 Mar '10

26 Mar '10

Hello,everyone! I am from china and want to take part in the boost commnnity. Support for XML is limited in boost, so I want to do something about this. Also I see some information at https://svn.boost.org/trac/boost/wiki/SoC2010. I wish to take part in the Google Summer of Code(http://socghop.appspot.com/). Can you give me some ideas about that?Who should I contact with? Thank you for your sugguestion!

2 1

GSOC - Boost.XML
by Shrinidhi Hudli 26 Mar '10

26 Mar '10

Hello, I am interested to send a proposal to work on Boost.XML for GSOC 2010. I have a couple of questions: 1. Would it make sense to provide C++ binding for XML using XSD? This would make it much more convenient that using parsers explicitly. 2. Is the project mostly to develop an abstraction for the backend parsers so that different parsers can be "plugged-in"? Thanks for the clarification. -- Shrinidhi Hudli

2 1

Re: [boost] [lexical_cast] A non-throwing lexical cast? [Was: 5Observations - My experience with the boost libraries]
by pete＠pcbartlett.com 26 Mar '10

26 Mar '10

On Fri 26/03/10 01:25 , Gennadiy Rozental <rogeeff(a)gmail.com> wrote: > Rene Rivera writes: > > > > Tom Brinkman wrote: > > > boost::lexical_cast_no_throw() > > > > Or.. > > > > template > > T lexical_cast(const S & arg, const T & error_default_value); > > > I've implemented later in my own version of lexical cast. In 99% of > the time > this is exactly what I need: either convert string to number or take > this > default value. Another good consequence is that I do not need > template parameter > anymore. > Gennadiy Looking at the various threads it seems like three different behaviours in the event of conversion failure have been requested. - Default Value - boost::system::error_code - throw custom exception. So this would suggest an interface like template< typename T , typename S, typename FailureHandler > lexical_cast(S const& arg , FailureHandler fh) with specializations if FailureHandler = T or FailureHandler = boost::system::error_code&. You do lose your "good consequence" with this formulation though. As I said in another message, the original author of lexical_cast has said several times over the years that doing something like this is too far from the spirit of a *_cast, though, so if it gets into Boost I think it will have to be in the StringConvert library.

1 0

[lexical_cast] A non-throwing lexical cast? [Was: 5 Observations - My experience with the boost libraries]
by pete＠pcbartlett.com 26 Mar '10

26 Mar '10

On Wed 24/03/10 03:40 , Jonathan Franklin <franklin.jonathan(a)gmail.com> wrote: > On Tue, Mar 23, 2010 at 9:31 PM, Tom Brinkman wrote: > > ... All I'm saying is that in the real world, most > > projects are mixed C/C++ and that the needs of both communities > need > > to be addressed if boost is going to remain relevent. > For the sake of not arguing, let's assume that your assertion is > true. > Let's hear your *actionable* proposal for improving boost. E.g. > show > us the better interface for <insert Boost library here> Taking an example from way back at the start othis thread, in my personal experience a non-throwing version of lexical_cast<> would be very nice. If I look at the cases where I pass user data through my libraries into boost libraries without some pre-validation, there are very few, and naturally these are the cases where the validation would as difficult as the "parse": - boost::spirit::phrase_parse - Just returns a true/false, and I build a nice context-driven error message myself if necessary. - boost::lexical_cast - throws. Almost always needs to be caught and re-thrown.

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Re: [boost] [lexical_cast] A non-throwing lexical cast? [Was: 5 Observations - My experience with the boost libraries]
by Pete Bartlett 25 Mar '10

25 Mar '10

Kim Barrett wrote: > On Mar 24, 2010, at 5:20 PM, Bruno Santos wrote: >>boost::bad_lexical_cast is not derived from >>my_project::invalid_user_input o or whatever. This happens a lot with >>boost::lexical_cast. >> >If the user data is data that comes from a file or user interface, I >agree in your assertion. > >However, if it's from someone using your library, it's an obvious >programming error, doing exception translation in this case is >pointless. Agreed, but the source of data in a text format that should be a numeric format is much more likely to be end-user systems and inputs rather than that created within a client application, IME. >Anyway, in my opinion, passing a boost::system::error_code as the second >parameter for a non throwing version would be the best solution. As Jeff points out, others have been here before us, and it looks like the proposed Boost.StringConvert is the result of prior discussions. Perhaps our energies would be best spent making sure that library meets our needs by being reviewers or even the review manager [one is still needed, according to the schedule]. Pete

1 0

GSOC 2010 Boost-Graph
by Chinmaya Poswalia 25 Mar '10

25 Mar '10

Hi Myself Chinmaya Poswalia Computer Science an Engineering B.Tech, Indian Institute of Technology, Guwahati I am finding all the graph topic(my favorite topic to work on) very interesting that's why i asked a lot of questions regarding all in one mail. - i want to work on semantic graph - how about maintaining an adjacency list, denote V as nodes and E as edges, so the space complexity will be O(V+E). - Also we can employ pointers of type void* to point to edges/vertices of different types so as to maintain the graph of different edge and vertex types. - rather than employing a vector in each node and edge either we should allocate space during insertion or we maintain the size of vector array by ourself. - Through generic programming, all the operations being implemented on graph up till now will be made applicable on these new members of the library. - various functions that can be induced on these graphs are 1. Distribution of node degree 2. finding clustering co-efficient of semantic graph 3. relevance of a link and node 4. scale on semantic graph 5. disparity of connected types/dispersion co-efficient. - Semantic graph are generating huge level of importance in networking (network semantics on web), video screening, statistical analysis of data,etc so it will be a great thing to work on it. Can you suggest some more links to read on for these I am working on my proposal about the graph and your help is crucial for me. With regards Chinmaya

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[log] Boost.Log formal review result
by Vladimir Prus 25 Mar '10

25 Mar '10

First of all, I would like to thank Andrey for this submission and the active discussion during the review. I also would like to thank everybody who participated in the review. The comments on the library were generally positive. Several reviewers have tried it in practical projects already, and found it superior to other libraries. It clearly will benefit the users of Boost right away. Therefore, the library is accepted. Congratulations, Andrey! On the other hand, some concerns about the ease of use and performance and implementation details were raised. Of those, some can be easily addressed as part of normal maintenance, while some seem to require significant rework and may change the library quite consirably. Therefore, the library is accepted subject to several conditions -- listed below under "Critical issues". Because the changes can be large, I think a mini-require is required when those issues are addressed. To avoid delays, it's probably not necessary to formally schedule and conduct a mini-review -- just posting a email asking for discussion will be sufficient. Statistics ========== There were roughly 300 emails during formal review (I have a mbox archive if anybody needs it). The following persons submitted a review with a vote. Some of votes are "provisional", this is not reflected below, but affects the list of critical issues below. - Boris Schaeling (yes) - Roland Bock (yes) - Ralf Globisch (yes) - Sean Chittenden (yes) - Darryl Green (no) - Tom Brinkman (no) - Barend (yes) - Sam Gundry (yes) - Vicente Botet (yes) - Robert Stewart (yes) - Alexander Arhipenko (yes) - "M-Square" (yes) Critical issues =============== These issues must be addressed, and be passed through informal mini-review, before the library can be added to SVN. - It appears that the 'trivial' logging is not sufficiently good to just take and use. The library should provide an out-of-the-box mechanism that: - supports channel/severity attributes, without creating new logger for each severity. It also should be possible to filter out specific channel by essentially poking at some "map", and without manually composing a new filter that checks for a set of allowed channels sequentally. I believe that at least Christian, Roland, Robert and myself requested this. - has no observable effect on compile time. One second (or more) that trivial.hpp imposes is not acceptable. - outputs to console by default, but permits changing that - outputs only component/severity/message by default, but probably permits changing that. - By default, the library should try hard to continue working no matter what errors happen during processign a log record -- including things like invalid attribute names or types, or other exceptions. - The library should not reinvent wheels. In particular, custom implementations of TSS and RW mutex seems like a very bad idea. Use of a custom lambda implementation was pointed by many as not great -- we already have a couple, so let's not add more to the mix. - Library interface is too geared towards lambda. In particular, implementing formatters/filters as free-standing functions appears to require considerably more code. In particular, it should be possible to access an attribute using a single function call. Also, logging::extract taking a lambda for callback complicates matters, it's desirable to have a more direct variant. Important issues ================ These issues are important enough to be mentioned here, but can be addressed as convenient. - The reported run-time performance can be improved. In particular the performance with date attributes seems scary and 2x slowdown relative to some other library in the 'most records are filtered out' case is also concerning. - I don't think it was satisfactory explained why 'attr' exists in two namespaces, as opposed to being a single type that is used for both formatting and filtering. Other notes =========== These issues seem important and should be considered, but might not even be fixable within the current design. - Several reviewers said the library is "too flexible" and this makes it harder to understand. Probably nothing can be done about that at this point, but interesting data point notwithstanding. - It was suggested that the library include an API that another Boost log may use in a way that permits plugging another logging library should end user of a Boost so desire. This seems a good idea, but I think it's up to Andrey to implement such API or not. - Alternative design approaches were proposed, in particular (i) permitting user log records and templating/basing other components on a user-defined record type and (ii) using compile-time indexing to access attributes. Also, it was proposed that named parameters not be necessary to use the library, and a more conventional interface be available. It does not seem that implementing those suggestions is fully possible without writing a different library from scratch, so it's up to Andrey to consider those proposals. - It was suggested to use newer Spirit to address poor compile times for the library itself. Thanks, Volodya

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[log] How to derive from a logger
by Andreas Huber 25 Mar '10

25 Mar '10

Hi Andrey As discussed earlier, we're kind of desperate to add functionality to a logger class provided by Boost.Log. Instead of duplicating severity_channel_logger_mt, I'm wondering whether it's a good idea to derive from it, as follows: class Logger : public ::boost::log::sources::severity_channel_logger_mt< Severity > { public: typedef ::boost::log::sources::severity_channel_logger_mt< Severity > logger_base; BOOST_LOG_FORWARD_LOGGER_CONSTRUCTORS(Tracer) void SetMinimumSeverity(Severity severity); Severity GetMinimumSeverity(); private: Severity minimumSeverity; }; Elsewhere we'd use this class as follows: BOOST_LOG_DECLARE_GLOBAL_LOGGER_INIT(Whatever, Logger) { // ... } It seems to work, but is this a good idea? Thanks & Regards, -- Andreas Huber When replying by private email, please remove the words spam and trap from the address shown in the header.

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Re: [boost] GSOC 2010 Boost-Graph
by Chinmaya Poswalia 25 Mar '10

25 Mar '10

On Thu, Mar 25, 2010 at 3:21 AM, Chinmaya Poswalia < chinmaya.poswalia(a)gmail.com> wrote: > Hi Andrew, > I am finding all the graph topic(my favorite topic to work on) very > interesting that's why i asked a lot of questions regarding all in one mail. > > > - i want to work on semantic graph > > > - how about maintaining an adjacency list, denote V as nodes and E as > edges, so the space complexity will be O(V+E). > > > - Also we can employ pointers of type void* to point to edges/vertices > of different types so as to maintain the graph of different edge and vertex > types. > > > - rather than employing a vector in each node and edge either we should > allocate space during insertion or we maintain the size of vector array by > ourself. > > > - Through generic programming, all the operations being implemented on > graph up till now will be made applicable on these new members of the > library. > - various functions that can be induced on these graphs are > > > 1. Distribution of node degree > 2. finding clustering co-efficient of semantic graph > 3. relevance of a link and node > 4. scale on semantic graph > 5. disparity of connected types/dispersion co-efficient. > > > - Semantic graph are generating huge level of importance in networking > (network semantics on web), video screening, statistical analysis of > data,etc so it will be a great thing to work on it. > > Can you suggest some more links to read on for these > > > > I am working on my proposal about the graph and your help is crucial for > me. > With regards > Chinmaya >

1 0

GSOC Proposal for BIGINT - Long Mail
by swagat konchada 25 Mar '10

25 Mar '10

I had a look around in the Boost Sandbox and I found a BigInt implementation done by zeux during GSoC 07. I had a look at the code and I wanted to know its deficiencies. I'm interested in proposing some improvements in bigint and new bigdecimal implementation that is building on this code. There are 2 questions that I wanted to ask the list before moving further on this track: 1. Is there sufficient interest for a BigDecimal proposal on the lines of the Java implementation of BigDecimal (or has there been some prior work that can be used as a foundation?) 2. What are the deficiencies of bigint that have prevented its inclusion into the Boost distribution so as to address the same as part of my GSoC proposal. I did some homework and contrasted the bigint api in Boost and Java and found some interesting things that could be done. Boost.bigint was written by zeux and he used GMP bigint's features writing the Boost.bigint code around it. I think I could learn and analyse more after having a look at GMP bigint. After all, I think Boost.bigint should be more exhaustive. -------------------------------------------------------------------------------------------------------------------------------------------------------------- Feature Boost bigint Java BigInt -------------------------------------------------------------------------------------------------------------------------------------------------------------- Constructors from | int | byte[] #byte array with 2's complement representation of the BigInt. | unsigned int | int bitlen, int certainity #random BigInt with given bit length | int64_t | | uint64_t | | char *, int base | String | string& str, int base | String, radix -------------------------------------------------------------------------------------------------------------------------------------------------------------- *Conversion from string of digits to bigint is present. However conversion from/to byte-array(2's complement notation) to/from bigint isn't. Also the generation of a random arbitrary precision bigint should be done. int bitCount() #return the no of bits in 2's complement of the bigint; int bitLength() #no of bits excluding the sign bit double doubleValue() #casting bigint to double must be done. #even casts to int, uint and int64_t, char * must be done.* -------------------------------------------------------------------------------------------------------------------------------------------------------------- Arithmetic Operators += In Java, add, subtract, multiply, etc., | -= | *= | /= | %= | |= | &= | ^= #xor | <<= | >>= | ++ #postfix & prefix | -- #postfix & prefix -------------------------------------------------------------------------------------------------------------------------------------------------------------- Unary Operators + - BigInteger[] negate() ~ BigInteger[] not() ! #is zero < int compareTo(BigInteger val) <= BigInteger max,min(BigInteger val) > >= == != -------------------------------------------------------------------------------------------------------------------------------------------------------------- *These are some bit manipulators BigInteger clearBit(int n) #not in Boost.bigint #even setBit & toggleBit could be done, with a feature of changing the precision of the bigint. BigInteger[] testBit(int n) #also bit testers l* -------------------------------------------------------------------------------------------------------------------------------------------------------------- Binary Operators + BigInteger add(BigInteger val) - * BigInteger multiply(BigInteger val) {bigint lhs, int rhs} {int lhs, bigint rhs} / BigInteger divide(BigInteger val) % BigInteger mod(BigInteger val) , BigInteger modPower(BigInteger val) | BigInteger or(BigInteger val) & BigInteger and(BigInteger val) ^ BigInteger andNot(BigInteger val) << BigInteger shiftLeft(int n) >> BigInteger shiftRight(int n) -------------------------------------------------------------------------------------------------------------------------------------------------------------- Math function overloads abs(bigint_base) BigInteger abs(int exponent) pow(bigint_base, uint64_t) BigInteger pow(int exponent) div(bigint_base lhs, bigint_base rhs, bigint_base& remainder) BigInteger[] divideAndRemainder(BigInteger val) sqrt(bigint_base) ----------No Java version for BigInterger------------ -------------------------------------------------------------------------------------------------------------------------------------------------------------- *BigInteger gcd(BigInteger val) #GCD would be one of the most important requirements for bigint #Also the Java function of bool ProbablyPrime() is very interesting and would be challenging to implement.* -------------------------------------------------------------------------------------------------------------------------------------------------------------- -- Problem is a phenomenon indicating lack of thought. Swagat Konchada

3 2

Debugging Visualizers
by Alex Miller 25 Mar '10

25 Mar '10

quoted from the ongoing "5 Observations" thread: On Tue, Mar 23, 2010 at 4:36 PM, Steven Watanabe <watanabesj(a)gmail.com>wrote: > > Perhaps you would find this useful: > https://svn.boost.org/trac/boost/wiki/DebuggerVisualizers > > It is mentioned there that the same thing could be done for GDB,etc. However, I can't seem to find anything of the sort by googling (although it's very possible I'm just searching poorly). Could anyone point me towards where docs on how to do this could be found at?

2 2

filesystem::create_directories error
by Zachary Turner 24 Mar '10

24 Mar '10

I'm trying to use boost::filesystem::create_directories() with a path of the form \\?\Volume{Guid}\foo on windows. This seems to break the filesystem library because it doesn't understand the path syntax. when recursing up the parents it removes the slash at each level, so it ends up calling boost::filesystem::exists(L"\\?\Volume{Guid}") which always returns false, I think because GetFileAttributes() requires that paths in this syntax end with a trailing \, whereas the trailing \ has been removed. I'm tempted to fix this, but I'm sure this algorithm is fragile and any change I apply is likely to break another case. Does anyone have any suggestions on how to fix this? Thanks

3 4

[log] review part 1
by Steven Watanabe 24 Mar '10

24 Mar '10

AMDG I mostly have documentation notes at this point. Andrey, since I have so many, and they're mostly fairly minor, would it be better if I made a patch for the documentation source? I think newbies should probably be replace globally with new users, since I kind of feel that the term newbie is somewhat derogatory. http://boost-log.sourceforge.net/libs/log/doc/html/log/moti.html: ================================================================================ Mismatched number: Most of the time ***applications*** ... to monitor ***its*** execution... The beginning of the second paragraph could be improved: "This is where logging may help. The application stores all essential information of its run time to log, and once something goes wrong this information can be used to analyze program behavior and make necessary corrections." Here's my suggestion: "This is where logging can help. The application stores all the essential information about its execution to a log, and when something goes wrong this information can be used to analyze the program's behavior and make the necessary corrections." "out-of-box" should be "out-of-the-box" This phrase sounds rather clunky to me: "...along with public interfaces ready to be used to extend the library." This too: "A user should be able to extend functionality of the library with regard to collecting and storing information into logs." "The library should make as least performance impact..." should be "The library should have as little performance impact..." http://boost-log.sourceforge.net/libs/log/doc/html/log/how_to_read.html: ================================================================================ In the beginning of the second paragraph, I don't like the phrase "to have the first glance on" How about something like "...to get a feel for the library's capabilities..." "The tutorial gives the overview of the library features..." Suggestion: "The tutorial gives an overview of the library's features..." "The simple form typically describes the most common and easy way to do the task and it is being recommended to be read by newbies." Suggestion: "The simple form typically describes the most common and easy way to do the task and is recommended for new users." "The advanced form usually gives an expanded way to do the same thing but with ability to do some extra customization and in-depth explanation." I would like a definite article before "ability" and I would also like "and in-depth explanation" to be placed differently so that it doesn't sound like you're saying that the user has the ability to do in-depth explanation. "This form may come handy for more experienced users and should generally be read if your needs are not satisfied with the easy way." Suggestion: "This form may come in handy for more experienced users and should generally be read if the easy way does not satisfy your needs." "This part gives description of other tools..." should be "This part gives descriptions of other tools..." "This chapter is better to be read on per-case basis." Suggestion: "This chapter is best read on a case by case basis." "there is a reference which gives the formal description of library components. " The work "description" should be plural, "descriptions". "For simplicity in the code snippets in this documentation it shall be assumed that the following namespace aliases were defined" Suggestion: "To keep the code snippets in this documentation simple, the following namespace aliases are assumed to be defined" "Aside from these namespaces the library also provides boost::log::experimental namespace." Suggestion: "In addition to these namespaces the library also provides the boost::log::experimental namespace." "and thus are not advertized for productional usage" The word "productional" should be "production" http://boost-log.sourceforge.net/libs/log/doc/html/log/supported_compilers.…: ================================================================================ "The library should build and work with a reasonably well-compliant compiler" delete "well-" http://boost-log.sourceforge.net/libs/log/doc/html/log/installation.html ================================================================================ "The library has the compiled part which should be built as described in the Getting Started article." Suggestion: "The library has a separately compiled part which should be built as described in the Getting Started guide." For BOOST_LOG_NO_THREADS "Has effect on both the library compilation and user's code compilation." Suggestion: "Affects compilation of both the library and users' code." "The macro is automatically defined if no threading support detected." add "is" before "detected" For: BOOST_LOG_USE_CHAR Same as the first comment for BOOST_LOG_NO_THREADS. (This appear many times, I won't repeat it again) For: BOOST_LOG_USE_WCHAR_T "it is assumed the both character types support is enabled" Suggestion: "support for both character types will be enabled" "Defining only one of them allows to significantly reduce binary size of the library." Suggestion: "Defining only one of them significantly reduces the binary size of the library." For BOOST_LOG_NO_QUERY_PERFORMANCE_COUNTER: "If defined, disables support for QueryPerformanceCounter API" Suggestion: "If defined, disables support for the QueryPerformanceCounter API" For BOOST_LOG_USE_NATIVE_SYSLOG: "Has effect on the library compilation stage." Suggestion: "Affects only the compilation of the library." (repeated later as well) "If for some reason the support for native SysLog API is not detected, define this macro to forcibly enable support for native SysLog." Suggestion: "If for some reason support for the native SysLog API is not detected automatically, define this macro to forcibly enable it." For BOOST_LOG_NO_SETTINGS_PARSERS_SUPPORT: "If defined, all facilities related to settings parsing are not built." Suggestion: "If defined, none of the facilities related to the parsers for settings will be built." "You may define configuration macros..." should be "You can define configuration macros..." http://boost-log.sourceforge.net/libs/log/doc/html/log/defs.html ================================================================================ For Log record: I don't like the expression "A single pack of information," although I can't think of anything better off hand. "that is candidate to be put into log" Suggestion: "that is a candidate to be put into the log" For Attribute "functional objects" should be "function objects" "which return the actual attribute value upon invoking" Suggestion: "which return the actual attribute value when invoked" For Log sink: "collected from user's application" should be "collected from the user's application" "It is sink's nature that defines where..." Suggestion: "The sink defines where..." For Log source "An entry point for user's application..." should be "An entry point for the user's application..." "upon user's request" should be "upon the user's request" For Log formatter "functional object" should be "function object" "...that forms up the final shape of the textual output" is awkward. "Some sinks, like binary logging sink" should be "Some sinks, like the binary logging sink" For Logging core "The global entity that maintains connection between" should be "The global entity that maintains the connection between" "It is mainly used on the logging library initialization stage." replace "on" with "in." http://boost-log.sourceforge.net/libs/log/doc/html/log/design.html ================================================================================ I htink "scheme" with "figure" "The library provides configuration facilities to leave only one needed version of the library to be compiled." Suggestion: "The library provides configuration facilities to compile only the version of the library needed." "For example, if your application is in critical state" should be "For example, if your application is in a critical state" "so that user sees an error message..." should be "so that the user sees an error message..." "This allows to use the library" Suggestion: "This allows use of the library" "...require users to use loggers to write logs" "use" and "log" are used too many times here. "The more generic term "log source" is used to designate the entity" Suggestion: "The more generic term "log source" designates the entity" "You may see on the scheme that the" suggestion: "You can see on the scheme that the" "and allows to quickly wipe away unneeded log records" suggestion: "and allows quickly wiping away unneeded log records" anyway, don't split infinitives. "The sink-specific filtering allows to direct log records to particular sinks." Suggestion: "The sink-specific filtering allows log records to be directed to particular sinks." "Backends, on the opposite" suggestion: "Backends, on the other hand" "most probable places of the library extension" suggestion "most likely places for extending the library" "Along with the described above primary facilities" should be "Along with the primary facilities described above" ================================================================================ Issues: Instead of compiling a narrow or wide library, why don't you use libboost_log and libboost_wlog? I agree with other comments that I saw about Attribute being a poor choice for what it does. I would prefer that the term "Attribute" should be used for what you call an "Attribute Value," and that there should be a different term, like "Attribute Extractor" for what you call an "Attribute." In Christ, Steven Watanabe

3 10

[ASIO] Create SSL stream from native socket?
by Marcel Fransen 24 Mar '10

24 Mar '10

Hi, I would like to create an ssl stream for an already accepted native socket, just like is possible with basic_stream_socket< tcp >. How should this be done? Currently there is only one ssl::stream constructor which takes one parameter that is passed to the basic_stream_socket: template <typename Arg, typename Context_Service> explicit stream(Arg& arg, basic_context<Context_Service>& context) : next_layer_(arg), service_(boost::asio::use_service<Service>(next_layer_.get_io_service())), impl_(service_.null()) { service_.create(impl_, next_layer_, context); } To be able to create an ssl stream from an existing socket we would need a constructor which passes three parameters to the basic_stream_socket like this: template <typename Arg1, typename Arg2, typename Arg3, typename Context_Service> explicit stream(Arg1& arg1, Arg2& arg2, Arg3& arg3, basic_context<Context_Service>& context) : next_layer_(arg1, arg2, arg3), service_(boost::asio::use_service<Service>(next_layer_.get_io_service())), impl_(service_.null()) { service_.create(impl_, next_layer_, context); } Would it be a problem to add constructors that passes two and three parameters to the basic_stream_socket or can this be done in another way? Kind regards, M. Fransen _________________________________________________________________ New Windows 7: Simplify what you do everyday. Find the right PC for you. http://windows.microsoft.com/shop

2 1

Re: [boost] GSOC 2010 Boost.Graph
by Chinmaya Poswalia 24 Mar '10

24 Mar '10

Topology Generators : 1) along with path, cycle, star how about also adding bus ,mesh and hybrid topologies. 2) we can also include dual, complement , line and power of a graph.

1 0

Re: [boost] GSOC 2010 Boost.Graph
by Chinmaya Poswalia 24 Mar '10

24 Mar '10

Bindings to Python : there are tools as SWIG as language bindings. is it good employ them in making the bindings. Could anyone please suggest some tutorial for binding creation. I was not not able to find on google

1 0

Willing to Join GSOC 2010
by Xin Shuai 24 Mar '10

24 Mar '10

Hi: I'm interested in your Boost.Graph project. I think my current graph theory related research as well as C++ and python programming experiences makes me fit for the project. I'm wondering who's the mentor for the Boost.Graph project and I hope he/she can give me useful suggestions about the project. -- Xin(David) Shuai PhD of Complex System in School of Informatics & Computing Indiana University Bloomington 812-606-8019 The way to success is to do as much as important things, and as less as unimportant things, as you can...

2 1

[GSoC]I am interested in Boost.Graph
by doraemonok 24 Mar '10

24 Mar '10

My name is Rui Diao. I am a student of Graduate University of Chinese Academy of Sciences. My major is Computational Mathematics. I have never contributed to any open software project, but only spread the open source spirit to the people around me and join some open source groups. The only contribution of my source file is developing a Client of IP Gateway of My University by Qt open source version. Contributing to Boost C++ Libraries is an interesting and challenging job, and also, of course, fantastic. I am interested in one project of Boost.Graph : Graph Connectives. I like Graph Theory very much. I have experiences on coding (and teaching the friends in open software association of my university) some algorithms about Graph Theory: Dijkstra, Floyd, Bellman Ford, Ford Fulkerson, SAP, Kuhn-Munkres, etc. I have learned a lot in "How to finish an excellent project" during the internship of Microsoft Research Asia. Moreover, I am familiar with Mathematica which has similar function with Boost.Graph. I am very familiar with STL, but seldom use Boost. I just have experiences on using Boost.Regex before. I have checked out the source code by Subversion and began to read the part of Boost.Graph recently. The Boost.Graph library is missing connectives which contains Graph Join, Graph Union, Graph Product, Graph Intersection, Graph Difference, Graph Sum, Graph Product, Line Graph, etc. I think the algorithms may be not too difficult to me, but how to code with "Boost Style" (of course not only the code style) is a problem. I will try my best to finish the challenging work. I think may be there is some mentor can give me some advices or suggestions. Thank you all. Rui Diao

2 1

[log] Boost.Log formal review
by barend 24 Mar '10

24 Mar '10

Hi, This is my review of Boost.Log submitted by Andrey Semashev. > Please explicitly state in your review whether > the library should be accepted. I've been doubting about this for a few days. When I started my review, by trying to use the library, I discovered that the library is not header-only. I had thought that a logging library should be lightweight and had therefore expected only headerfiles. I then tried the library from John Torjo from 2007 but it is not header- only neither, so no reason to favour that one (I didn't dive into it further). Because of some messages on the list, a.o.: > I think that any reasonable log library must be compiled > to it's own lib due to the intermodule singleton requirement I realized that it is indeed useful to have a non-header-only option as well. The answers of Andrey were satisfactory, a.o.: > If we have a list of places in Boost where logging may be applied, > perhaps we could compile a set of requirements for such a lightweight > wrapper. When we have it, it would be easier to tell, whether Boost.Log > fits the role or not, or whether the wrapper should be part of it or a > separate submission. I'd be interested to hear from the library authors > on this topic. And I found in the Boost.Log documentation, TODO-list: > Think over a header-only configuration. Perhaps, with a reduced > functionality. So, good. Then I started the real review and I started to like the library, it is definitely useful, is configurable, trivial logging is quite simple. It also contains very useful non-trivial features such as writing to the Windows Event Log and alarm critical states as balloon tips. So I finally decided to give my YES vote, contingent on the condition that a lightweight header-only configuration, e.g. single-threaded, single-module, will be available for library writers. Some more about this below. --------------------------------------------------------------------- > What is your evaluation of the design? I like the options, the trivial logging, multiple back-ends, modularity and extensibility. I didn't have a detailed look to the design but in general it looks good to me. > What is your evaluation of the implementation? I didn't have a detailed look either. I glanced through the sources and the implementation is looking neat. I wonder why the class "basic_slim_string" is necessary, to me it sounds very strange why a task as logging needs an own string implementation. However, I didn't have the time to dive into it and didn't ask questions on this on the list. > What is your evaluation of the documentation? The documentation is good. Pages like design overview, tutorial, installation are easy to follow. The tutorial pages however contain some omissions and you have to refer to the examples to see what is missing. I mean here the chapter "Trivial logging with filters" which seems to give a complete example, but misses the namespace aliases, two of them would have been enough. > What is your evaluation of the potential usefulness of the library? Very useful, definitely, for applications and for libraries. > Did you try to use the library? With what compiler? Did you have any > problems? Yes, I used it using Visual C++ 2008 Express Edition. Because Boost.Log is not header-only, and I don't have the Boost libs compiled on my machine (don't ask me why, I never have them), I had several issues which other reviewers probably didn't run into. The defines _CRT_SECURE_NO_WARNINGS and _SCL_SECURE_NO_WARNINGS were necessary to surpress M$ warnings. The define BOOST_ALL_NO_LIB is of course necessary to build it like I did, and it works for Boost.Log. The compiler complained about a missing simple_event_log.h by event_log_backend.cpp, so I drafted it by hand, but I later saw that it is documented and you should neatly use the message compiler, so OK. After adding some Boost source files from thread, filesystem, regex and system it worked, datetime was not necessary. A complete build (including all mentioned sources) costs about 2 minutes. The tutorial did work (see message above on filtering, adding namespace aliasses was necessary) and I experimented with some things, many options seems very useful to me such as the log format, automatic date time, log file rotation, log file max size, etc. etc. I like the streaming feature (so for me printf is not necessary). I have some reservations about the compiler support: GCC 3.4.5, the default on Linux and MinGW, is not supported and for a task as logging this seems to me as a disadvantage. > How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? About five to six hours spread over some days. > Are you knowledgeable about the problem domain? Yes, I always need logging. In our library at Geodan we built logging as a singleton in 1995. We rewrote it to a logging-over-DLL's in 2000, but these two were not 10% as sophisticated and complete as this logging library is. So yes, these things were not header-only neither. --------------------------------------------------------------------- So back on the logging for libraries. If Boost libraries which are header-only will start to use this library, without protection, thousands and thousands of project files and makefiles worldwide will be broken. This answer: > If an existing header-only library starts using the Boost.Log library > we'll need to update the makefiles. This is a reasonable cost (not from Andrey)is therefore not satisfactory to me. This answer: > Which probably means that the decision is with the author(s) of each > individual library. (from the review manager) surprised me a bit, I think that in a library under review such an important thing may certainly be discussed, per library. However, as said, it is not a reason to vote no, because the rest of the library is quite good. A small macro (sorry) wrapper would already do most of the trick, and avoid breaking project files: #if defined(BOOST_ALL_LOG) || defined(BOOST_GEOMETRY_LOG) #define BOOST_LOG_GEOMETRY(o, s) BOOST_LOG_TRIVIAL(o) << s #else #define BOOST_LOG_GEOMETRY(o, s) #endif Where it can be called in libraries as: BOOST_LOG_GEOMETRY(info, "Log line with a value " << 3); This is inspired on the general define "BOOST_ALL_NO_LIB" and library- specific define "BOOST_LOG_NO_LIB". This small wrapper would really be useful, at least for us, and replace the #ifdef BOOST_GEOMETRY_DEBUG lines which are currently in our Boost.Geometry library. This is zero cost when one of the macro's BOOST_ALL_LOG or BOOST_GEOMETRY_LOG is not defined (by default it is not), and contains much functionality of Boost.Log as filtering, rotation, etc, when one of these macros is defined. Of course it can be enhanced or there are better solutions. Anyway, a lightweight solution will not be difficult. --------------------------------------------------------------------- So thanks Andrey for submitting this library, thanks Volodya for managing the review, and I hope it will be accepted with a lightweight header-only configuration included. Regards, Barend

2 1

interprocess
by Jan Stetka 24 Mar '10

24 Mar '10

Has anyone else noticed that a named_mutex gets destroyed after a windows xp computer goes into hibernate?

4 3

Problem regarding downloading Boost 1.42.0
by Wasik Mursalin Rushafi 24 Mar '10

24 Mar '10

Hi, I am trying to download the latest boost library from here<http://sourceforge.net/projects/boost/files/boost/1.42.0/>but failing. is there any problem? isn't it available or I am the only one facing this problem? -- Rushafi

2 1

[log] cygwin gcc-4.3.2 compilation/run-time errors
by vicente.botet 23 Mar '10

23 Mar '10

Hi Andrey, I have found thre kind of errors while compiling Bost.Log with cygwin gcc-4.3.2 * WHAR related * SYSLOG related Do you know if we can install syslog on cygwin? * SETTING related (reading from a configuration file) I have not yet analyzed the SETTING errors. I will see later. I have prefixed any modified line with the BUG WCHAR/SYSLOG/SETTING on the attached patches. After all this I have reached to compile the whole library with tests and examples. Only 2 test passed and There are yet some link warnings that could be suspect and a lot of runtime errors (see below) It would be great if you can apply some of the modification on the attached patch (of course not the Jamfiles) Best, _____________________ Vicente Juan Botet Escribá gcc.link ../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.exe Info: resolving vtable for std::exception by linking to __imp___ZTVSt9exception (auto-import) Info: resolving vtable for std::bad_cast by linking to __imp___ZTVSt8bad_cast (auto-import) Info: resolving std::cout by linking to __imp___ZSt4cout (auto-import) Info: resolving std::cerr by linking to __imp___ZSt4cerr (auto-import) Info: resolving typeinfo for std::runtime_error by linking to __imp___ZTISt13runtime_error (auto-import) Info: resolving std::ios_base::in by linking to __imp___ZNSt8ios_base2inE (auto-import) Info: resolving std::ios_base::out by linking to __imp___ZNSt8ios_base3outE (auto-import) Info: resolving typeinfo for std::bad_alloc by linking to __imp___ZTISt9bad_alloc (auto-import) Info: resolving typeinfo for std::bad_cast by linking to __imp___ZTISt8bad_cast (auto-import) Info: resolving typeinfo for std::bad_typeid by linking to __imp___ZTISt10bad_typeid (auto-import) Info: resolving typeinfo for std::bad_exception by linking to __imp___ZTISt13bad_exception (auto-import) Info: resolving typeinfo for std::logic_error by linking to __imp___ZTISt11logic_error (auto-import) Info: resolving typeinfo for std::exception by linking to __imp___ZTISt9exception (auto-import) Info: resolving typeinfo for std::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> > by linking to __imp___ZTISt19basic_ostringstreamIcSt11char_traitsIcESaIcEE (auto-import) Info: resolving typeinfo for std::basic_ostream<char, std::char_traits<char> > by linking to __imp___ZTISo (auto-import/usr/bin/ld: warning: auto-importing has been activated without --enable-auto-import specified on the command line. This should work unless it involves constant data structures referencing symbols from auto-imported DLLs.) testing.capture-output ../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.run ====== BEGIN OUTPUT ====== EXIT STATUS: 53 ====== END OUTPUT ====== PATH="//bin://lib://lib32://lib64:/boost_1_41_0/bin.v2/libs/date_time/build/gcc-4.3.2/debug/threading-multi:/boost_1_41_0/bin.v2/libs/filesystem/build/gcc-4.3.2/debug/threading-multi:/boost_1_41_0/bin.v2/libs/log/build/gcc-4.3.2/debug/threading-multi:/boost_1_41_0/bin.v2/libs/regex/build/gcc-4.3.2/debug/threading-multi:/boost_1_41_0/bin.v2/libs/system/build/gcc-4.3.2/debug/threading-multi:/boost_1_41_0/bin.v2/libs/test/build/gcc-4.3.2/debug/threading-multi:/boost_1_41_0/bin.v2/libs/thread/build/gcc-4.3.2/debug/threading-multi:$PATH" export PATH "../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.exe" > "../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.output" 2>&1 status=$? echo >> "../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.output" echo EXIT STATUS: $status >> "../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.output" if test $status -eq 0 ; then cp "../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.output" "../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.run" fi verbose=0 if test $status -ne 0 ; then verbose=1 fi if test $verbose -eq 1 ; then echo ====== BEGIN OUTPUT ====== cat "../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.output" echo ====== END OUTPUT ====== fi exit $status ...failed testing.capture-output ../../../bin.v2/libs/log/test/attr_attribute_values_view.test/gcc-4.3.2/debug/threading-multi/attr_attribute_values_view.run...

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Re: [boost] 5 Observations - My experience with the boost libraries
by Brian Wood 23 Mar '10

23 Mar '10

Tom Brinkman writes: >> Exceptions are a fact of C++ life. You can't avoid them if for no other >> reason than std::bad_alloc, unless you don't allocate from the free store. > > Not true, there are no-throw versions of std::new. > > In any event, my point is that c++ exception handeling should be optional. > Boost libraries need to be updated to reflect this. I used to support both return codes and exceptions. Eventually I gave up supporting return codes, because attempting to support both was quite difficult. Dropping support for return codes was kind of a difficult decision for me -- but after not being able to think of another project that supports both, I decided to only support exceptions. Since making that decision, I feel I'm able to make faster progress in other areas. Do you know of any libraries that support both return codes and exceptions? -- Brian Wood Ebenezer Enterprises http://webEbenezer.net (651) 251-9384

1 0

Re: [boost] GSOC 2010 Boost.Graph
by Chinmaya Poswalia 23 Mar '10

23 Mar '10

Please comment on the following topics Hierarchical Layout Algorithms : 1) what is being implemented in spring based layout or what are the files(headers files) in the boost. Computer Vision Algorithm : 1) suggest me some examples regarding the "Implementing a specialized graph type for grids would also be needed in order to avoid storing the graph topology explicitly". I am not getting the point correctly.

2 1

[Review] ITL review extended until March 7th
by Hartmut Kaiser 23 Mar '10

23 Mar '10

Hey all, After getting the approval from our review wizards we decided to extend the review period of Joachim Faulhabers ITL library until March 7th, 2010. That should give everybody some more time to finish their reviews. Regards Hartmut --------------- Meet me at BoostCon www.boostcon.com

4 4

[Boost.Locale] Questions (was New Release)]
by Alexander Lamaison 23 Mar '10

23 Mar '10

Artyom wrote: >> I sent this to the list via Gmane but >> its stuck in the moderation queue so >> I'm sending it to you personally: >> > You probably should register to boost mailing list directly? > I did that too but it said because it was my first post to the list (I usually hang out in boost.user not .devel) it had to be moderated. It's been days now :( >> I compile my code with MSVC8: >> > > I hadn't tested this library with MSVC8 (2005), I would be glad if > you can build it and run unit-test (if you using nmake then > run "nmake test") If you are working with solution there should be > an option. > I did this and everything passed. Though when I run examples on the command line the output includes much that isn't readable. Is this because the terminal doesn't handle the codepages correctly? > So I would know that MSVC 2005 is fine as well. Once you run the > test, can you please send me: your os version and ICU Version so I can > update the tested platforms list? > I'm using Vista 32-bit with ICU 4.2.1 I've just started internationalising my project (Swish http://swish.sourceforge.net) using Boost.Locale so I may have many questions for you as I go along. I hope this will helps Boost.Locale as much as it helps me. Firstly, I'm trying to decide which format() to use: boost::format or boost::locale::format. If I don't use currencies or dates and always use the global locale, are there any advantages to boost::locale::format? The tutorial says of boost::format "It knows nothing about new Boost.Locale manipulators". I don't understand what this means. Which new manipulators? I notice that boost::locale::format has a constructor that takes a message as an argument and then does something internally that depends on the value of _translate but I don't understand why. boost::format can be used like this: boost::format(translate("Id string %1%")) % arg so what does the extra boost::locale::format constructor allow that this doesn't? Also I make gettext enforce correct translation of format strings by passing --boost to xgettext. This reports an error if the format tokens, %1% etc., don't match in the original and translated strings. Changing these to {1} etc. in boost::locale::format means this no longer works. What was the tecnical motivation for this change? My second question relates to the directory structure for the .mo files and applies to gettext as much as to boost::locale (I'm new to gettext too). Why do they expect to find the files at lang_ctry/LC_MESSAGES/proj.mo? This makes sense when translations for many projects are stored in a common location such as |/usr/share/locale/ but on Windows this wouldn't be likely. I plan to store my translation in my program's installation directory and wish I could just put them in a flat directory: translations/ar.mo translations/en_GB.mo etc. Is it possible to make the lookup fallback to this scheme or even make the scheme customisable? Many thanks for this excellent library. Alex |

2 1

Re: [boost] GSOC - Boost Libraries - BIGING
by swagat konchada 23 Mar '10

23 Mar '10

Hello everyone! On Tue, Mar 23, 2010 at 2:20 AM, Andrew Sutton <andrew.n.sutton(a)gmail.com>wrote: > > Hi Swagat, > > We are glad that you are interested in submitting a proposal for Boost in > this year's GSoC program. However, it's hard to comment on your proposal > unless you provide details about what you intend to do over the course of > the summer. GSoC is a very competitive program, and Boost is particularly > selective about awards. > > Please see [1] for ideas on how to write a good proposal. > > Thanks to Andrew Sutton for his kind reply and the relevant link. They have been of great use to me. I had a look around in the Boost Sandbox and I found a BigInt implementation done by zeux during GSoC 07. I had a look at the code and I wanted to know its deficiencies. I'm interested in proposing a BigDecimal implementation that is building on this code. There are 2 questions that I wanted to ask the list before moving further on this track: 1. Is there sufficient interest for a BigDecimal proposal on the lines of the Java implementation of BigDecimal (or has there been some prior work that can be used as a foundation?) 2. What are the deficiencies of BigInt that have prevented its inclusion into the Boost distribution so as to address the same as part of my GSoC proposal. Thanking you, Yours sincerely, -- Problem is a phenomenon indicating lack of thought. Swagat Konchada

1 0

[log] Boost.Log formal review closing down
by Vladimir Prus 23 Mar '10

23 Mar '10

Boosters, just a a friendly reminder that the formal review of the Boost.Log library, written by Andrey Semashev, is nearly the end, with about 24 hours remaining. If you planned to submit a review but have not done so, it's just about the time! The documentation for the current version is available at: http://boost-log.sourceforge.net The downloads are at: http://sourceforge.net/projects/boost-log Here are the important points: 1. All comments are appreciated. Even if you don't have the time for in-depth study of everything, comments on parts of the library are welcome. In particular, if you are already using logging in your applications and have specialized requirements, you might want to directly check how the proposed library handles them. 2. The reviews and all comments should be submitted to the developers list, boost(a)lists.boost.org and the email should have "[log]" prefix in the subject to make sure it's not missed. The deadline for reviews is 23:59, March 17, PST = 2:59, March 18, EST = 7:59 March 18, GMT = 10:59, March 18 MSK 3. Please explicitly state in your review whether the library should be accepted. 4. The general review checklist is provided below: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Thanks, Volodya

7 48

GSoC 2010 idea
by Viktar Sialiuk 23 Mar '10

23 Mar '10

Dear the Boost developers, I'd like to participate in GSoC 2010 event. Could you please review my idea. I very much appreciate your opinion about this. We have ability to generate OOP wrappers by the XSD schema in the popular languages( such as Java or C#) but have not in the C++. With such a tool we will be able to generate C++ classes or structures with functionality of serialization/deserialization from/to XML. Implementation of SOAP webservice client will be easy task( or writing webservice itself). We can create tool (for example xsd2cpp) under boost.xml library and include it to the boost.build. Thanks, Viktar Sialiuk

6 10

[GSoC] Introduction and questions
by Felipe Tanus 23 Mar '10

23 Mar '10

Hi, My name is Felipe Tanus and I would like to participate (for the first time) of GSoC in this project, specifically in the boost.process library. While my proposal is not ready, you can check a little about me in my website[1]. I already downloaded and had a look in the code, and read the documentation provided. This turned me even more excited about the project. To be able to do a proper schedule and define milestones, I need to study more about of POSIX and Windows process architectures, and what the APIs let me to do. For this, I have been reading some man pages (unistd, signal...) and the MSDN documentation. My first question about this project is exactly about that: Do you have any suggestions about where can I find out about this matter? I would like it to be from a reliable source. You can reach me in IRC, on freenode's boost channel as "fotanus", and by this e-mail. Thanks in advance, -- Felipe de Oliveira Tanus E-mail: fotanus(a)gmail.com Blog: http://www.itlife.com.br [1]: Site: http://www.inf.ufrgs.br/~fotanus/ ----- "All we have to decide is what to do with the time that is given us." - Gandalf

3 5

[Boost][Gsoc 2010] Boost.Graph project
by Jakub Tlałka 23 Mar '10

23 Mar '10

Hello, I would like to engage in the Boost.Graph project. I have an idea of a graph architecture for simulating various processes in networks. I think it would be useful in the Network Workbench. It would consist of network graph generator. It is something like topology generator, but apart from inducing topologies, It should also induce given features characteristic to a certain network (ie density, or distribution of some vertices parameters over a graph). In addition there would be some iterate function, that would simulate the processes given by some dependencies between vertices or edges. That's the simple draft of the idea. I don't have much experience in this kind of projects so I'm not quite sure about the possibility/necessity of the idea. I'm interested in graph theory, I have algorithmic experience connected with Informatics Olympiad and I'm ready to spend my time expanding the boost library. I'm also ready to engage in the other listed problems regarding Boost.Graph. I would be very grateful for every comment, this is my second open source project and I'm willing to gain my experience in this field, and contribute not necessarily in connection with gsoc. Best wishes, Jakub Tlałka

2 1

Thread-safe singleton pattern
by Andrew Chinkoff 22 Mar '10

22 Mar '10

I propose thread safe singleton pattern implementation (see http://www.research.ibm.com/designpatterns/pubs/ph-jun96.txt) I have attached "singleton.hpp" to this letter. Below is the test program: #include <stdio.h> #include <singleton.hpp> class A : public boost::Singleton<A> { // // Only Singleton class can create and delete us! // SINGLETON_IS_MY_FRIEND; public: void foo(){ printf("foo!\n"); } A(){ printf("A()\n"); } ~A(){ printf("~A()\n"); } }; void main() { // It is not compiled: //A a = A::Instance(); // That is exactly as it should be used: A::Instance().foo(); } Test program outputs: A() foo! ~A() My question: Does Boost community think that boost::Singleton is convenient (or successful) solution?

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Re: [boost] GSOC - Boost Libraries
by Andrew Sutton 22 Mar '10

22 Mar '10

> I am Swagat and C++ is my passion. > Hi Swagat, We are glad that you are interested in submitting a proposal for Boost in this year's GSoC program. However, it's hard to comment on your proposal unless you provide details about what you intend to do over the course of the summer. GSoC is a very competitive program, and Boost is particularly selective about awards. Please see [1] for ideas on how to write a good proposal. Andrew Sutton andrew.n.sutton(a)gmail.com [1] https://svn.boost.org/trac/boost/wiki/SoCHints

1 0

Questions about Graph Project
by Liang Dong 22 Mar '10

22 Mar '10

Hi, I am reading the Graph Project's source code. I find there are page rank algorithm, but there is no HITS algorithm and samba. I am curious that if this would be a good topic or everyone just endorse pagerank? best, Liang Dong

2 1

[log] std::endl manipulator does not work, intentional
by Andreas Huber 22 Mar '10

22 Mar '10

Hi Andrey On VS2008, this code ... #include <boost/log/trivial.hpp> #include <ostream> int main() { BOOST_LOG_TRIVIAL(trace) << "This is a" << std::endl << "multiline message"; return 0; } ... fails compilation with the following error: error C2679: binary '<<' : no operator found which takes a right-hand operand of type 'overloaded-function' (or there is no acceptable conversion) Now I do realize that "\r\n" would be a better choice here, as the flushing that comes with std::endl is not necessary. However, some developers in our team seem to prefer std::endl nevertheless. So, the question is: Is this intentional or just an oversight? BTW, only std::endl, std::ends and std::flush don't work, all the other manipulators do. Thanks, -- Andreas Huber When replying by private email, please remove the words spam and trap from the address shown in the header.

2 1

GSOC - Boost Libraries - BIGINT
by swagat konchada 22 Mar '10

22 Mar '10

Hello! I am Swagat and C++ is my passion. I am a student at IIT Roorkee. I would love to work for Boost libraries in GSOC or any other manner. I came to know about GSOC recently. I hope I am not late. Though I initially thought of working for cppnetlib, after seeing the ideas given in the boost gsoc’10 page, I think the project I would like to work the most would be to implement BigInt. I have suffered many times trying to work with big integers, though some code is available on the Internet. A standardized library for BigInt if made enough programmer-friendly would be wonderful. As a programmer who often participates in online competitions, BigInt feature would have been of great use to me and working on it would be more than fun! Also I am free for the summer when I would be staying at my campus the whole time, without distractions. I have attached my resume above. Please comment. ---------------------------------------------------------------------------- A problem is a phenomenon indicating lack of thought. http://letmeseeswagat.blogspot.com/

1 0

GSoC draft proposal: Heaps & Queues library
by Andre Ferreira 22 Mar '10

22 Mar '10

This is only a draft, not the final proposal. Personal Details: Name: André Martins Ferreira Email: greiskul(a)gmail.com University: Universidade Federal do Rio Grande do Sul < www.ufrgs.br > Course: Computer Science Degree Program: Bachelor of Computer Science Availability: About 30 hours a week will be devoted to the project, more if nescessary. Start Date: April 1st End Date: not yet decided Factors of influence: I live in the Southern Hemisphere, so the Summer of Code will be during Winter. While I will have a winter vacation where my attettion will be 100% devoted to the project, it will only last about a month, from July to August. During the rest of the time I will study in the morning, and work on the project on my free time, which luckily this semester entails all afternoons. I have worked during school time in previous semesters, and know that it's possible. Background Information: I am a brazilian computer science student, my course has 9 semesters, I am currently in the 7th. I have been programming for the last 5 years, mostly in C++ but also in Scheme, Lua, and many other languages. I've had an intership in developing parallel programs using MPI, and more recently in supporting an ERP written in C++. My main interest is in algorithms and data structures, but I'm also interested in functional programming languages. My experience with heaps comes from my university classes, Cormen's Introduction to algorithms book, various online sources and personal experimentation. While I have implemented heap data structures before (binary, binomial, skew), I have never integrated them in a single package generic package before and I'm looking foward to learn from it. I would rate my experience in the following technologies this way: 4 C++ 4 C++ Standard Library 2 Boost C++ Libraries 3 Subversion I use mainly Eclipse and Geany for development, but I have also done projects with Visual Studio. For documentation I prefer to use Doxygen. Purpose and goal: Heaps are very useful data structures and are used as building blocks in many algorithms. There are some heap data structures implemented in boost, for use in Boost.Graph for example, but at the moment they are coupled with the library they support. This project's goal is to decouple them into a boost/heaps library, cleaning them up where needed, and completely rewritting them if nescessary. All heaps will provide a common interface where possible, allowing algorithms writters to quickly change the data structure they are using without further changes to their code. The complexity of every operation on every heap will be documented, and tested to ensure correctness. A priority queue wrapper like std::priority_queue will also be provided. Heaps structures that will be provided: binary, binomial, fibonnaci, mutable heaps, suggestions are welcomed. Proposed Milestones and Schedule (work in progress): Binary heap implemented and submitted, possibly on top of STL heap algorithms, to have some foundation for the rest of the work, allowing tests on the other data structures to be compared to a simple but correct heap implementation. Moving heap structures from /boost/pending to the heap library, adapting them to a common interface and cleaning up where nescessary. No rewrites. Binomial Heap implementation. If any of the heap structures from pending were deemed unfit, rewritting them. This proposal is still under work, but I would like feedback from the community, not only on the project but also in the proposal itself.

3 2

GSoC 2010 - Boost.Phoenix
by Thomas Heller 22 Mar '10

22 Mar '10

Hi List, As the subject indicates I am interested in the Boost.Phoenix project for this years summer of code. At first, a little information on me. I am currently studying at University of Erlangen-Nuremberg in Germany. I am learning C++ since 2005. I have experience with Expression Templates. I used them as part of my bachelors thesis: http://www10.informatik.uni- erlangen.de/Publications/Theses/2009/Heller_BA09.pdf Some months ago I discovered the Boost.Proto library. I was trying to implement a DSEL for a GUI description language. This attempt can be found here: http://gitorious.org/phobos/main/trees/c014102b5aefb2592eef625047340fa92d85… However this approach was not continued, and I developed a spirit parser which gives more flexibility in that particular domain. I like the idea of Boost.Phoenix as it is right now. I think an implementation with Boost.Proto seems only natural. I searched the boost SVN repository but i couldn't find the prototypes you mentioned. A link to these would be helpful to be able further look into this project proposal. Regards, Thomas Heller

5 11

queries regarding the BigInt project @ GSoc 2010
by Ankit Malpani 22 Mar '10

22 Mar '10

hello all! i am really interested in developing the proposed BigInt library for Boost as a part of GSoC this summer . Here are a couple of queries i have. 1. With regard to the data structure for handling such integers - are we looking at bit-level implementation(less space and probably more execution time) or digit level manipulation (more space - and probably less execution time). i.e. for an n-digit number is it ok to use up [n/2 to n] bytes of space or necessary to stick to log n amount of space for a BigInt object. 1.1 The arbitrary precision calculations could be implemented using the BigInt data-structure along with a scaling factor variable 2. what all are the expected functions of this library - basic arithmetic(add, subtract ,multiply, divide, modulo, powers) , relational(<=, <, >,>=, !=, ==) , bitwise operation ,and maybe added functionality like gcd and lcm are some of the things i can think of, please do add on to the list . 3. i have no prior experience of using Boost libraries, will this prove to be a problem with regard to this project? Please do refine this design and point out all the flaws in my understanding. Hope to get your replies soon Thanking You, Cheers! Ankit Malpani, 3rd year Undergraduate | BE. (Hons) Computer Science, BITS Pilani - Goa Campus -- Ankit Malpani 3rd Year Undergraduate | BE. Hons Computer Science BITS Pilani Goa Campus

4 3

Trac XMLRPC support
by Vladimir Prus 21 Mar '10

21 Mar '10

Would it be possible to have XMLRPC plugin installed in Boost Trac instance? See: http://trac-hacks.org/wiki/XmlRpcPlugin The installation appears to be fairly simple (and indeed seems to just work somewhere else). This will allow to use third-party tools to grab tickets from Boost Trac, which will hopefully lead to more issues fixed :-) - Volodya

4 5

Boost.Graph and SoC2010
by Cezary Bartosiak 21 Mar '10

21 Mar '10

Hello, I am writing in regards to your SoC2010 participation. I am particurarly interested in developing the Boost Graph library. I have got a working knowledge of graph and networks theory and C++ programming experience. I think I can handle any of the ideas listed in Boost.Graph section of the Project Ideas page as well as I could provide my own proposals for the library. I would like to get in touch with somebody responsible for Boost.Graph in order to talk about possibilities and what are the priorities. I would be glad to provide this person with additional information. Best, Cezary

1 0

Re: [boost] [contract] Released Contract Programming Library on SourceForge
by Andrzej Krzemienski 21 Mar '10

21 Mar '10

> I have released on SourceForge a library that implements Contract > Programming (a.k.a. Design by Contract(TM) ) for C++. I am considering > to submit this library to Boost (as Boost.Contract). > Comments? Hi, Just another thought for a tiny extension that came to my mind. I tried to use the block invariant as a regular assert: int main() { CONTRACT_ASSERT_BLOCK_INVARIANT( fee fee fee ); } This code compiles and works fine. This is because "disabling block invariants" means that the entire macro invocation will disappear, inclusive of the nonsense I wrote inside. We are used to it because this is how C-style asserts work, but one of the advantage of asserts over comments, as it is often advertised, is that the predicates are checked for syntactic and (to some extent) semantic correctness. But this is not the case if we disable the assertion macros. I believe, it would be useful if "disabling block invariants" meant no run-time overhead, but still checking syntactic correctness. It would be possible if the macro CONTRACT_ASSERT_BLOCK_INVARIANT( expression ); were replaced with something like: ... sizeof( expression ) ... then, the expression is not evaluated, but required to be correct. If the value of sizeof is not used it should be eliminated by the compiler. Obviously, the same would be applicable for all the other types of checks, Regards, &rzej

2 2

GSOC 2010 : Boost.graph
by Chinmaya Poswalia 21 Mar '10

21 Mar '10

In boost.graph what would be better : a) Manipulate the original graph - it would save space(crucial for big graph) -if the user want he can copy the graph object to a new object and then feed into functions b) Generate a new graph - although space will be allocated but user has the opportunity to directly input the graph.

2 1

GSOC 2010
by Chinmaya Poswalia 21 Mar '10

21 Mar '10

Hello, I want to enquire following things? 1) Who are the mentors and can i get there email-address? I was not able to find there names on the project list site.

3 2

[Boost.Locale] More updates
by Artyom 21 Mar '10

21 Mar '10

Hello, Updates ------- I had uploaded updated version of Boost.Locale that includes few bug fixes and some cleanup of MSVC warnings so now it clearly compiles with /W3 under MSVC. Also some documentation updated. Docs: http://cppcms.sourceforge.net/boost_locale/html/ Tutorial: http://cppcms.sourceforge.net/boost_locale/html/tutorial.html Download (boost_locale-svn_r1112.zip): https://sourceforge.net/projects/cppcms/files/ Formal Review Request --------------------- I want to submit the library for formal review: - When can it be done? - Do I have to provide full BJam build before formal review (at this point it builds fine with CMake)? - Do you think that I should wait more, improve the library more and if so what exactly? Best, Artyom

3 3

[proto] call for help with msvc-7.1
by Eric Niebler 21 Mar '10

21 Mar '10

A recent check-in of mine (https://svn.boost.org/trac/boost/changeset/60706) broke proto on msvc-7.1. For instance, see <http://tinyurl.com/yg5wgw5>. I don't have access to this toolset anymore. Is there anybody out there willing to give this problem a shot? Or is it time to drop support for this old compiler? -- Eric Niebler BoostPro Computing http://www.boostpro.com

1 0

[Log] Pre-review questions
by Christian Holmquist 21 Mar '10

21 Mar '10

Hi, I'm currently attempting to convert parts of our production log system to using Boost.Log as part of my review. At first glance this looked like a trivial thing, since Boost.Log supports all features (and more!) than I would need to do this task. However, I can't find what I'm looking for in the docs and I wish to not poke around anymore in the Boost.Log code. Simple task 1 I've two source level attributes, System and Severity. I wish to create a log macro that takes these two arguments. enum System { SYSTEM_A, SYSTEM_B, }; enum SeverityLevel // I don't want to use the built-in severity enum, since need flexibility to add/remove levels. { FREQUENT, DEBUG, TEMP, INFO, WARNING, ERROR, }; void foo() { LOG(SYSTEM_A, INFO, "Hello cruel world" << "!"); } The above is not a complicated scenario and I should be able to quickly find an answer. Maybe I've just missed it..:) Simple task 2 Create a custom filter without using any Lambda magic. struct Filter { System sys; SeverityLevel sev; bool operator()(???) { // pseudo-code, since I don't know how to write this return Attributes["System"] == sys && Attributes["SeverityLevel"] >= sev; } }; Help appreciated, I would like to get to the more complicated parts.. / Christian

4 6

[gil] Can not open test.jpg
by Mariusz Kwiczala 20 Mar '10

20 Mar '10

Hi, I cannot open test.jpg from boost_1_42_0\libs\gil\example\test.jpg I use below application: InfranView FireFox IE Windows tools: (Paint, WLXPhotoGallery ... ) Does it mean that GIL uses some special, jpg file format? :) Best regards, Mariusz

3 3

Heaps and Queues for GSoC
by Thomas Mullaly 20 Mar '10

20 Mar '10

Hello my name is Thomas Mullaly and I am currently an undergraduate in Kent State's Computer Science department. I'm interested in submitting a proposal for this years Google Summer of Code for the Heaps and Queues project, but, first I was wondering if somebody could explain what the requirements are for this project. So I have a better understanding of the project when I write a proposal. -Thomas Mullaly

3 4

[SoC] Call for Mentors
by Andrew Sutton 20 Mar '10

20 Mar '10

All, Boost is once again participating in the Google Summer of Code program. I'm looking to establish an official list of possible mentors for student projects. I have a list of people that have already offered to mentor this year and people who I think might offer to mentor based on their past participation :) but I thought it would be a good idea to do this a little more officially. If you are interested in mentoring a student this year, please send your me your gmail id (e.g., andrew.n.sutton) and a short description of the kinds of projects you would be interested in mentoring. The gmail id is required for me to invite you to be a mentor, as far as I can tell. Please note that mentors should be prepared to work with one student throughout the course of the summer. This typically means reviewing the student's work on a weekly basis and providing guidance by answering questions and suggesting improvements on their work. Thanks, Andrew Sutton andrew.n.sutton(a)gmail.com

5 6

GSOC 2010
by Augustus Q Odena 19 Mar '10

19 Mar '10

Hi, My name is Augustus Odena. I'm really interested in a few of the project ideas that Boost has listed for Google Summer of Code (Heaps and Queues, Bits and Ints, Graph Connectives and Topology Generators). It was suggested to me by the Hints Page that I should join the mailing list - so I've done that. I'd really appreciate it if, whenever someone had the time, they could perhaps fill me in a little bit more on the details behind those projects and their relative merits. I'd be happy to provide any sort of information about myself that would be helpful. -- Thanks, Augie Odena

2 3

Range begin/end and Fusion begin/end
by Mathias Gaunard 19 Mar '10

19 Mar '10

In C++0x, begin and end are supposed to be found through ADL, and this might end up considering fusion::begin/fusion::end as possible overloads. Unfortunately, this breaks, as fusion::begin and fusion::end produce hard errors when passed something else than a fusion sequence. All in all, I find ADL very dangerous. Should it be advocated not to use the names "begin" and "end" for something else than ranges to avoid issues? I suppose that for Fusion, it could be possible to use SFINAE to mask the overloads if the arguments aren't fusion sequences.

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[log] Boost.Log formal review ongoing
by Vladimir Prus 19 Mar '10

19 Mar '10

Boosters, just a a friendly reminder that the formal review of the Boost.Log library, written by Andrey Semashev, is ongoing through March 17, 2010. There's still enough time to submit reviews and have them discussed, so please take a look at the library and share your thoughts. The documentation for the current version is available at: http://boost-log.sourceforge.net The downloads are at: http://sourceforge.net/projects/boost-log Here are the important points: 1. All comments are appreciated. Even if you don't have the time for in-depth study of everything, comments on parts of the library are welcome. In particular, if you are already using logging in your applications and have specialized requirements, you might want to directly check how the proposed library handles them. 2. The reviews and all comments should be submitted to the developers list, boost(a)lists.boost.org and the email should have "[log]" prefix in the subject to make sure it's not missed. The deadline for reviews is 23:59, March 17, PST = 2:59, March 18, EST = 7:59 March 18, GMT = 10:59, March 18 MSK 3. Please explicitly state in your review whether the library should be accepted. 4. The general review checklist is provided below: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Thanks, Volodya

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[SoC] Summer of Code
by Andrew Sutton 18 Mar '10

18 Mar '10

All, Boost is once again participating in the Google Summer of Code program. If you are a student who is interested in contributing to Boost, now would be a good time to discuss your plans on the *developer's* mailing list ( http://lists.boost.org/mailman/listinfo.cgi/boost) Student applications will be accepted here starting March 29, and can be submitted here: http://socghop.appspot.com/. If you have any questions, please feel free to ask me directly or respond to this message. Cheers, Andrew Sutton andrew.n.sutton(a)gmail.com

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[log] Boost.Log formal review
by M-Square 18 Mar '10

18 Mar '10

> Please explicitly state in your review whether the library should be accepted. Yes, I think the library should be accepted. In my view, the library should not be reviewed with the objective of whether it contains all possible implementations that might desired in the world, but whether it’s design and implementation is flexible enough to adopt useful extensions, like binary logging or a printf-style interface. It is unreal to expect from a first implementation to be the mother of all logging libraries, i.e. contain all desired functionality at once. It should be judged on whether it can BECOME the mother of all logging libraries and in my opinion it is flexible enough to do so. In our project, described in last month's ACCU Overload 95 (http://accu.org/index.php/journals/1606) we required a powerful logging/tracing library, mainly for the higher levels of the application. Since our guideline is to use Boost functionality wherever suitable, we particularly looked at the Boost library to fill our needs. It seemed to fulfil our requirements quite well, so we decided to take it on-board. We integrated it into our software, and first experience is that it works quite well. However, in the light of this review I would pay attention to a few aspects that I came across: - complexity of the interface, and how to improve - few design/implementation aspects - high-performance requirements INTERFACE COMPLEXITY ===================== A number of reviewers have mentioned the complexity of the interface and the fact that this might discourage new users. I think introduction of trivial logging partly reduced this problem, but whenever you want to use the library in a more subtle way, you have to know a lot and you have to do a lot. When implementing the various sinks and backend flavours I too found my code blurred with heavy template and shared-pointer handling at a level where I didn't want to see it. Thinking about how to improve this, it seemed to me that the library was lacking an extra interface level between trivial logging and the low-level interface of sinks etc. This extra interface should hide complexity, but still allow the user full control over the detailed aspects of the logging components. In my view this extra-level interface could be well-solved with a policy-based design. The user should just be required to provide the policies for the various aspects (front-end, back-end, formatter, filters) as well as the necessary parameters (file name etc.). The actual assembly of the logging components should be done by the library internally. I put this idea into practice, and, although not an expert in this field, developed a few policy-based creator classes, as well as the most common policies that I could forsee. This made the library much easier to manage and my code look much better. Adopting this approach would greatly remove the objections against the highly complicated interface. Users can just use the policies provided, and if the ones provided do not fit a user's needs, he can easily copy an existing one and modify it according to his wishes. The current design of the library allows insertion of this extra interface level well, proving its flexibility. DESIGN/IMPLEMENTATION ASPECTS =============================== When using the library I came across a few design aspects that might need some improvement. 1. Missing some polymorphism I know it is cursing in the church, but at certain moments I could do with a bit smarter use of polymorphism. To give an example, when my application shuts down unexpectedly, I want to tell the sinks around to stop their work and dump their contents if necessary. For the moment, and as far as i know, I still have to make a distinction between synchronous and asynchronous sinks, as only the asynchronous sinks support these stop methods, and even then I have to take the particular kind of backend in consideration in order to approach them, as this stop method is attached to the backend-templated class. It would be better to lift these methods to a class higher in the hierarchy. There are a few other points in the design were this is the case as well. This being said, there might be good reasons for the current design that I cannot oversee, but then I’d like to see them mentioned in the documentation. 2. In some cases, you might want to be more in control of what the logging library is actually doing. When sending off messages to a sync or async sink, you are only partially in control. Therefor my idea would be to provide something like a buffering logger, that buffers the messages it receives, and only sends it off to the core when the user tells him to. HIGH-PERFORMANCE REQUIREMENTS ================================ In my view, one of the most important aspects to judge a logging library on is its performance. I haven't seen to much about it in the reviews, but I think it is one of the first thing to look at when comparing libraries. I haven't performed comparison tests in detail, but from the results published it looks like Boost.Log is still lagging a bit behind in the multi-threaded case. The question is whether there is room for improvement here. If not, you will definitely loose out on faster libraries. When looking at our current project, there are certain parts of the application where we need a real fast (i.e. low cost) logging facility, and that is something that the current library is not going to offer (nor any of the more common logging libraries around; too often I read comments like "we choose rlog because it is twice as fast as.. "). So my idea would be to develop a lightweight logging module, that can operate next to the current functionality, but is particularly suited for applications or parts of applications where high performance is an issue. This could also be the light and simple library that people are asking for. I think it would be great to have both under one hood, allowing the user to select the kind of performance vs. capability that he wants. This also takes away the burden on the current implementation of having to be both lightweight and feature-rich. For the rest of the formal review questions: >What is your evaluation of the design? The design covers a good set of requirements to start with. It seems to be quite flexible to cater for new functionality. As stated, it might be useful to ease the use of the highly templated interface to prevent it of becoming a hurdle for novices. >What is your evaluation of the implementation? Only looked partly to the implementation, especially with performance in mind. I'm convinced that the implementation is good in general, although improvements can be made, especially with performance in mind. Date/time formatting is still a candidate in this case. >What is your evaluation of the documentation? The level of documentation is sufficient but not more then that. It seems to be written from the view of the developer or from a highly-experienced user. It therefor makes it difficult for a novice to use the library quickly. The introduction of trivial logging however improved this situation. In my view it should be reworked somewhat to cover the questions of less knowledgeable users (i.e. more explanation, more illustration through examples or references to the examples in the code). >What is your evaluation of the potential usefulness of this library? I think the library is very usefull. Regarding covered functionality it is somewhat equal to other well-known logging libraries, and the design is well-suited for extension in all areas where more functionality is required. >Did you try to use the library? With what compiler? Did you have any problems? We tried the library with Microsoft Visual C++ 8.0. We didn’t find any problems with the compiler, apart from some issue with MFC. There is a problem linking Boost.Thread statically with MFC, but this is a problem that resides outside Boost.Log. >Are you knowledgeable about the problem domain? Yes, developed this kind of functionality in earlier days. -- View this message in context: http://old.nabble.com/-log--Boost.Log-formal-review-tp27940788p27940788.html Sent from the Boost - Dev mailing list archive at Nabble.com.

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[log] Boost.Log Formal Review
by sam.gundry＠gmail.com 18 Mar '10

18 Mar '10

(This is my first Boost library review so take it easy...) > Please explicitly state in your review whether the library should be accepted. Yes. There are some concerns but I think it is very nearly complete, as far as my usage is concerned. These concerns are elicited in detail below but for now my three major ones are: - __LINE__, __FILE__ as attributes - Boost.DateTime formatting is sloooowwww - Ability to strip/compile out log messages in their entirety > What is your evaluation of the design? I haven't applied it heavily yet but so far the design seems logical. Separating the sinks and sources provides good flexibility. I'm yet to delve into usage of the filters though. > What is your evaluation of the implementation? I can't speak for the correctness of the implementation, but from a performance perspective, I've compared it to log4cxx (see the sourceforge thread Andrey has referred to) and it is comparable and/or better in most of my usages. Given the flexibility, I am prepared to pay for a little performance hits. A concern, which again Andrey has mentioned during this review, is the speed of Boost.DateTime formatting. From our comparisons, it is about 3-5x slower than log4cxx. Is it possible to have a bare-minimum date time formatter similar to log4cxx's implemented? I wrote a quick little wrapper using a customised strftime (for microseconds) with the most basic caching (which log4cxx's formatter uses) and performance was comparable. > What is your evaluation of the documentation? For most the part, very good. Definitely sufficient/adequate for acceptance. The design and installation pages, etc, are extremely clear and easy to read. Personally, I would prefer a few more concrete examples. For example, (a minor one, I know) but how do you specify keywords via a settings file. > What is your evaluation of the potential usefulness of the library? High. An efficient, highly functional and configurable logging library has much potential. I've found __LINE__ and __FILE__ missing as attributes. Andrey advised these are part of named_scope but the formatting is currently missing. Ideally - and I don't know if this is technically possible but - I would prefer these as just another attribute. Instead of requiring a BOOST_LOG_FUNCTION() call when you want to use them, you should be able to specify it as per usual, something a long the lines of: backend->set_formatter( fmt::format(%1% [%2%:%3%] %4%) % fmt::attr< SeverityLevel >("Severity") % fmt::attr< fmt::scope::file >("File") % fmt::attr< fmt::scope::line >("SrcLineNumber") % fmt::message() ); And then BOOST_LOG_SEV(...) << " a message" has the file and line attribute values already. Note, no need for BOOST_LOG_FUNCTION. With respect to compiling out the log messages: it would be desirable for security, code protection and/or performance if the ability to specify certain log records to be stripped out of the source code. A hack such as follows - which is obviously extremely inflexible - allows the users to define LOG_NTRACE to compile out all trace messages: # if defined (LOG_NTRACE) # define LOG_TRACE(logger, stream) (void(0)) ; # else # define LOG_TRACE(logger, stream) BOOST_LOG_SEV(logger, trace) << stream; # endif Something a lot smarter and flexible built into the library is desirable. Say, templated on your custom severity levels (or, indeed, any arbitrary attribute) and generating disable/enable macros. > Did you try to use the library? With what compiler? Did you have any problems? Yes. gcc 4.3.3, msvc 9, and qcc/gcc 4.x.x (can't remember) on QNX. No problems. > How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? Initially, at the end of last year, I compared performance and functionality to log4cxx. However, for this review, I have had a quick read of the docs (not the code) and attempted integrating it for our purposes, about 4 hours worth. > Are you knowledgeable about the problem domain? Not hugely. Middle-of-the-road. Neither here nor there. 5/10. Relatively average. A big thanks to Andrey for all his effort. Good luck with the acceptance! Cheers, Sam

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[log] Boost.Log formal review is over
by Vladimir Prus 18 Mar '10

18 Mar '10

Boosters, The forward review of the Boost.Log library is now officially over. Big thanks to Andrey for a solid proposal, and for everybody who participated in review. I plan to announce review results in a week from now, on Mar 25. Thanks, Volodya

1 0

[unordered] unordered_set::erase() complexity bug?
by Stefan Strasser 18 Mar '10

18 Mar '10

I think there is something very wrong with boost's implementation of unordered_set/map. 1 unordered_set<int> s; 2 for(int c=0;c<nr;++c) s.insert(c); 3 for(int c=nr-1;c>=0;--c) s.erase(s.find(c)); results: nr: time 20000: 0m0.244s 40000: 0m0.940s 60000: 0m5.584s 80000: 0m4.232s 100000: 0m34.814s 120000: 0m33.486s the function that's causing this is erase(), which is specified to be O(1) average, O(n) worst. I can't think of a reason why it should be O(n) in this case (perfect hash, erase doesn't rehash). but even if it was, the results should be at worst quadratic. load_factor() is below 1, bucket_count(x) is 1. if line 3 is changed to: 3 for(int c=0;c<nr;++c) s.erase(s.find(c)); 20000: 0m0.008s 40000: 0m0.016s 60000: 0m0.028s 80000: 0m0.032s 100000: 0m0.040s 120000: 0m0.044s as you would expect. even if I do the very same thing as above using Boost.Intrusive (using a load factor of 1), I get expected results: struct element : intrusive::unordered_set_base_hook<>{ ... for(int c=0;c<nr;++c) s.insert(*new element(c)); for(int c=nr-1;c>=0;--c) s.erase(s.find(element(c))); 20000 0m0.008s 40000 0m0.016s 60000 0m0.024s 80000 0m0.024s 100000 0m0.032s 120000 0m0.040s but surprisingly enough, the TR1 implementation shipped with libstdc++ also has a problem like that: 20000: 0m0.368s 40000: 0m1.448s 60000: 0m1.668s 80000: 0m7.160s 100000: 0m7.808s 120000: 0m13.349s am I missing something or is there really the same bug in 2 major implementations of unordered_set? it effectively caused a deadlock in some of my code. I'm using 1.38. no bug report in Trac.

20 48

[date_time] memory leak?
by Bartosz Marcinkiewicz 18 Mar '10

18 Mar '10

Hello, Code: #include <iostream> #include <boost/date_time/posix_time/posix_time.hpp> int main() { std::cout << boost::posix_time::microsec_clock::local_time() << std::endl; return 0; } Running through valgrind yields this: ==5963== ==5963== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 7 from 2) ==5963== malloc/free: in use at exit: 1,595 bytes in 27 blocks. ==5963== malloc/free: 63 allocs, 36 frees, 7,878 bytes allocated. ==5963== For counts of detected errors, rerun with: -v ==5963== searching for pointers to 27 not-freed blocks. ==5963== checked 173,784 bytes. ==5963== ==5963== 619 bytes in 20 blocks are possibly lost in loss record 7 of 7 ==5963== at 0x4A06FFC: operator new(unsigned long) (vg_replace_malloc.c:230) ==5963== by 0x352C0A0140: std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.12) ==5963== by 0x352C0A0D64: (within /usr/lib64/libstdc++.so.6.0.12) ==5963== by 0x352C0A0F01: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&) (in /usr/lib64/libstdc++.so.6.0.12) ==5963== by 0x408AD7: boost::date_time::date_generator_formatter<boost::gregorian::date, char, std::ostreambuf_iterator<char, std::char_traits<char> > >::date_generator_formatter() (in /home/bma/c++/boost_dt) ==5963== by 0x407B20: boost::date_time::time_facet<boost::posix_time::ptime, char, std::ostreambuf_iterator<char, std::char_traits<char> > >::time_facet(unsigned long) (in /home/bma/c++/boost_dt) ==5963== by 0x40494B: std::basic_ostream<char, std::char_traits<char> >& boost::posix_time::operator<< <char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, boost::posix_time::ptime const&) (in /home/bma/c++/boost_dt) ==5963== by 0x402AA0: main (in /home/bma/c++/boost_dt) ==5963== ==5963== LEAK SUMMARY: ==5963== definitely lost: 0 bytes in 0 blocks. ==5963== possibly lost: 619 bytes in 20 blocks. ==5963== still reachable: 976 bytes in 7 blocks. ==5963== suppressed: 0 bytes in 0 blocks. ==5963== Reachable blocks (those to which a pointer was found) are not shown. ==5963== To see them, rerun with: --leak-check=full --show-reachable=yes This is boost-1.37.0-9.fc11 (fedora core 11), gcc 4.4.1, x86-64 platform. Is it memory leak? Best regards, bma. -- Bartosz Marcinkiewicz tel. (+48) 516 034 243 e-mail: bma(a)epcon.pl, bartosz.marcinkiewicz(a)epcon.pl EPCON Sp. z o.o. www.epcon.pl adres: 53-407 Wrocław, ul. Gajowicka 114/116 tel. (+48) 71 361 75 55 ext.36 fax (+48) 71 361 74 44 NIP PL 899-24-92-498 KRS 0000190187 REGON 932963731 Kapitał zakładowy: 500 000 PLN

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Re: [boost] [unordered] unordered_set::erase() complexity bug?
by Christopher Crickmar 18 Mar '10

18 Mar '10

Given that the next iterator is meaningless for an unordered container and that cached_begin_bucket_ is always valid would it be bad manners to always return begin() ? Chris Crickmar

2 2

[multi_index] hashed_index erase(iterator) performance issue
by Brad Higgins 17 Mar '10

17 Mar '10

Hello, I have encountered a performance issue with multi_index's hashed_index erase(iterator) routine. The erase(iterator) call returns an iterator to the next element in the data structure. When using this routine in a sparsely populated, large sized hash, it takes a very long time to complete. For example, in my program, I have rehashed the hash table to 5 million buckets, and added 600,000 elements. Adding the elements takes a matter of seconds. Then, I delete the elements. Deleting the elements takes hours. I have profiled the code, and it looks to me like the performance hit is rooted in the increment of the iterator by the erase(iterator) call. Since the hash is sparsely populated, the increment must advance over many empty buckets for each erase(iterator) call, in order to advance to the next valid element. My question is, why does the erase(iterator) function return an iterator at all? (In comparison, sgi's stl::hash_map's erase() returns void.) The hash is unordered, so the returned iterator is a random value, which I think decreases its usefulness (I expect most clients will discard the returned iterator.) Additionally, the same behavior can be achieved by clients who desire this behavior if they post-increment their iterator argument themselves. That is: // After this line, cur_itr's initial element will be erased, // AND cur_itr will be updated to the next element in the hash table hash_table.erase(cur_itr++); Is there some way to remove elements from the hash without taking this iterator increment hit? Would it be possible to add an erase routine (of some other name) which accepts an iterator argument, but does not automatically increment the argument? Thanks, Brad

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[log] Comments
by Vladimir Prus 17 Mar '10

17 Mar '10

Hello, I have a few comments and questions about the Boost.Log library currently being reviewed. This email is not actually a review as such. It will help if I explain where I'm coming from. I am most familiar with two logging mechanism. One is from KDE libraries. There, you have severities and component ids -- which are just integers. So, source code might have kDebug(9012) << "doing something"; There's GUI to configure which components have logging enabled, and there's a way to omit explict component id. Another logging mechanism is from Eclipse. There, you specify severity and component id -- this time a string. In KDE, output goes to a console. In Eclipse -- to a log file. I would those mechanism to be sufficient for all my needs. Looking at the proposed libraries, I see two major issues: * There's no default setup that is comparable with the two mechanisms above. BOOST_LOG_TRIVIAL has only severity and it appears adding component information is complicated. In a sense, it looks like the library provides building blocks, but not a solution I can immediately use. * I think the library elegantly uses various facilities like Boost.Parameter and lambda expressions to provide an easy interface. Unfortunately, it seems like it's failing to provide any other interface for folks who might be unhappy with lambdas and named parameters. There's a more detailed explanation of those major issues: * It appears that out of the box, the proposed library does not address this component/severity style of logging that I've explained above. The proposed solutions at: http://permalink.gmane.org/gmane.comp.lib.boost.devel/200793 sound relatively complex. * The example of specifying filter without lambda functions given in http://permalink.gmane.org/gmane.comp.lib.boost.devel/200793 is frankly scary. I believe that in most languages and environments I worked with, lambda functions are just convenient alternative to defining the same function explicitly. Why is in Boost.Log, lambda expressions are blessed with extra convenience? * Why can't I use the library without named parameters? Surely, there are low-tech ways to specify things. * Why does channel_logger has a *single* parameter, and still requires that you pass it via named parameter. That is: src::channel_logger<> cl("foobar"); produces incomprehensible error message. Other concerns: * The library went too far with namespaces. Why are *six* nested namespaces necessary? This appears to be just asking for extra typing for no good reason. * Why is trivial logging printing the sequental number of each log message? I don't think this helps anything. Also, it prints the thread "number", on my system a hex string. I am not sure thread id should be part of trivial logging. Finally, I think by default, everybody things of logging as glorified std::cout, so trivial logging better print messages to console, not to a file. * Why does the library have light_rw_mutex? I would really prefer if everything thread-related be located inside Boost.Thread, so that at least the code can be readily audited. * It appears that the default behaviour of fmt::attr is to throw is the attribute with such name is not found. This seems like a bad choice to me. A logging library should never fail -- it is the last resort at diagnosing a problem in the field, and if it throws by default, it's useless. * I have used the attached script to measure code size impact. The script basically creates a test file with a single function calling BOOST_LOG_TRIVIAL and measures the size of that function depending on the number of calls. I've got 139 bytes per call for 'g++ -Os' and 174 per call for 'g++ -O3', which seems nice. This is function code only. When counting file size I get 324 and 514 respectively. For reference, kDebug gives 136 and 328 of file_size_bytes per call. I guess these results are OK. * I see lots of warnings in slim_string.cpp, e.g: ../../../../libs/log/src/slim_string.cpp:237: warning: control reaches end of non-void function I'd recommend working with maintainer of boost/throw_exception.hpp to add noreturn attributes on gcc, and silence the warning in other ways on other compilers. * Building the library with threading=single results in unresolved references to pthread functions. I belive that library should not use any sync mechanisms in this case. Thanks, Volodya

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[log] Formal review
by Alexander Arhipenko 17 Mar '10

17 Mar '10

Boost.Log library formal review. > Please explicitly state in your review whether the library should be accepted. Yes, library should be accepted. Some explanation here. What means 'boost library' to me? It's very reliable, portable, efficient, sexy (in sense of code style) component that could satisfy from 90 to 95 % of regular user cases. Even if someone has an issue with such component - this issue could be resolved quickly (up to 1 hour). This quickness usually explained by clean library design and also by rich community support (the last sentence I've made based on my own experience with boost). IMHO, Boost.Log nicely fits into all the written above. Andrey spent many months (I've put an eye on Boost.Log in August 2008) polishing library's design, implementation, improving documentation. It would be nice to see the result of such huge efforts in Boost distribution. - What is your evaluation of the design? The overall design seems to be very orthogonal and does not mix different things together. - What is your evaluation of the implementation? I didn't dig deeply (except some functionality related to log rotation). At first glance, it's high quality, modern c++ code. It doesn't take too much time to understand it and make modifications. - What is your evaluation of the documentation? The first thing I except from any documentation - it's a "quick jumps" scenarios, i.e. workable small code snippets that compiles, works and give the user brief explanation on how to perform usual tasks using the library. I've found it in the latest docs and that was nice. Tutorial section is organized in 'from simple to complex things' form. This is very nice. Overall quality of the documentation is fine to me. - What is your evaluation of the potential usefulness of the library? Every application could really benefit from using logging. Especially server ones, that are running 24/7 without frequent human interaction. But I'm saying banal things now. In short, potential usefulness of such library is very high. - Did you try to use the library? With what compiler? Did you have any problems? Yes, I've tried it. gcc 4.1.2 (RHEL 5 x86_64, RHEL 5 i686). msvc 9 (Windows i686). The only problem I had it was warnings on gcc. But that was RC3 of the library, I guess Andrey addressed those issues in the latest version. - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? We've integrated Boost.Log RC3 into our server application (in the end of January 2008). Now it's running in several production environments. I've spent several days writing tiny wrapper for Boost.Log. This wrapper was required due to reasons above: 1) I was not sure about the future: whether we would like to switch to the different logging library etc., nowadays answer to this question is categorical NO 2) All the components of application should have common logging formatting, logging levels, also some 'shortcuts' were needed (such as namespace aliases etc) Also, we did some Boost.Log profiling with valgrind (memcheck tool). As far as I remember, none issues were found. - Are you knowledgeable about the problem domain? Knowledgeable from the end-user point of view. I know, what I want to have from logging (e.g., various severities, filtering, log files rotation, thread-safety). - Questions I have one question in regards to log rotation. (I guess, I was asking it last year when RC3 was presented). Is it possible to setup log rotation in a following way: file.log - earlies log file (today) file1.log - older log file (yesterday) file2.log - oldest log file (the day before yesterday). This way Apache, Samba etc. performs rotation. Also, this rotation behavior is default in Python logging module. Also, this behavior is default in my wolrd ;). Many thanks to Andrey for Boost.Log contribution. Many thanks to Volodya for being a review manager. Regards

2 1

[log] How to set/reset a channel-specific filter
by Andreas Huber 17 Mar '10

17 Mar '10

Hi We're currently reviewing Boost.Log and are wondering what is the best way to implement channel-specific filters. More precisiely, we are currently using the following "objects": - 2 sinks (one to debug output window, one to file) - several severity_channel_logger_mt objects, all declared with BOOST_LOG_DECLARE_GLOBAL_LOGGER, each of these is guaranteed to have a unique channel name For each of the channels, we would like to set a filter that only applies to records logged through the given channel. Since we can't seem to set a filter on the logger itself, we're wondering what is the best way to accomplish this? It seems as though both the core as well as the sinks only accept one filter. So, it seems we would have to a) assemble a filter expression that includes all the channels we'd like to filter on. *Or*, we could b) add exactly two sinks per logger object and set the desired filter on both sinks. Of course, we'd still want to only log to one file, so the question arises whether it is safe to have multiple sinks write to one file. If we go with method a), we'd need a way to enumerate all global loggers. If we go with b), we'd need a method to enumerate all the sinks in the system. We have not found a way to accomplish any of these tasks, how do we do this? Thanks & Regards, -- Andreas Huber When replying by private email, please remove the words spam and trap from the address shown in the header.

2 7

[python]missing file
by K. Noel Belcourt 17 Mar '10

17 Mar '10

Hi, Trunk tests are dying with this error. error: Unable to find file or target named error: 'builtin_converters_ext' error: referred from project at error: '../libs/python/test' -- Noel

1 0

[exception] Unreachable returns (was [log] Comments)
by Daniel James 17 Mar '10

17 Mar '10

On 15 March 2010 10:45, Vladimir Prus <ghost(a)cs.msu.su> wrote: > > * I see lots of warnings in slim_string.cpp, e.g: > > ../../../../libs/log/src/slim_string.cpp:237: warning: control reaches end of non-void function > > I'd recommend working with maintainer of boost/throw_exception.hpp to add noreturn attributes on > gcc, and silence the warning in other ways on other compilers. I think Boost.Exception already does that (http://www.boost.org/boost/exception/detail/attribute_noreturn.hpp) but this is something I've been meaning to ask about, as I had to deal with it for iostreams. Our normal solution is to use BOOST_UNREACHABLE_RETURN (http://tinyurl.com/yjjdzsh) but that doesn't work for compilers that don't understand a 'noreturn' attribute. I hacked together my own version (http://www.boost.org/boost/iostreams/detail/config/unreachable_return.hpp) but it's only a short term solution and could break if throw_exception changes. It would be nice to have a proper solution in Boost.Exception, or maybe there already is one and I missed it? Daniel

2 2

[statechart] Undefined type
by s_a_white＠email.com 16 Mar '10

16 Mar '10

Hi, I've inherited some code that currently compiles and runs under Linux (gcc 4.2.1) and am looking to switch to Windows using the vs 2003 with SP1. Unfortunately the code fails to compile with undefined symbols. An example of the code is as follows: #include <boost/statechart/event.hpp> #include <boost/statechart/state_machine.hpp> #include <boost/statechart/simple_state.hpp> #include <boost/statechart/transition.hpp> #include <iostream> namespace sc = boost::statechart; struct EvStartStop : sc::event< EvStartStop > {}; struct EvReset : sc::event< EvReset > {}; struct Active; struct Stopped; struct Running; struct StopWatch : sc::state_machine< StopWatch, Active > {}; struct Active : sc::simple_state< Active, StopWatch, Stopped > { typedef sc::transition< EvReset, Active > reactions; }; struct Stopped : sc::simple_state< Stopped, Active > { typedef sc::transition< EvStartStop, Running > reactions; }; int main() { return 0; } I'm aware that the code is incomplete as Running is only forward declared. It is provided this way since the real model under Linux is broken up across multiple headers rather than all being in one header. Under Linux the above code compiles without an issue but vs 2003 complains about Running being undefined. Removing sc::transition< EvStartStop, Running > makes the compilation problem disappear. A similiar issue exists for Windows if Running was defined but uses an inner state that was only foward declared. Again Linux seems to have no problems. For vs 2003 wrapping the reactions or inner state with mpl::list<> does not fix the problem. Can anyone suggest if what is being done here is broken under vs 2003, or should not be allowed under gcc? Are there workarounds for the boost headers for vs 2003 or recommendations to allow splitting the state machine across multiple headers? Best Regards, Simon

2 8

[sandbox] need Apache/.htaccess/rsync help
by Eric Niebler 16 Mar '10

16 Mar '10

A bit off-topic, but I don't know who the maintainer of the boost-sandbox project on sourceforge.net is. I use this project to post updated documentation for my boost libraries. (For instance, see <http://boost-sandbox.sourceforge.net/libs/xpressive>.) Today, I tried to update Proto's docs using a script I wrote for this purpose eons ago: #!/bin/sh rsync --delete --rsh=ssh --recursive html/* eric_niebler,boost-sandbox@web.sourceforge.net:/home/groups/b/bo/boost-sandbox/htdocs/libs/proto/doc/html For ages, this has Just Worked, but for some reason, it has recently stopped working. I thought I'd check here before requesting support from SF.net. The behavior I'm now seeing is that I get 403 error for any page in Proto's docs. See: http://boost-sandbox.sourceforge.net/libs/proto/doc/html/index.html The error says: "3. Error notes: Server unable to read htaccess file, denying access to be safe" Wha'? Any help? FYI, here's sf.net's docs on rsync over ssh. From what I can tell, I'm doing everything right: http://sourceforge.net/apps/trac/sourceforge/wiki/Rsync%20over%20SSH#Projec… -- Eric Niebler BoostPro Computing http://www.boostpro.com

2 4

Re: [boost] suggestion on assertion macros
by DE 16 Mar '10

16 Mar '10

hi all on 14.03.2010 at 18:15 Roland Bock wrote : > Hmm. I use gcc (4.2.4) and I get the warning (-Wall -Wextra). That's why > I proposed that code in the other part of this discussion (with great > help from Peter and Steven): > #include <cassert> > #ifdef NDEBUG > #ifdef assert > #undef assert > #define assert(cond) static_cast<void>(sizeof(cond? 0: 0)); > #endif > #endif > int main() { > int i = 0; > assert(i); > } > This way, I get no warning about variable i being unused, it is even > being made sure that the condition for the assertion is verifiable and > still the code results in nothing if NDEBUG is defined. > I plan on using that myself. I think it would be useful for others, too. i came to the same thing this solution works perfect with msvc80 and i feel like going to adopt it for my personal use but i think you missed the order of macro directives if i get it right it should be #ifdef NDEBUG #ifdef assert #undef assert #endif //swapped this and the following lines #define assert(cond) static_cast<void>(sizeof(cond? 0: 0)); #endif and i agree that defining an "advanced" project-specific macro is really a better solution than redefinition of 'assert()' on improving assertions: my only concern was to propose a solution to the warning issue while NDEBUG is defined (and similar situations) i picked 'assert()' only for illustration purposes of course any other assert-like system may (or may not?? i believe it does) be improved in this specific sense my opinion is that specific assertions (like contract statements mentioned) are defined the way the author prefer, i.e. there is no typical restrictions on that so the discussion on "improving assertions" or "contract programming implementation" is not my concern for now and i leave it up to you guys -- Pavel

5 11

invalid null pointer error in serialization with MSVC2008
by h yh 16 Mar '10

16 Mar '10

Hi, I am getting a very strange runtime error using boost serialization library with MSVC2008. I called the following template in my program. template <class T> void loadData(std::string fileName, T &t) { std::ifstream ifs(fileName.c_str()); boost::archive::text_iarchive ia(ifs); t.clear(); ia >> t; ifs.close(); } it gets an assertion failed when running into boost::archive::text_iarchive ia(ifs); Debug Assertion failed: invalid null pointer Here is the stack frame: msvcr90d.dll!memcpy_s(void * dst=0x00000000, unsigned int sizeInBytes=4294967295, const void * src=0x07953f63, unsigned int count=22) Line 55 + 0x2f bytes msvcp90d.dll!std::char_traits<char>::_Copy_s(char * _First1=0x00000000, unsigned int _Size_in_bytes=4294967295, const char * _First2=0x07953f63, unsigned int _Count=22) Line 582 + 0x16 bytes msvcp90d.dll!std::_Traits_helper::copy_s<std::char_traits<char> >(char * _First1=0x00000000, unsigned int _Size=4294967295, const char * _First2=0x07953f63, unsigned int _Count=22, std::_Secure_char_traits_tag __formal={...}) Line 714 + 0x15 bytes msvcp90d.dll!std::_Traits_helper::copy_s<std::char_traits<char> >(char * _First1=0x00000000, unsigned int _Size=4294967295, const char * _First2=0x07953f63, unsigned int _Count=22) Line 706 + 0x22 bytes msvcp90d.dll!std::basic_streambuf<char,std::char_traits<char> >::_Xsgetn_s(char * _Ptr=0x00000000, unsigned int _Ptr_size=4294967295, int _Count=22) Line 342 + 0x1a bytes msvcp90d.dll!std::basic_streambuf<unsigned short,std::char_traits<unsigned short> >::_Sgetn_s(unsigned short * _Ptr=0x00000000, unsigned int _Ptr_size=4294967295, int _Count=22) Line 118 msvcp90d.dll!std::basic_istream<char,std::char_traits<char> >::_Read_s(char * _Str=0x00000000, unsigned int _Str_size=4294967295, int _Count=22) Line 698 + 0x27 bytes msvcp90d.dll!std::basic_istream<char,std::char_traits<char> >::read(char * _Str=0x00000000, int _Count=22) Line 712 MyProject.exe!boost::archive::text_iarchive_impl<boost::archive::text_iarchive>::load() + 0xad bytes MyProject.exe!loadData<std::set<GamingNote,GamingNote,std::allocator<GamingNote> > >(std::basic_string<char,std::char_traits<char>,std::allocator<char> > fileName="nocturne.gnt", std::set<GamingNote,GamingNote,std::allocator<GamingNote> > & t=[0]()) Line 14 + 0x14 bytes It happens when the text_iarchive class constructs, so I am sure it's nothing to do with the serialize function of T, but something between boost and std::ifstream. The wierd thing is I didn't come across this program at the first time. It appears suddenly during development. If I separate the serialization code to a single cpp file, it doesn't have any problem at all. By the way, I am intergrating Qt and Ogre with boost by the way, but that seems not to be quite helpful to identify this problem. Any ideas about that? Yuheng Huang

1 0

boost::log review (printf style api)
by Tom Brinkman 16 Mar '10

16 Mar '10

>> It is actually more relevant than a "flame war." We are discussing how a log API should look to be most useful >> (in terms of depth and width), and that discussion pertains to all (new) libraries of Boost: do we want them >> to be used by the larger C populace? How much are we ready to sacrifice in expressivity (or succinctness) in >> order to widen our target? Should we have C wrappers for the most "utilitarian" libraries, such as a log library? >> My point is that Boost is a C++ library and should not care at all about the impact on C developers, or people >> who happen to be used to that "glue language," even for their C++ development. I still think it is a valid >> discussion to have. Well said. Good summary, although as noted, I disagree with your conclusion. The larger question is -- what has gone wrong with boost? Why do so many libraries languish in the review queue. Why has the the C++ standard taken so long to get enough momentum to pass through committee. In my view, C++ is tired. Boost is an experiment of a particular style of development, that being functional, generic, orthogonal and "non-hieararchical". Boost through its heavily template ladden libraries offered this style of development, and it had great appeal to those who had grown tired of object oriented style of development. The experience of those of us that have developed with this style over the years has been mixed. Like anything, somethings are nice, somethings are more trouble than there worth. Fortunately, for those of us that have an appreciation for functional programming will still be highly relevent in the future. The reason has primarily has to do with parralel programming which lends its self very nicely to functional programming, which is what boost is all about. The way I explain it, functional programming is just a variation of procedural programming with a different way of passing around state. Unfortunately, this advanced programming style is often abused in hideous ways. Particularly, when they are used in small utilty libraries which should be simple and general purpose, and not push a particular style of development. I've already made this point, but I'll make it again. Utility libraries should be agnositic and usable across the widest variety of programming styles, that being procedural, objected orienteated or functional. This boost::log library should not be approved without a simple "C" friendly api. That being a printf style api. Failure to include a "printf" style api will only continue to marginalize boost further to small subset of c++ developers. Most develpers will look at the api without a printf and go, HUH?

7 10

Collection of Jamfiles for 3rd-parties?
by Mateusz Loskot 15 Mar '10

15 Mar '10

Hi, I'm wondering if would it make sense to have a directory in Sandbox or close where Jamfiles for various third-party programs and libraries could be maintained. I imagine it could make it easier to integrate various dependencies with Boost and Boost Sandbox libraries. For example, GIL makes use of libpng, libjpeg, libtiff, libz, gzip/bzip2 are used by others too. I found that HAIKU OS maintains collection of Boost Build enabled libraries: http://dev.haiku-os.org/browser/haiku/trunk/src/libs I'm not suggesting to do the same, but perhaps it would make sense to maintain Jamfiles only, so users can download them and refer to such libraries using symbolic targets. I'm curious of your comments? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org

2 1

base class for boost::array
by Peter Myerscough-Jackopson 15 Mar '10

15 Mar '10

Dear all, In using boost::array I have felt the need to pass around boost::array's of an unknown size (unknown to the function receiving the array). I have therefore created an abstract base class for boost::array so that I can create a pointer to a common base class for arrays of different sizes. Essentially std::vector's of different sizes can be passed into a function with a fixed prototype, but because boost::array constructs a different type for each array size, a single fixed prototype cannot be described such that it can be called with different sizes of boost::array. In code I can write (toy functions) : double sumTotal(const std::vector<double>* values) { double result = 0 ; BOOST_FOREACH(double v, values) { result += v; } return result; } But I can't write: double sumTotal(const boost::array<double>* values) { double result = 0 ; BOOST_FOREACH(double v, values) { result += v; } return result; } Without the second function being a template function, i.e. I cannot provide a library that takes a boost::array<double>. With the attached base class, I could define a function that takes a boost::array_base<double>. Since, I think, the ability to allow boost::array to be used in this way is that it requires the use of virtual functions, I have written it so that the inheritance is optional. It is enabled with a #define before including array.hpp . Is this useful? (I am aware that I maybe could use a boost::range) Thanks for your time, Peter Ps. On my current compiler, swap and operator= could not be uncommented in the array_base class. PPs. This is my first post to boost dev, please be kind... J Dr Peter Myerscough-Jackopson - Senior Engineer Tel: +44 (0)23 8076 7808 Fax: +44 (0)23 8076 0602 Web: http://www.macltd.com/ <BLOCKED::http://www.macltd.com/> Email: peter.myerscough-jackopson(a)macltd.com <mailto:peter.myerscough-jackopson@macltd.com> MULTIPLE ACCESS COMMUNICATIONS LIMITED is a company registered in England at Delta House, The University of Southampton Science Park, Southampton, SO16 7NS, United Kingdom with Company Number 1979185 and VAT Number GB 411942866

5 4

[Boost.Locale] New Release
by Artyom 15 Mar '10

15 Mar '10

Hello Boost List! ================= I'm glad to introduce updated version of Boost.Locale library: This library was designed for Boost and created because of needs CppCMS framework. I'm looking forward to formal review and general inputs from Boost.Community. Documentation: http://cppcms.sourceforge.net/boost_locale/html/index.html Download: From: https://sourceforge.net/projects/cppcms/files/ File: https://sourceforge.net/projects/cppcms/files/boost_locale/boost_locale.zip… Boost.Locale is a library that brings high quality localization facilities in C++ way. It provides the natural glue between C++ locales framework, iostreams and powerful ICU library giving: * Correct case conversion, case folding and normalization * Collation including support of 4 Unicode collation levels. * Date, time, timezone and calendar manipulations, formatting and parsing including transparent support of calendars other then Gregorian. * Boundary analysis for characters, words, sentences and line-breaks. * Number formatting, spelling and parsing. * Monetary formatting and parsing. * Powerful message formatting including support plural forms, using GNU catalogs. * Character set conversion. * Transparent support of 8-bit character sets like Latin1. * Support of char, wchar_t and C++0x char16_t, char32_t strings and streams. New in this version: ==================== a. Fully redesigned break iterator interface b. Added date_time and calendar support that allow manipulating with dates over non-Gregorian calendars c. Implemented full set of unit-tests d. Added support of many platforms and compilers. e. Lots of bug fixes. f. Complete reference with Doxygen g. Many tutorial updates, thanks to Markus Raab inputs Tested compilers and platforms: =============================== - Compilers: - GCC 3.4, 4.1, 4.2, 4.3, 4.4 - Intel Compiler 11.0 - SunStudio 12 with STLPort - MSVC 2008 - Operating Systems: - Linux - FreeBSD - OpenSolaris - Windows XP - Windowns XP/Cygwin - ICU Versions: 3.6, 3.8, 4.2 Full list of tests: =================== - Linux: - Debian GNU/Linux 2.6.18, x86, GCC 4.1.2, ICU 3.6.1 - Debian GNU/Linux 2.6.26, x86_64, GCC 4.3.2, ICU 3.8.1 - Debian GNU/Linux 2.6.26, x86_64, GCC 4.4 -std=c++0x, ICU 3.8.1 (Some faults on char16_t/char32_t support) - Debian GNU/Linux 2.6.26, x86_64, Intel Compiler 11.0, ICU 3.8.1 - FreeBSD - FreeBSD 8.0, i386, GCC 4.2.1, ICU 3.8.1 - OpenSolaris: - SunOS OpenSolaris 5.11, i386; Sun Studio 12, with STLPort, ICU 4.2 - SunOS OpenSolaris 5.11, i386; GCC 3.4.3, ICU 4.2 - Windows XP/SP2 - Cygwin 1.5, GCC 3.4, ICU 3.8 - Cygwin 1.5, GCC 4.3, ICU 4.2 - Windows XP/SP2, Mingw/GCC 4.4, ICU 4.2 (Static build only) - Windows XP/SP2, MSVC9 (2008)

10 19

[iterator] Help needed understanding output_iterator requirements
by Thomas Klimpel 15 Mar '10

15 Mar '10

Dear iterator experts, Jesse Perla recently reported that boost::multi_array fails compilation for many basic tasks on MSVC 2010. I investigated the failures, because I had already investigated other failures on MSVC 2010 reported by Jesse Perla for boost::ublas. While I'm quite familiar with boost::ublas, I'm a complete novice with respect to boost::multi_array and boost::iterator. I could track the failures to a specific (intentional?) behavior of iterator_facade from Boost.Iterator (more specifically of facade_iterator_category.hpp): http://lists.boost.org/Archives/boost/2010/03/163039.php Thomas Klimpel wrote: > What effectively happens it that the iterator gets the category > "input_iterator", but std::copy wants to have an "output_iterator". I > think I understand why the iterator doesn't satisfies the requirement > of a "forward_iterator", but it's unclear to me why it didn't qualify > as an "output_iterator". There is an "input_output_iterator_tag" in > "boost/iterator/detail/facade_iterator_category.hpp", so it would have > been possible for the iterator to be both "input_iterator" and > "output_iterator". However, it seems to me that > "input_output_iterator_tag" is never used in the Boost.Iterator > library. I would have to read more about "output_iterator" to > understand whether Boost.Iterator is correct here. With my current > understanding of "output_iterator", I would say it's a bug in > "boost/iterator/detail/facade_iterator_category.hpp". > > Perhaps somebody with more knowledge about "output_iterator" and > Boost.Iterator can explain to me why an iterator using the > "boost::random_access_traversal_tag" for the "CategoryOrTraversal" > template parameter of "iterator_facade" will never get the category > "output_iterator" (or "input_output_iterator_tag"). Of course I could go on and read more about "output_iterator", or find out whether the Boost.Iterator documentation has to say something about this issue, but since I only came to this problem because I wanted to help Jesse Perla on a problem with boost::multi_array, I would much prefer if an "iterator expert" could "take over". Regards, Thomas

2 2

[log] Boost.Log formal review
by Vladimir Prus 15 Mar '10

15 Mar '10

Boosters, the formal review of the Boost.Log library, written by Andrey Semashev, starts now and will run through March 17, 2010. The documentation for the current version is available at: http://boost-log.sourceforge.net The downloads are at: http://sourceforge.net/projects/boost-log Here are the important points: 1. All comments are appreciated. Even if you don't have the time for in-depth study of everything, comments on parts of the library are welcome. In particular, if you are already using logging in your applications and have specialized requirements, you might want to directly check how the proposed library handles them. 2. The reviews and all comments should be submitted to the developers list, boost(a)lists.boost.org and the email should have "[log]" prefix in the subject to make sure it's not missed. The deadline for reviews is 23:59, March 17, PST = 2:59, March 18, EST = 7:59 March 18, GMT = 10:59, March 18 MSK 3. Please explicitly state in your review whether the library should be accepted. 4. The general review checklist is provided below: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Thanks, Volodya

16 52

Fwd: Re: [log] review part 1
by Andrey Semashev 15 Mar '10

15 Mar '10

Due to technical reasons this reply went off-list. For sake of keeping the conversation public, I'm reposting it. -------- Original Message -------- Subject: Re: [boost] [log] review part 1 Date: Sat, 13 Mar 2010 16:08:14 +0300 From: Andrey Semashev <andrey.semashev(a)gmail.com> To: Steven Watanabe <watanabesj(a)gmail.com> On 03/12/2010 07:22 AM, Steven Watanabe wrote: > I mostly have documentation notes at this point. Andrey, since I have so > many, and they're mostly fairly minor, would it be better if I made > a patch for the documentation source? Yes, that would be great. I quickly reviewed your suggestions, and they all look reasonable (I always have a hard time with articles). Thanks! > I think newbies should probably be replace globally with new users, > since I kind of feel that the term newbie is somewhat derogatory. Ok. I didn't mean to offend anyone, of course. :) > http://boost-log.sourceforge.net/libs/log/doc/html/log/defs.html > ================================================================================ > > For Log record: > I don't like the expression "A single pack of information," although > I can't think of anything better off hand. A collection of data,...? > ================================================================================ > > Issues: > > Instead of compiling a narrow or wide library, why don't you use > libboost_log > and libboost_wlog? There are parts that would be the same in both these libraries. Most notably, singletons of file_collector repository and some constants. This might lead to linking problems if someone tries to use both versions of the library. > I agree with other comments that I saw about Attribute being > a poor choice for what it does. I would prefer that the term "Attribute" > should be used for what you call an "Attribute Value," and that > there should be a different term, like "Attribute Extractor" for > what you call an "Attribute." My understanding of the term "attribute" is that it's some kind of meta-information that defines the concrete values that will be attached to log records. I'm ready to agree that the word "attribute" doesn't bring my intention precisely, but the alternatives don't quite get closer. "Extractors" are reserved for another tool in the library.

5 6

static in_class constants
by Christian Henning 15 Mar '10

15 Mar '10

Hi there, I'm finishing up some linker problems I have with gcc. One area of problems seems to be static in_class constants that I have declared in my header file. MSVC doesn't have problem with it but gcc is complaining. I'm wondering how other libs in boost are dealing with these problems. For instance in my new gil::io lib I define some tags in pnm_tags.hpp as follows: /// Defines type for image type property. struct pnm_image_type : property_base< uint32_t > { BOOST_STATIC_CONSTANT( type, _mono_asc = 1 ); // Monochrome ASCII encoding BOOST_STATIC_CONSTANT( type, _gray_asc = 2 ); // Gray level ASCII encoding BOOST_STATIC_CONSTANT( type, _color_asc = 3 ); // sRGB color ASCII encoding BOOST_STATIC_CONSTANT( type, _mono_bin = 4 ); // Monochrome binary encoding BOOST_STATIC_CONSTANT( type, _gray_bin = 5 ); // Gray level binary encoding BOOST_STATIC_CONSTANT( type, _color_bin = 6 ); // sRGB color binary encoding }; Thanks, Christian

7 27

Review - boost::log
by Tom Brinkman 15 Mar '10

15 Mar '10

Should boost log be accepted into the boost library? My vote is no. This library will just reinforce boost's reputation as being a repository of needlessly complicated highly templatized libraries for relatively easy programming tasks. I don't mind this added complexity when it comes to genuinely difficult problem spaces. In my view, however, logging is not one of those problem spaces. Logging is one of those things that if it takes longer than 10 minutes to read the documentation and get up to speed, it will not get used. What is your evaluation of the design? Very much in the spirit of a typical boost library. However, it has very little attention to "C" interfaces and makes heavy use of templates. I suppose because this is boost, that that is acceptable. However, boost and the c++ community at large should start moving towards a more friendly attitude towards a "C" style api for utility libraries. Most non-boost c++ developers will dismiss this library out of hand, not because its a bad library, its not, it's just more of the same. Heavy handed use of templates. I guess I've spent too much time over the last 5 years ripping out poorly conceived heavily templated code. The thought of adding to this madness, with another utility library that is burdened by templates is hard to swallow. What is your evaluation of the documentation? Good What is your evaluation of the potential usefulness of the library? Logging is useful. Yes. Did you try to use the library? With what compiler? Did you have any problems? Yes. GCC++. No problems How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? 2 hours Are you knowledgeable about the problem domain? Yes. I was the review wizard for three years and have followed the progression of boost from the beginning, Tom Brinkman

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Re: [boost] suggestion on assertion macros
by Andrzej Krzemienski 15 Mar '10

15 Mar '10

> there were a discussion recentrly about verifying arguments of > assertion macros while checks are turned off > i've got an idea of how to check the argument(s) and guarantee zero > code size and runtime overhead Hi, This is a good addition to assertions, but once we decide that we are improving assertions, there is much more that needs an improvement. Most of them are listed in the thread on Contract++ library (proposed for Boost) that you are already referring to. But let me list the potential improvements here. 1. If the expression in assertion throws an exxception, this should also be considered an assertion failure. Otherwise evaluating or not evaluating an assertion may render different program behavior. You can implement that by wrapping the expression with a try-catch block; but then assertion is a statement rather than an expression. Personally I think it is even better that an assert in a statement and it cannot be a subexpression of a bigger expression, but it no longer complies to assertion interface. Lambdas have the capability of changing statements into expressions, but we do not have them yet. 2. Be able to disable some assertions, but not all, e.g. I want the following assert in my code never to execute: assert<low_level>( is_sorted( v.begin(), v.end() ) ); find_logarithmic( v.begin(), v.end(), val ); Simply because it may be too slow even in debug. 3. I may want to disable even syntax checking in order for my compilation to run faster. I guess we should also consider user that prefer slower applications that compile faster 4. Make sure that the expression does not access any global variables. Well, we shouldn't really forbid that but give it as an option for the programmers that like "functional style" programming. I don't know how to do that now, but with lambdas, I believe it is posible with empty capture lists. 5. At least try to limit the possibility of the expression having any side effect. Contract++ ttries to do it by enforcing the const correctness of some inputs. Perhaps, even the old assert is left alone and some super-assert like the one from Concept++ should be incorporated into Boost and be the preferred way of veryfing user assumptions. Regards, &rzej

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[iostreams] Add char_traits to the Device concept
by thomas weidner 14 Mar '10

14 Mar '10

Hi, i came across this issue when trying to use iostreams with a custom character class and custom character traits. The main problem is, that iostreams assumes std::streampos as the position type for all devices. Some parts of iostreams, like detail::indirect_streambuf honor the char traits' custom pos_type, but this will cause build failures as the underlying device (even code_converter) uses std::streampos as position type. My proposal is to add an associated character traits type to a Device. A Device type whould therefore not only provide information about the underlying character type, but also about the used pos_type, off_type and code conversion (not) done. I would even use traits different from std::char_traits<Ch>/iostreams::char_traits<Ch> as default character traits for most devices. Most devices like for example file_descriptor_sink don't do any code conversion, so a pos_type which contains a mbstate_t is useless and leaves the user with the impression, that code conversion *is* done. A simple integral type like C's off_t should do fine. Let's call those traits binary_char_traits for now. As an implication of this a iostreams::stream_buffer<file_descriptor_sink> should use the Device's char traits type, so should be a std::basic_streambuf<char, binary_char_traits<char> >. Especially it whould not be useable with std::iostream. This is IMO a nice and very clean result, as an iostream expects characters on which code conversion has been performed. You whould need to plug a code_converter in between. Some thoughts about iostreams::code_converter. Perhaps we should change the Codecvt template parameter to a second traits type. This traits type will become the code_converter's associated char traits type. the codecvt type could be an extra template parameter or is simply std::codecvt<code_converter_char_type, underlying_device_char_type, codecvt, code_converter_traits_state_type>. this whould be the same mechanism as code conversion in the stdlib works (using std::codecvt specialization). Comments to my thoughts are very welcome. --- Thomas

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Re: [boost] [log] Boost.Log Review...
by Sean Chittenden 14 Mar '10

14 Mar '10

>> The above wasn't explicitly distilled in the documentation in a >> single place, but I think future developers would find it very useful >> to see that spelled out explicitly. Given the extremely modular >> design of the library, I understand why the docs are the way they are >> and know that some of this is touched on in the Design Overview, but >> until I became very competent with the library, the documentation >> seemed too abstract. Despite the importance of logging, becoming a >> logging expert was tangential to the problem I was trying to solve >> and I would have personally found the above summary very useful. > > Well, that summary may describe your use case very well, but it is by no > means complete with regard to Boost.Log as a whole. I would even say > it's misleading in some parts - in particular: "Loggers are collections > of Sinks" and "Think of channels as a Sink-level observer". Fair response. I think a more general way for me to classify my response/concern (instead of providing a loosely worded example) would be: "Which class does what and how do the classes relate to each other?" Right now answering that question results in a decent exploration of Boost.Log's code and documentation. It would have been useful to me, and likely future developers, to have the classes that comprise Boost.Log summarized so that conceptual map could have been more easily formed without having to dig in to the actual headers. Something similar to the contents of the Definitions page, but with architectural clues. http://boost-log.sourceforge.net/libs/log/doc/html/log/defs.html As an example, expanding on the Sinks definition from above: > Log Sink: A target, to which all log records are fed after being collected from user's application. It is sink's nature that defines where and how the log records are going to be stored. Maybe include something as brief as: > With a Log Sink, developers can modify the filtering and add additional backends. I consider myself a modestly competent user of boost, but still am getting parts of this wrong after over three months of using/digging in to Boost.Log. >> A hindsight 20/20 architecture and terminology for Boost.Log could be >> simplified in terms of: > > What is "20/20"? I'll continue my answers assuming that the following > was your understanding of the current Boost.Log architecture. Correct. The contents of this email has evolved from sometime around mid-January or whenever I learned that Boost.Log was going to be reviewed and accepted. It also crudely mirrors my understanding of the library as I went through the development process of utilizing the library. >> *) Log Record pre-conditions. Sinks control whether or not a Log >> Record is to be generated > > Looks like you're confusing sinks with filters. Also, don't forget about > the global filter. I became sloppy with my terminology. Filters are stored in Sinks and the Global core. Speaking of filters, yesterday I stumbled across a feature request: > Program received signal SIGABRT, Aborted. > 0x00007fff81de2fe6 in __kill () > (gdb) bt > #0 0x00007fff81de2fe6 in __kill () > #1 0x00007fff81e83e32 in abort () > #2 0x00007fff81e03de2 in _Unwind_Resume () > #3 0x00000001000a3b1c in main (argc=1, argv=0x7fff5fbff338) at /tmp/foo.cc:267 If I wrap everything in a boost exception, I get: > exception: /usr/local/include/boost/log/filters/attr.hpp(134): Throw in function (unknown) > Dynamic exception type: N5boost16exception_detail10clone_implINS0_19error_info_injectorINS_12log_mt_posix13missing_valueEEEEE > std::exception::what: Requested attribute value not found It'd be nice if the error message were able to somehow include the string representation of the value (attribute) it wasn't able to find. Turns out it was a type-o so I had an unregistered attribute, but the type-o would've been very easy to identify if it were included in the error message someplace (instead it took a fair amount of manual investigation and backtracking to figure out it was a filter searching for an attribute that didn't exist). [snip useful responses/corrections ] >> Observers could then be placed on Sinks that would stamp Log Records >> with Severities, or Channels, or in whatever hodge-podge >> configuration the developer wanted and such examples would be very >> cookbook. > > Now that you presented a code snippet, your suggestion makes more sense > to me. Let me express my thoughts on it in two parts: > > 1. Custom log records. Yes, the model of "mandatory" attributes look > promising. It could, at least, partially solve the problem of possible > library misconfiguration that was highlighted in another review. I > imagine that some kind of log record prototype (or factory) should be > defined by the user in order to be able to construct log records with > the specific set of attribute values. Filters and formatters could then > request these mandatory attribute values without having to worry about > their absence. Lookup performance may also be higher, but I doubt it > will be compile-time. The idea is quite vague now but after some > thinking over it might become a good addition to the library. > > 2. Designing sinks (and the core, I presume) after the log records. No, > that looks unacceptable to me, at least for what Boost.Log tries to > achieve. This would introduce too much coupling between the logging side > of the library (which tends to be exposed to many parts of the > application) and the consuming side (which tends to be configured in a > single place of the application). To my mind, these sides of the library > should be maximally decoupled. Also, it's not clear how to support > multiple log record types in such a design. >> *) Global loggers vs. per-object references to singletons > > Not sure I understand. Is it better to have global objects that reference singletons: > typedef boost::log::sources::severity_channel_logger_mt<levels::severity_level> logger_t; > > BOOST_LOG_DECLARE_GLOBAL_LOGGER(default_log, logger_t); > BOOST_LOG_DECLARE_GLOBAL_LOGGER_CTOR_ARGS(stats_log, logger_t, (boost::log::keywords::channel = "stats")); or per object references to logging singletons: > typedef boost::shared_ptr< boost::log::sinks::synchronous_sink< boost::log::sinks::text_ostream_backend > > console_sink_t; > typedef boost::shared_ptr< boost::log::core > logger_core_t; > > struct my_obj { > my_obj(logger_core_t& logger) : lg(logger) {} > void foo() { BOOST_LOG(lg) << "log msg"; } > logger_core_t& lg; > } > > int main() { > console_sink_t cerr_sink; > cerr_sink = boost::log::init_log_to_console( > std::cerr, > boost::log::keywords::filter = boost::log::filters::attr< int >("Severity") >= warning, > boost::log::keywords::format = "%TimeStamp%: %_%", > boost::log::keywords::auto_flush = true); > my_obj o(boost::log::core::get()); > o.foo(); > } ... I think that example's right. >> *) Channel severity loggers example > > That example wouldn't be much different from the ones in sections about > severity_logger or channel_logger. But I'll add a code sample. Where I spent time with this was figuring out how multiple chan severity loggers interacted with the core and how my app was supposed to interact with the distinct loggers, which were linked in to the core, behind the scenes. > typedef boost::log::sources::severity_channel_logger_mt<levels::severity_level> logger_t; > BOOST_LOG_DECLARE_GLOBAL_LOGGER(default_log, logger_t); > BOOST_LOG_DECLARE_GLOBAL_LOGGER_CTOR_ARGS(lg1, logger_t, (boost::log::keywords::channel = "chan1")); > BOOST_LOG_DECLARE_GLOBAL_LOGGER_CTOR_ARGS(lg2, logger_t, (boost::log::keywords::channel = "chan2")); > #define LG1_WARN BOOST_LOG_SEV(lg1::get(), log_severities::warn) > #define LG1_INFO BOOST_LOG_SEV(lg1::get(), log_severities::info) > ... > LG1_INFO << "info msg"; >> *) Setting up an initial console logger as >> line one in main() > > Hmm. Ok, I'll add something about that to the tutorial. Easy to do (see above), but I didn't see anything that said, "it would be wise to do this first and then remove your console sink after you setup your logging environment." Initially I disregarded the init_to_console() convenience functions while reading the docs, and it wasn't until I started dealing with error messages that weren't being logged to a file because my logging setup routines hadn't been completed (or had failed for some reason due to FS perms), that I suddenly took note of needing to get console logging working first. >> *) Changing a backend filter at a later date > > Just call set_filter on the backend, that's all. This was one of the areas where there were lots of ways that I could do it, but I couldn't tell which was the right way. libs/log didn't suggest a preferred mechanism or right way to do it. >> *) Using async logging for INFO level logs, but switching to sync for >> CRIT errors. > > You can register two sinks - one synchronous and one asynchronous, and > set their filters accordingly. Ah, clever way of handling that. >> *) Obtaining the severity of a particular logger > > You mean, the default severity? There's no public API for this, but > there's a protected function default_severity in the logger feature. Why > would you need it? Internally you're using spirit for log record filtering, so it's impossible from what I can tell to do that inside of Boost.Log. Having a way of poking at a sink to obtain information about its runtime status. Using the above console sink as an example: > typedef boost::shared_ptr< boost::log::sinks::synchronous_sink< boost::log::sinks::text_ostream_backend > > console_sink_t; > console_sink_t cerr_sink; > cerr_sink = boost::log::init_log_to_console( > std::cerr, > boost::log::keywords::filter = boost::log::filters::attr< int >("Severity") >= warning, > boost::log::keywords::format = "%TimeStamp%: %_%", > boost::log::keywords::auto_flush = true); > > std::cout << "Current Severity Level: " << /* or something like this */ cerr_sink->filter_severity() << std::endl; I ended up adding this to my application's surrounding code. >> *) How do you remove log events given a severity level at compile >> time. Currently this isn't explicit defined in the documentation >> like it is in Google's glog library: >> >> http://google-glog.googlecode.com/svn/trunk/doc/glog.html#strip > > The library has no direct means for that. Users can conditionally define > their logging macros, based on BOOST_LOG_SEV or pure C++ interface and > then enable or disable the particular logging statements from the source. *nods* I just didn't see anything in the docs to do this, which is why I ended up with the practice: > #ifdef RELEASE > # define LG1_WARN BOOST_LOG(null_log::get()) > #else > # define LG1_WARN BOOST_LOG_SEV(lg1::get(), log_severities::warn) > #endif null_log always filters everything sent to it. Probably less than ideal, but I couldn't think of a better way to handle this. >> *) Is there a way to set a bit in a Log Record that overrides a >> Sink's filter? For instance, there are certain events that I want to >> make sure go to the console 100% of the time without changing the >> severity of the log message. Do I just log twice? It'd be keen if >> Log Records could have a bit that could be set and would override a >> filter. >> >> bool log_to_console = true; BOOST_LOG_SEV_CONS(lg, warning, >> log_to_console)<< "my message"; > > You can set an attribute (say, "Emergency") for that record, and setup > filters so that whenever this attribute is present, the record is passed > on to the console backend. You mean a scope attribute? > boost::shared_ptr< attrs::mutable_constant< bool > > console_attr(new attrs::mutable_constant< bool >(false)); > lg.add_attribute("Console", console_attr); > BOOST_LOG(lg) << "Console is false by default"; > > { > BOOST_LOG_SCOPED_THREAD_ATTR(lg, "Console", true); > BOOST_LOG(lg) << "Console is true"; > } > > BOOST_LOG(lg) << "Console is false again"; Like that? >> *) It should be noted that the internal async log message queuing >> mechanism uses a vector and during very bursty logging activity that >> the vector can grow large in size and doesn't ever reduce in size. >> This is a known limitation and the use of a vector was chosen to >> facilitate atomic append operations for log records. Using a >> std::deque would be preferred for bursty applications that way space >> could be reclaimed easier, but as Andrey pointed out, it would >> require a full mutex which would reduce the performance of the >> library. > > There is no vector in the async frontends. The problem with the current > queuing mechanism is not the storage strategy but the lack of queue > boundaries. But I agree, I should have drawn attention to this aspect in > the docs. Will do. *nods* I brought this up in a private email w/ you and was satisfied with your answer, but thought it worth noting for others. As for the frontends having their own queue, with the way that async frontends work and their feed_records() call, I'd assumed the backend used a time-based mechanism to come by and pick up the log records stored in per-frontend TSS queues. Something where frontends atomically pushed records on, and the backend would atomically swap() the list of records off for sorting and processing by the backend. Just a point of confusion after reading: http://boost-log.sourceforge.net/libs/log/doc/html/log/detailed/sink_fronte… and I never dove in to the source to investigate further. >> *) I find the argument against Lazy Streaming of attributes to be >> weak. >> >> Current BOOST_LOG() expands to a for() loop where the contents of >> the for() loop aren't executed unless a Sink in a Logger accepts the >> record. >> >> So why can't Log Records have compile-time attributes that can be >> populated with typed attributes in a stream? >> >> And then be able to extract the compile-time attribute in a backend: > > Just as it is said in the rationale - the streaming expression is _not_ > executed until _after_ the filtering is done. And filtering already > involves attribute values, so there's no way to use these attribute > values you specified in the streaming expression. Besides, after the > view of attribute values is constructed, it is immutable, so nothing can > be added after the filtering is done. That's why I make the distinction between "log record preconditions," attributes that can be used in a filter, and "attributes," which is a catch-al term for data stored in a Log Record. I agree that it is impossible for streamed attributes to be used as preconditions, but streamed attributes act as an extremely convenient (from a syntax perspective) way of passing data to a backend for processing. >> *) Dovetailing on the above two points, a flush bit for a given Log >> Record would be very nice as well. 99.999% of the time async logging >> is desired, but in the 0.001% of the time when a Log Record must get >> out to disk, chances are that one Log Record every blue moon is >> disproportionally valuable compared to the normal Log Record. Having >> a flush() that doesn't return until the backend has fsync(2)'ed data >> would be really spiffy. >> >> BOOST_LOG_SEV(lg, warning)<< "My message"<< lg::flush; > > As I already noted, your mileage is too biased, at least. I, personally, > tend to use synchronous logging. But I do recognize that some kind of > flushing ability would be nice in case of async logging. I like the idea of using both async and sync sinks. It leaves me with a few questions, however: How does that work if they're both using the same text file backend? Will log entries still be ordered? > typedef boost::log::sinks::text_file_backend backend_t; > typedef boost::log::sinks::ordering_asynchronous_sink< backend_t > sink_t; > boost::shared_ptr<sink_t> sink(new sink_t( > boost::make_shared< backend_t >(), > keywords::order = logging::make_attr_ordering("LineId", std::less< unsigned int >()), > keywords::ordering_window = boost::posix_time::seconds(1))); Thanks again in advance. -sc -- Sean Chittenden sean(a)chittenden.org

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[SoC] Summer of Code Project Ideas
by Andrew Sutton 13 Mar '10

13 Mar '10

I'm officially soliciting ideas for student projects for this year's 2010 Summer of Code. If you're maintaining or contributing to a library and have some non-trivial items on a TODO list, then suggesting that as a possible student project may be a viable idea. Unlike the previous years, I think that proposing work on sandbox libraries would also be a good idea. There is a substantial amount of work in the sandbox that might be well-suited for student projects and eventual (I hope) acceptance to Boost. In general student projects should be tightly focused with a clear set of goals to getting their work integrated into a mainline development branch (be that trunk or sandbox). In general, we've noticed that ground-up libraries almost always fail to be integrated or released independently since they require a commitment longer than the summer. There are, of course, notable exceptions to this rule. If you are going to propose a student project, please keep in mind the following things: 1. Students tend to go away in the fall. 2. If their work isn't tended after August, then it's largely forgotten 3. If the student is gone and their work is forgotten, then the project didn't really succeed. If you write down or submit a project, please include your expectations for that work. And try to keep it small. That said, if you're too precise in the specifications, we'll going to get a couple dozen proposals that simply reiterate your expectations. But that's the nature of the beast. Good ideas for projects might be: == Data Structures and Algorithms== Admittedly these have little impact on overall quality of Boost, but make a nice sandbox for students to work in and can result in surprisingly good code. Over the course of the summer 1 or 2 related data structures or a family of related generic algorithms seems to make a nicely packaged project. ==Extensions for Existing Libraries== There are a number of Boost libraries that are very amenable to extension (e.g., BGL, GIL, Math, etc.). Basically any library that doesn't have a finite feature space. Non-intrusive changes (i.e., those that don't require hacking on the existing bits) typically make good summer of code projects. == Infrastructure Projects== Projects that aren't part of Boost, but help us improve the quality of Boost might make decent projects, but we've never had one proposed or accepted that I'm aware of. Remember, we can't accept documentation projects so "Write my documents" will not be a good student project (unfortunately ;) ==Applications of Boost== This is a little different... It might be a good idea to have students build real (example?) applications that use the Boost C++ Libraries. There are a number of real benefits to having students work in this space. First, these applications are very obvious clients of Boost. They can provide immediate feedback on issues with the interface, usability, correctness, performance, documentation, etc. Second, they might make really good examples of best practice for using Boost. Third, they probably make nice student projects. If you have any ideas, let's hear them. And remember, funded projects need mentors. Andrew Sutton andrew.n.sutton(a)gmail.com

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[log] Boost.Log Review...
by Sean Chittenden 13 Mar '10

13 Mar '10

YES, the Boost.Log library SHOULD BE ACCEPTED in to the Boost release distribution. Summary: *) Boost.Log isn't perfect and after having reviewed most of its alternatives, and having recently converted from using glog, I like the utility and architecture provided by Boost.Log the most. It comes close to solving all logging problems for everyone. Closing the gap of solving the last 5% between what Boost.Log does and what I ideally wanted was tedious and required me to develop a much higher level of understanding that I would have liked, but it was possible. *) In solving all logging problems for all people, Boost.Log's documentation is quite abstract. *) I would like to see the design of templates/classes flipped so that the starting point for interacting and beginning to use Boost.Log begins with customizing Log Records and ends with defining backends and backend filtering. This is a fundamental design choice, however and one that I'm willing to accept given the value that Boost.Log provides. *) I've been saving most of this feedback for the better part of two months now so excuse the length and rambling. Certain points of the library I struggled with and ultimately ended up begrudgingly resigned myself to accepting as "the way it is" vs. "the way it should be." *) My perspective on the Boost.Log is framed by the recent use of Google's glog library and in a previous life having written performance-oriented, binary logging libraries for high TPS systems (only in C, however, not C++). > - What is your evaluation of the potential usefulness of the library? Boost.Log quite useful and has the highest promise of any logging library that I am aware of because of its ability to accommodate the following common use case: Support asynchronous logging from multiple frontend threads with a backend able to order the output and send different messages to different files. If it weren't for the ability of this library to meet that specific design requirement, I would still be using Google's glog library. > - What is your evaluation of the design? The design is very modular. Too modular. So much so that the flexibility and required understanding is actually a barrier to entry to make use of the library (i.e. now that I'm using the library, I know more about the innards of Boost.Log than I would like or think is reasonable). After using this library for several months now, I have distilled a quick summary for those coming up to speed on how to use Boost.Log and its components. This is specific to how I'm using Boost.Log, but I think this is the desired use-case for most users of Boost.Log (esp since this is the common path for users of ASIO). - Your application is littered with Log Statements that are tagged with different Severity Levels - Log Statements consist of a Logger (a collection of Sinks), a Precondition (e.g. a severity) and Log Record instance data (most commonly a message) - Loggers are collections of Sinks (e.g. a file and the console) - Loggers conditionally accept Log Records if one of a Logger's Sinks returns true for a Precondition (e.g. only create a Log Record if the log statement's Severity Level greater than or equal to the Severity Level configured in the Sink) - Instructions required to create a Log Record won't be executed if a Sink doesn't accept a Log Record - Sinks can be configured to queue accepted Log Records (e.g. async frontends) before passing them to one or more Backends for printing (e.g. console text file, SNMP trap) The Boost.Log system can be configured to mutate individual Log Records through the manipulation of the following three types of information: - Channels represent a way of tying together a collection of related systems (e.g. security, network, application). Think of channels as a Sink-level observer that stamps the channel on a Log Record. - Severities represent the importance of a message (a Log Statement precondition that a Sink-level Observer could stamp a Log Record) - Attributes represent per-Log Record information (a string key/value in a Log Record instance) Backends can then format the output based on the Attributes of a particular Log Record. The above wasn't explicitly distilled in the documentation in a single place, but I think future developers would find it very useful to see that spelled out explicitly. Given the extremely modular design of the library, I understand why the docs are the way they are and know that some of this is touched on in the Design Overview, but until I became very competent with the library, the documentation seemed too abstract. Despite the importance of logging, becoming a logging expert was tangential to the problem I was trying to solve and I would have personally found the above summary very useful. While glog is a supper thin logging API, Boost.Log feels like a complete and modular logging system. In glog, seeing: VLOG(3) << "asdf"; Where 3 can/was a #define, the system ended up feeling very arbitrary and unstructured. A hindsight 20/20 architecture and terminology for Boost.Log could be simplified in terms of: *) Log Record pre-conditions. Sinks control whether or not a Log Record is to be generated *) Loggers. A container for zero or more Sinks *) Sinks. A frontend that queues Log Records *) Sink Compile-Time Attributes/Observers. Observers that are configured at compile time, augment Log Records, and stamp Log Records as they pass through the Sink (e.g. severity, channels, etc) *) Backends. A formatter that orders and writes Log Records from Sinks *) Log Records. A container of information that is populated by the user's application, Sinks and Backends (possibly Loggers as well) *) Log Record Compile-Time Attributes. Compile-time members of a Log Record struct *) Log Record Runtime Attributes. Key/Value members of a Log Record stored in a std::map (currently how Attributes are implemented) I'd imagine most developer would want async messaging between Sinks and Backends. Those that don't, could make use of a Sink Compile-Time Attribute that always sets the flush bit on a Log Record. > - What is your evaluation of the implementation? Generally speaking the internals of the implementation is pretty clean, especially given the size and various ways that Boost.Log can be cobbled together. Also in hindsight: the developer interface for interacting with the library could be improved by making Log Records the fundamental unit that everything hangs off of. Making log records easy to extend containers that carry domain specific information without std::map seems like a better design choice given how frequently developers will interact with Log Records. The use case of having log records that maintain stats that get pumped through a logging system struck me as particularly useful, but unnecessarily expensive with std::map. As was noted in other reviews, the cost of evaluating whether or not a Sink is going to accept a Log Record is of some concern. Figuring out a way to have the Log Record preconditions evaluated as quickly as possible should be important given the frequency at which logging code is/should be deployed in most applications. I remember reading someone else's benchmark saying that it was ~2500 instructions to evaluate whether or not a Sink should accept a given Log Record. For something that should macro expand to: for (logger::iter = logger.begin(); iter->accept(severity); ++iter) iter->stream() I haven't profiled, but when most accept() functions are doing: inline bool accept(SevT s) const { return s >= sev_filter ? true : false; } 2500 ops seems expensive to me. The notion of a "global logging core" bothers me. Having singletons of loggers and sinks in TSS is very good from a utility perspective. Admittedly I don't know how the global logging core is used beyond being a nob that can be turned to enable/disable logging, nor have I profiled it yet, but any centralized core bugs me in a highly threaded environment. Questions: Why does Boost.Log roll its own TLS/TSS support? boost/log/detail/thread_specific.hpp vs. boost/thread/tss.hpp There may be a very good reason, I just didn't see it when I was looking through the library. Can Log Records be pool managed somehow? *) Log Records I understand why std::map is used to store attributes (ease of use/flexibility), but at the same time, I do wish that frequently stored attributes could be baked in at compile time. This is my biggest gripe with the library, actually. I would like my application to err on the side of making use of compile-time information at the expense of the time required for compiling the source. Storing things in a std::map seems lazy and brutish, for the lack of a better description. Flipping things on its head so that Log Records define Loggers, Sinks and Backends would be ideal, IMHO, and would solve most of my gripes. This is a design decision, but the contents of Log Records is of more importance than the backends. Boost.Log appears to be designed from Backends to Log Records vs. Log Records to Backends, which is the way data flows through an application (this would be my preference). For example: // quick pseudo-code using MI to create my_log_record and downstream types typedef enum { info = 0, warn = 1, crit = 2 } severity_t; struct my_log_record : boost::log::record::attribute::map< std::string, std::string >, boost::log::record::attribute::severity< severity_t >, boost::log::record::attribute::message, boost::log::recordmy_app::log_record::attribute::src_port {}; typedef struct my_log_record log_record_t; typedef SinkT< log_record_t > sink_t; typedef LoggerT< sink_t > logger_t; typedef BackendT< sinkT > backend_t; Observers could then be placed on Sinks that would stamp Log Records with Severities, or Channels, or in whatever hodge-podge configuration the developer wanted and such examples would be very cookbook. *) Log Records are highly reused and seem like ideal candidates for a TLS freelist. > - What is your evaluation of the documentation? Pretty complete, albeit abstract. Lacks examples for customized records and a best practice guidelines. A few other suggestions for things that I had to hunt down or figure out: *) Global loggers vs. per-object references to singletons *) Channel severity loggers example *) Setting up an initial console logger as line one in main() *) Changing a backend filter at a later date *) Using async logging for INFO level logs, but switching to sync for CRIT errors. *) Obtaining the severity of a particular logger Outstanding doc questions: *) How do you remove log events given a severity level at compile time. Currently this isn't explicit defined in the documentation like it is in Google's glog library: http://google-glog.googlecode.com/svn/trunk/doc/glog.html#strip *) Is there a way to set a bit in a Log Record that overrides a Sink's filter? For instance, there are certain events that I want to make sure go to the console 100% of the time without changing the severity of the log message. Do I just log twice? It'd be keen if Log Records could have a bit that could be set and would override a filter. bool log_to_console = true; BOOST_LOG_SEV_CONS(lg, warning, log_to_console) << "my message"; Other comments: *) It should be noted that the internal async log message queuing mechanism uses a vector and during very bursty logging activity that the vector can grow large in size and doesn't ever reduce in size. This is a known limitation and the use of a vector was chosen to facilitate atomic append operations for log records. Using a std::deque would be preferred for bursty applications that way space could be reclaimed easier, but as Andrey pointed out, it would require a full mutex which would reduce the performance of the library. *) I find the argument against Lazy Streaming of attributes to be weak. http://boost-log.sourceforge.net/libs/log/doc/html/log/rationale/why_not_la… Current BOOST_LOG() expands to a for() loop where the contents of the for() loop aren't executed unless a Sink in a Logger accepts the record. From: boost/log/sources/record_ostream.hpp #define BOOST_LOG_STREAM_WITH_PARAMS_INTERNAL(logger, rec_var, params_seq)\ for (BOOST_LOG_AUTO(rec_var, (logger).open_record((BOOST_PP_SEQ_ENUM(params_seq)))); !!rec_var; rec_var.reset())\ ::boost::log::aux::make_pump_stream((logger), rec_var) So why can't Log Records have compile-time attributes that can be populated with typed attributes in a stream? BOOST_LOG_SEV(lg, warning) << "My log has an attribute src_port" << log_record_t::set_src_port(conn.src_port) << " this continues to append to the Log Record's message"; And then be able to extract the compile-time attribute in a backend: // Dashed out pseudo-code to make a point (I know the syntax is garbage in the src_port's formatter). typedef struct backend : boost::log::record::base_record { typedef int src_port_type; int src_port; } record_t; typedef boost::log::sinks::text_file_backend< record_t > backend_t; b->set_formatter( fmt::stream << fmt::attr<unsigned int>("LineId", keywords::format = "%08x") << " Src Port: " << fmt::attr< record_t::src_port_type >(record_t::src_port) ); *) Dovetailing on the above two points, a flush bit for a given Log Record would be very nice as well. 99.999% of the time async logging is desired, but in the 0.001% of the time when a Log Record must get out to disk, chances are that one Log Record every blue moon is disproportionally valuable compared to the normal Log Record. Having a flush() that doesn't return until the backend has fsync(2)'ed data would be really spiffy. BOOST_LOG_SEV(lg, warning) << "My message" << lg::flush; As is, you have to call: sink->feed_records(::boost::posix_time::seconds(0)); which isn't as elegant and I don't believe actually signals to the backend that data needs to be flushed to disk (it simply drains the frontend). Developers that want synchronous logging could define an observer that always sets the sync bit and would almost certainly be optimized away at compile-time. > - Did you try to use the library? With what compiler? Did you have any problems? FreeBSD 7+ and Darwin. GCC 4.2.1, gcc 4.3 gcc 4.4. TIP in subversion has been working well for me. RC4 was problematic due to bjam configuration problems. > - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? Developed a reasonably in-depth understanding of the internals and its use. > - Are you knowledgeable about the problem domain? Sufficiently adept in the problem domain. Parting thoughts: Like I said in the first paragraph, this library should be accepted in to Boost because it's the best that I've evaluated and see available on the landscape. My compliments to Andrey, and likely Trojo as well. All of my critical feedback is hindsight 20/20 after having successfully integrated Boost.Log in to my application. I am happy with Boost.Log though do see room for improvement in the future. Forward thinking: The more times I have to tweak and revisit logging, for whatever reason, the more convinced that a better and more elegant design would result if Backends, Sinks, et al were defined in terms of Log Records. If there is a Boost.Log2, I would love to see the architecture flipped on its head as suggested. I believe such an architecture would: *) improve the evaluation of a Sink's preconditions for accepting/creating a new Log Record *) allow Log Records to contain bits that are set by observers and are propagated through a Log Record's life-cycle back to the Backends *) result in easier application specific logic (e.g. flush or console redirection) *) improve performance when preconditions are evaluated *) improve performance because fixed sized Log Records could be memory managed on thread specific pools *) allow observers to be chained together components that would be easier to setup and manipulate; and *) could be used to allow data to stream to a backend (namely application stats) Further, by constraining the scope of what Boost.Log is capable to a more rigid/fixed architecture that gets optimized at compile time, the library would be easier to understand and use (e.g. change the design so that not all Sinks or Backends accept all Log Records). Hopefully someone finds this retrospective useful in the future. -sc PS I started to put my money where my mouth is and cobbled together something that crudely demonstrates Log Records -> Backends, but came up short when getting streaming attributes to work due to a lack of time available to focus for getting an overloaded operator<<() to work. The sample can be found here if anyone is interested. Discussions of this should be taken offline since it's tangential to the current Boost.Log review process. http://codepad.org/8ACp0obH -- Sean Chittenden sean(a)chittenden.org

2 1

Status of (boost) lockfree?
by Emil Dotchevski 13 Mar '10

13 Mar '10

I decided to give the lockfree library that's currently in the review queue a try. On MSVC 9.0, I'm getting this error: boost\lockfree\detail\cas.hpp(129) : error C2440: 'reinterpret_cast' : cannot convert from 'const boost::uint64_t' to 'LONGLONG' The compiler then continues to say: Conversion is a valid standard conversion, which can be performed implicitly or by use of static_cast, C-style cast or function-style cast Am I missing a configuration macro, or is this a valid compile error? Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

4 5

[serialization] portable non-floating-point binary library.
by Mostafa 13 Mar '10

13 Mar '10

Hi all, If adding floating point support to portable binary serialization is so hard/time-consuming, why not just have a portable non-floating-point binary library in boost as an intermediate step? Surely it would be more convenient for the community, instead of having to build in or make a library out of the files in https://svn.boost.org/trac/boost/browser/trunk/libs/serialization/example. (I did search the archives and couldn't find any answers, if I missed some threads please point them out.) Thanks, Mostafa

1 0

suggestion on assertion macros
by DE 12 Mar '10

12 Mar '10

there were a discussion recentrly about verifying arguments of assertion macros while checks are turned off i've got an idea of how to check the argument(s) and guarantee zero code size and runtime overhead suppose we have a canonical macro 'assert()' while compiling with NDEBUG macro defined it expands to nothing which may cause annoying compiler warnings (like 'var isn't referenced') assert() checks a condition i.e. the argument must be convertible to bool then we can write #define assert(cond) sizeof(cond) but to check if the arg converts to bool we can write something like #define assert(cond) sizeof(bool(cond)) which may or may not expand to some code (i.e. machine instructions) to ensure zero overhead i suggest the following scheme: #ifdef NDEBUG typename<size_t s> struct dummy_for_assert; #define my_assert(cond)\ typedef dummy_for_assert<sizeof(bool(cond))> typedef_dummy_for_assert #elif #define my_assert(cond) assert(cond) #endif i hope you got the idea by the way the typedef may be enclosed in a scope in order not to mess around: #define my_assert(cond)\ do {\ typedef dummy_for_assert<sizeof(bool(cond))> t;\ } while(false) although all this looks like a big kludge i believe more advanced programmers would make it work very well (and even make it idiomatic) if that already has been discussed sorry for wasting your time -- Pavel

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[repost][multiarray] Bug with boost::detail::multi_array::array_iterator on MSVC 2010RC?
by Jesse Perla 12 Mar '10

12 Mar '10

Sorry for the repost, but I am pretty sure this is a bug with the MSVC standard library integration to multi_array. It could also be related to boost::iterator The following code worked on MSVC 2008, Intel 11.1 on Windows, and MinGW, ... but is failing to compile on the MSVC 2010RC. I tested this against boost 1.42 and the boost trunk from SVN. #pragma warning(disable:4996) //Tough to see errors otherwise. #include <boost/multi_array.hpp> int main(int argc, char* argv[]) { boost::multi_array<double, 3> f_values(boost::extents[5][6][7]); //A boost::multidimensional object boost::detail::multi_array::sub_array<double, 2> sub_f = f_values[2]; //Works boost::multi_array<double, 2> sub_f2 = f_values[2]; //Fails on MSVC10, works on all others } ////////////////// The problem here is with the constructor in multi_array.hpp around line 334. It uses an std::copy, However, if I replace the: std::copy(rhs.begin(),rhs.end(),this->begin()); with the (godawful) direct iteration: auto p_rhs = rhs.begin(); auto p_this = this->begin(); while(p_rhs < rhs.end()) { *p_this = *p_rhs; ++p_rhs; ++p_this; } Things compile fine. Also note, that this same problem with the std::copy happens in pretty much every other constructor/place it is used in this library. (i.e. all over the place, so this 'hack' is pretty useless). It appears to me that the MSVC's STD implementation isn't finding a match a std::copy overload impl with the iterators as: Input iterator as: boost::detail::multi_array::array_iterator<double,const double *,boost::mpl::size_t<2>,boost::detail::multi_array::const_sub_array<double,1>> Output iterator as: boost::detail::multi_array::array_iterator<double,double *,boost::mpl::size_t<2>,boost::detail::multi_array::sub_array<double,1>>, I have attached my test files. Any ideas or patches would be appreciated

2 2

How to specify Boost headers location properly
by Mateusz Loskot 11 Mar '10

11 Mar '10

Hi, I'm trying to learn what is, let's say, canonical form of configuring Boost headers location in Jamfiles of test and example programs for: 1) Libraries that live inside Boost tree (SVN trunk) - Boost libraries. 2) Libraries that are close-to-Boost, it is Sandbox, libraries being reviewed and libraries already reviewed and accepted but not yet included in Boost tree In the case 1), I assume it's required that a library is configured to use headers from the same Boost tree where it is actually included. In the case 2), I assume that it's recommended to configure a library in such way that allows compilation in two ways: a) user copies library to Boost tree and compiles, i.e. examples, by executing bjam inside BOOST_ROOT/libs/LIBRARY/example b) user does not copy library to Boost tree, but keeps it externally and still can do: cd BOOST_ROOT/libs/LIBRARY/example bjam I was explained by folks on #boost channel, that there is no requirement for user to: - set environment variables like BOOST_ROOT - or to set global <include> requirements in user-config.jam, like this: project : requirements <include>/path/to/boost/root ; As I was told, the only entry in user-config.jam related to location of Boost headers should be use-project boost : /path/to/boost/root ; I'm looking at various Jamfiles in trunk and sandbox and I'm a bit confused. For 1st example for the case 1), in trunk/libs/accumulators/example/Jamfile.v2, Boost headers are located by relative path and mysterious $(BOOST_ROOT) exe example : main.cpp : <include>../../.. <include>$(BOOST_ROOT) ; For 2nd example of the case 1), in libs/program_options/example/Jamfile.v2, there is no <include> or <source> requirement configured, so AFAIU, it means global Boost Jamroot takes care of setting headers location. For 1st example for the case 2), it is ITL library that was submitted to review, not yet in Boost tree, I see similar double-include trick in Jamfile of examples: https://svn.boost.org/svn/boost/sandbox/itl/libs/itl/example/Jamfile.v2 exe overlap_counter : overlap_counter_/overlap_counter.cpp : <include>../../.. <include>$(BOOST_ROOT) ; I have seen similar pattern for other libraries in Sandbox. It tells me that either these libraries can be build *only* from within Boost tree or, if user wants to build them from outside Boost tree, it is required to specify the mysterious BOOST_ROOT which in fact should not be required at all [1] [1] http://lists.boost.org/boost-users/2004/09/7755.php It also suggests me that for cases as the one illustrated with Jamfile from the ITL library, if a user doesn't copy a library in to Boost tree or doesn't set BOOST_ROOT or doesn't put the hack of hard-coded Boost headers path as <include> in user-config.jam file, then it is not possible to compile such library (or its examples or tests, if it's headers-only). I started to ask myself: How folks compile libraries while reviewing if these libraries are configured to locate headers with <include>../../.. <include>$(BOOST_ROOT) Does it mean a library submitted to review (or reviewed and accepted but not yet included to Boost) are required to be configured as living in Boost tree? Or, does it mean everybody makes "unofficial" configurations to environment like setting $BOOST_ROOT or hacking user-config.jam. Now, here comes final question derived from all the elaborate introduction: If I assume that a user installs Boost without making any of the not recommended hacks to his environment (let's say, only puts use-project boost directive to user-config.jam), then How should I configure Jamfiles of Boost Geometry (examples and tests) to locate Boost headers in the following two situations: 1) User copies Boost Geometry in to Boost tree and compiles examples and tests 2) User keeps Boost Geometry outside Boost tree and still should be able to compile examples and tests using his Boost installation. By the way, I have started discussing this [2] problem on Boost Geometry mailing list but there are still some confusions [3] that make this issue far from clarified. [2] http://lists.osgeo.org/pipermail/ggl/2010-March/000657.html [3] http://lists.osgeo.org/pipermail/ggl/2010-March/000662.html I'd appreciate if someone here could teach me, once and for good, how to make it right. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org

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Participation in google summer of code 2010
by vikas kushwaha 11 Mar '10

11 Mar '10

I would like to participate in gsoc 2010. I was thinking of audio library for boost, as a project. Will it be a good project to work upon. Thanks in advance.

2 1

[Log] Review Results
by Roland Bock 11 Mar '10

11 Mar '10

Hi, here are my review results. I have organized it in two parts. A relatively short one answering the formal review questions and a second part that lists a lot of additional details. Attached is a short program which contains some of the tests I did. - Should the library be accepted? ================================= YES, but some things should be fixed first (see also details below): - Compiler warnings: I get tons of them. Zero should be the goal. - Completeness of documentation: Some things are simply missing and can only be found in the code - Compile time for the library - A lot of details are listed below. Of course, I would like to see all of them addressed, but my vote does not depend on every single one of them. - What is your evaluation of the design? ======================================== Very flexible, very modularized. I have two concerns, both explained in more detail below. a) In some aspects, it is too flexible, I think. This makes it hard to document (which can be seen in the current documentation) and hard to test (the latter is just me guessing). b) It is easy to use it in the wrong way, which leads to exceptions and lost log records, possibly after hours of running, probably in some rare and potentially critical situation. It would be better to somehow prevent the wrong usage at compile time. - What is your evaluation of the implementation? ================================================ I looked at the code only briefly, but what I saw looked good to me (see below). - What is your evaluation of the documentation? =============================================== Very nice examples, very well motivated tutorial. Good overview on details. Was good to read to get an idea of how the library can be used. But (at least for me) it was sometimes tough to combine the information given in examples to the things I want to do myself. Mostly this was because some information is missing (or too well hidden for me). I admit that I got lost on the last few pages, but that was probably due to me not actually experimenting with all of it. See below for specific remarks. - What is your evaluation of the potential usefulness of the library? ===================================================================== Very useful! Logging is one of the core aspects of almost all software. And it is not nearly as easy as it seems at first glance. Thus, it is very useful to have a well designed, well documented, well tested and well supported log library. - Did you try to use the library? With what compiler? Did you have any ====================================================================== problems? ========= I compiled the library (the version from the SVN trunk, because the packaged version from sourceforge did not compile on my system). I also did some experiments to see how easy or hard it was to transfer the information from the documentation to some "real" code. I stumbled over quite a few details, but am convinced that I could use the library, soon. The most annoying problem were the compile warnings I mentioned above. Ubuntu-8.04 64bit, gcc-4.2.4, boost-log from SVN trunk, boost-1.42 - How much effort did you put into your evaluation? A glance? A quick ===================================================================== reading? In-depth study? ======================== I spent several hours reading the documentation and several hours of experimenting (see details below), about 12 hours in total (which includes writing this review). - Are you knowledgeable about the problem domain? ================================================= I wrote the log library which is being used by some 100 components in our company for about two years now. It is based on POCO library (pocoproject.org) Before writing it, I analyzed several log other libraries too, of course. So I would not consider myself an expert, but not really a newbie, either :-) ------------------------------------------------------------------------ MORE DETAILS ------------------------------------------------------------------------ Missing Features: ================= Maybe I overlooked it, but I did not find the following: - Have several sinks share a formatter: The programs in my company typically produce several log files: - debug: Contains everything - warn: Contains everything which is at least a warning - error: Contains everything which is error or fatal Messages in all files are formatted in the same way. I understand that I could create several file sinks and each is given its own formatter. But that would mean that the same formatting is done several times. Is there a way to have several sinks with different filter but sharing the log records? Compiling: ========== - Library Code: As mentioned in an earlier mail, it takes awfully long to compile the library, which is due to one file: formatter_parser.cpp The parsing is based on Boost.Spirit (classic) and takes 20 minutes to compile on my maschine (Ubuntu-8.04 64bit, gcc-4.2.4, Intel Quad Core, 2.5GHz) I don't know how much can be gained by switching to Spirit 2.1. But I am sure a way has to be found to accelerate the compilation. Otherwise, users will do what I did: Get nervous about the long compilation time and tend to press Ctrl-C before the work is done. - My Code: All of the code in our company is compiled with the following settings (gcc-4.2.4): -Wall -Wreorder -Wnon-virtual-dtor -Wno-non-template-friend -Woverloaded-virtual -Wsign-promo -Wextra -fvisibility=hidden We strive for code that compiles without warnings, but with boost.log, I get tons of warnings. What I have seen so far should be easy to get rid of. But I will not be able to use the boost.log library unless the warnings are taken care of. Debugging: ========== - I tried to add a timestamp to each written record. I used core->add_global_attribute("TimeStamp", boost::make_shared< attrs::local_clock >()); backend->set_formatter( fmt::stream << fmt::date_time< std::tm >("TimeStamp") << ": [" << fmt::attr< severity_level >("Severity") << "] " << fmt::message() ); This compiled, but when I ran my program, I got an exception message which did not really tell what was wrong: ----------------- terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::log_mt_posix::missing_value> >' what(): Requested attribute value not found ----------------- I think, at least it should tell which attribute value was not found. But the real reason for the exception was that the types of the attribute and the attribute value did not match. - Is there a way to get to these exceptions earlier? As of now, in the example above, the exception is thrown when a logger is used. This is much too late. I need to initialize logging and then be sure that logging will work for the components that use it (within limits of course, e.g. filesystem being full). But mis-configurations like above must be detected before the real work is done in the components using the log system. For instance when constructing the logger. - Of course, best would be to prevent such stuff at compile time (no idea how, though) Design: ======= - Flexibility: To be honest, in some aspects, I would have preferred to see less flexibility, for two reasons: a) the documentation effort rises and I suspect that the missing completeness of the documentation is partly a result of over-flexibility b) the testing effort rises (I guess). It will be hard to make sure that everything works as expected. An example is log record formatting via Boost.Lamda, Boost.Format, String Templates, Custom-Formatting, which is all shown by example in the tutorial, but the detailed description of Formatters does not even mention String Templates or Custom Formatting. - Easy to misuse: If your formatter requires a severity and the logger does not add one to the log record or adds a severity of the wrong type, using that logger results in an exception, see attached code. It is unlikely that this will happen in some part of the code which is executed frequently, because the developer would certainly notice. But what if someone would add a non-matching logger at some rarely executed but critical code section? Not only would the code fail with an exception, it would also fail to log the message! As of now, I would have to provide some factory method which produces loggers for anyone who needs one. And no logger is ever to be constructed otherwise. Just to make sure that everybody uses a logger that actually produces digestible log records. I can live with that, but I do not consider it a good solution. Code Quality: ============= - Readability: I did not read through all the code, and none in very much detail, but the parts I looked at, looked well organized and readable. - Names: - namespace trivial: I admit that I don't like that, especially since its content is not exactly trivial. Easy, basic or default maybe, I don't know. But not trivial :-) Documentation: ============== Very nice examples, very well motivated tutorial. Good overview on details. Was good to read to get an idea of how the library can be used. But (at least for me) it was sometimes tough to combine the information given in examples to the things I want to do myself. I admit that I got lost on the last few pages, but was probably due to me not actually experimenting with all of it. Some things should be looked into, though: Build process: - it would be nice, if the default build configuration were documented - I wonder which build configuration will be used when the library is included in boost? Tutorial: - Trivial logging with filters: The "Tip" that streaming expressions are not evaluated if the message is filtered should probably be a warning of potential hazard. It is certainly a good feature, but the semantics of the macros are not immediately obvious so I would give the "Tip" a more critical nature. - none of the code examples is complete. They are missing the namespace declarations documented in the introduction, at least. While brevity is good, it would be very helpful to have complete, compiling examples in the tutorial Missing Documentation: - Not all include files are mentioned. This makes it unnecessarily tough to follow the examples. For instance, boost/log/utility/empty_deleter.hpp is required to use logging::empty_deleter. I could not find this information in all of the turorial and details. Another, maybe even more critical example: The BOOST_LOG macro is defined in boost/log/sources/record_ostream.hpp Again I did not find that information in the tutorial. - I understand that I can use my own set of severity levels. It is well documented how to filter messages using these severity levels. But I have no idea how to format messages with these severity levels? I do not want the number, I'd like a string, of course. I looked it up in the trivial.hpp, but it should be part of the documentation. - Maybe I missed it, but I did not find an overview of the log rotation options, including a description of the placeholders in strings. Specific question: Can I tell the log rotation to take place at midnight (regardless of the amount of data which is being logged)? I would like to stress this last item one more time: The examples are excellent, but they should be accompanied by more formal tables which show the complete set of options, e.g. which placeholders can be used in a filename format or a list of public (protected?) member functions of a logger. For instance, I found the logger::strm() member in examples only.

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[SoC] project ideas: BigInt
by Andrew Sutton 11 Mar '10

11 Mar '10

I put BigInt back on the project ideas board with a caveat that some approaches aren't viable due to licensing concerns and that successful proposals should include discussion of those concerns. Out of curiosity, do we have a summary of those licensing issues and other concerns for this project? I haven't had the time to dig through archives. If we're accepting for BigInt, should also solicit a project for arbitrary precision floats? What about a fixed point data structure? Andrew Sutton andrew.n.sutton(a)gmail.com

4 6

[log] Review attempt
by Roland Bock 11 Mar '10

11 Mar '10

Hi, good to see that boost.log is being formally reviewed! From what I read in the documentation so far, I am really looking forward to seeing the library included in boost. I sure want to do some tests, hoping to replace our current logging system, soon, but today I can only answer the following review item: - Did you try to use the library? With what compiler? Did you have any problems? Yes, I tried and failed to compile it. Details are below. Platform: Ubuntu 8.04, 64bit, g++ 4.2.4 Intel QuadCore 2.5GHz, 8GB Ram Compilation: ============ Sounds embarassing, but I failed to compile the library. I copied the folders boost, lib and doc from boost-log-RC4 to boost_1_42_0, called ./bootstrap.sh ./bjam -d+2 --build-dir=build --with-log --prefix=/my/install/path link=shared runtime-link=shared install All looked well until this point: gcc.compile.c++ build/boost/bin.v2/libs/log/build/gcc-4.2.4/release/threading-multi/filter_parser.o "g++" -ftemplate-depth-128 -O3 -finline-functions -Wno-inline -Wall -pthread -fPIC -fno-strict-aliasing -DBOOST_ALL_NO_LIB=1 -DBOOST_DATE_TIME_DYN_LINK=1 -DBOOST_FILESYSTEM_DYN_LINK=1 -DBOOST_LOG_DLL -DBOOST_LOG_SETUP_BUILDING_THE_LIB=1 -DBOOST_LOG_SETUP_DLL -DBOOST_LOG_USE_NATIVE_SYSLOG=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_THREAD_POSIX -DBOOST_THREAD_USE_DLL=1 -DDATE_TIME_INLINE -DNDEBUG -I"." -c -o "build/boost/bin.v2/libs/log/build/gcc-4.2.4/release/threading-multi/filter_parser.o" "libs/log/src/filter_parser.cpp" The process cc1plus was running about 20 minutes (100%CPU, moderate RAM usage) before anything else happened. Then, after lots and lots of very long error messages, it continues like this: ...skipped <pbuild/boost/bin.v2/libs/log/build/gcc-4.2.4/release/threading-multi>libboost_log.so.1.42.0 for lack of <pbuild/boost/bin.v2/libs/log/build/gcc-4.2.4/release/threading-multi>attribute_set.o... Hmm. Not sure how to proceed. Should I send the whole bunch of error messages to the list as an attachment? Regards, Roland

5 13

Summer of Code 2010
by Vladimir Prus 11 Mar '10

11 Mar '10

Folks, Google Summer of Code will continue in 2010, and I believe the organization applications will be accepted starting March 8. Are we going to participate, and if so, who is taking responsibility for submitting the application? Thanks, Volodya

15 41

[log] Boost.Log formal review
by Ralf Globisch 10 Mar '10

10 Mar '10

Firstly, thanks for the wonderfully written library Andrey. * Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Yes, definitely! The general review checklist is provided below: * What is your evaluation of the design? Good design and simple enough to use. Highly flexible and not too complex. * What is your evaluation of the implementation? Did not consider the implementation. * What is your evaluation of the documentation? Detailed documentation that details rationale, design decisions, tutorials, etc. AFAIR there was no link to the examples in the documentation, that perhaps could be added (if it isn't there already) to make it easier to get started. * What is your evaluation of the potential usefulness of the library? A logging library is a necessary debugging tool and is very useful if not neccessary in any application. A "standard" (and boost is as close to standard as it gets) logging library is long overdue. After searching extensively for a suitable logging library, I finally came across this library which satisfied all my demands. I had previously implemented my own logging library for use in a project which had specific requirements and this library met all of them and is far superior. However I should also mention that I have only recently compiled and tested the library using the provided examples as a quick guide to get going so my experience with the library is somewhat limited. * Did you try to use the library? With what compiler? Did you have any problems? Briefly, used some of the examples to get started. I would have liked to play with the library more but am submitting this review now due to limited time constraints. - Compilation: Compiled under Windows 7, Visual Studio 2008 without any problems * How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? I compiled the library and built a couple of the examples, changed parameters just to get an introductory feel. By no means an in-depth study. Read through the documentation. For me most importantly, I compared the functionality of the log library to the functional requirements of a logging library I wrote for use in a commercial real time streaming system and this library met all requirements and is far more flexible and superior to my own implementation. * Are you knowledgeable about the problem domain? Somewhat, I have written my own logging library although nowhere near as extensive as this one. Also, I am fairly new to boost (started using aspects of boost less than two years ago) and from reading through this mailing list I still have a lot to learn about c++/design, etc. From a previous post about the log library: > FWIW, I consider this library to be > http://en.wikipedia.org/wiki/Data_logging > and not the database/filesystem logging stuff, > http://en.wikipedia.org/wiki/Write_ahead_logging Agreed. This library allows one to log all application-related information in a simple manner and provides an effective debugging tool. Regards, Ralf -- This message is subject to the CSIR's copyright terms and conditions, e-mail legal notice, and implemented Open Document Format (ODF) standard. The full disclaimer details can be found at http://www.csir.co.za/disclaimer.html. This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. MailScanner thanks Transtec Computers for their support.

1 0

[SoC] [Asio] User input
by Andrew Sutton 10 Mar '10

10 Mar '10

A couple of years ago there was an SoC idea to extend Asio with user-input. This seemed like it may have been a pretty good idea. I think it would be great if, minimally, Boost provided some mechanism of interacting with a shell in raw input mode--in a well-designed and portable way, of course :) Did any work actually occur in this direction? Does it still seem like a viable SoC project? Would anybody be willing to mentor it? Andrew Sutton andrew.n.sutton(a)gmail.com

4 7

[bimap] Includes serialization headers even if BOOST_BIMAP_DISABLE_SERIALIZATION is defined
by Christian Holmquist 10 Mar '10

10 Mar '10

Hello, I noticed this issue with boost 1.42, but it might have been there for a while. Quite a few headers have #include <boost/serialization/nvp.hpp> I think the above should be guared with #ifndef BOOST_BIMAP_DISABLE_SERIALIZATION #include <boost/serialization/nvp.hpp> #endif Regards, Christian

2 2

[signals2] missing Jamfile and compile errors with VC8
by Michael Caisse 10 Mar '10

10 Mar '10

I was surprised to not find a Jamfile in the libs/signals2/example directory. Please find an example below. The reason I headed toward the examples is that I'm having trouble with this type of line and VC8: typedef boost::signals2::signal<void ()> signal_t; In fact doc_view_acm.cpp will not compile because of it. disconnect_and_block.cpp also has compilation errors. Results verified in 1.41 and 1.42 with VC8 and gcc 4.3.2 --------------------------------------------------------- # Boost.Signals2 Library project : requirements <source>/boost//headers ; exe hello_world_slot : hello_world_slot.cpp ; exe hello_world_multi_slot : hello_world_multi_slot.cpp ; exe ordering_slots : ordering_slots.cpp ; exe passing_slots : passing_slots.cpp ; exe extended_slot : extended_slot.cpp ; exe custom_combiners : custom_combiners.cpp ; exe disconnect_and_block : disconnect_and_block.cpp ; exe doc_view : doc_view.cpp ; exe doc_view_acm : doc_view_acm.cpp ; exe doc_view_acm_deconstruct : doc_view_acm_deconstruct.cpp ; exe postconstructor_ex1 : postconstructor_ex1.cpp ; exe postconstructor_ex2 : postconstructor_ex2.cpp ; exe predestructor_example : predestructor_example.cpp ; exe signal_return_value : signal_return_value.cpp ; exe slot_arguments : slot_arguments.cpp ; --------------------------------------------------------------- -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

2 3

[signals2] lamda placeholder collision
by Michael Caisse 10 Mar '10

10 Mar '10

I am converting some older code to use signals2. The old source uses boost.lambda which results in a collision of placeholders from bind (included by signals2) and lambda. I converted to phoenix about a year ago and I'll fix this "problem" by moving the lambdas to phoenix ... but ... what is supposed to be the correct course of action for source wanting to use both signals2 and Boost.Lambda? Regards - michael -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

2 2

Soc: project idea
by Michele Caini 10 Mar '10

10 Mar '10

Hi all, what about extending GIL with a watermarking framework? I'm not an expert in using GIL, however if users are able to handle images via a generic way, I think it's possible (and quite easy) to develop an infrastructure of algorithms that manage images adding watermarks. Watermarking is a know problem, today. ;-) Michele

1 0

[inspect] More changes to Inspection Report
by Beman Dawes 09 Mar '10

09 Mar '10

More changes to the Inspection Report: * Line numbers are now shown when a problem is associated with a specific line in a file. * Apple macros clashes now show the specific name causing the problem. * Spacing is optimized so that problems without line numbers don't take up so much report space. See the results at http://boost.cowic.de/rc/inspect-trunk.html Thanks to everyone who commented yesterday! --Beman

6 6

enable_shared_from_this2
by Berserker 09 Mar '10

09 Mar '10

After experiencing some troubles with boost::python and enable_shared_from_this (as already reported in the past by someone to Peter Dimov), I started looking at the new (not documented) class enable_shared_from_this2. I made two changes in init_weak_once and now it seems to support shared_from_this in constructors and shared pointers "reinitialization". The original code (from boost 1.40): void init_weak_once() const { if( weak_this_._empty() ) { shared_this_.reset(static_cast< T* >( 0 ), detail::esft2_deleter_wrapper()); weak_this_ = shared_this_; } } The "patched" code: void init_weak_once() const { // Reinitialization support if( weak_this_.expired() ) { // shared_from_this in costructors support shared_this_.reset(static_cast <T*>(const_cast<enable_shared_from_this2>(this)), detail::esft2_deleter_wrapper()); weak_this_ = shared_this_; } } I know that the static_cast/const_cast is "problematic" on VC6 (and maybe other compilers) but it could be solved using an offset from enable_shared_from_this2 * to T *. I've attached a testcase that shows the problems with the current enable_shared_from_this2 implementation (with the proposed patch it works). Any feedback about this? struct null_deleter { template <typename T> inline void operator()(T *p) const { } }; class EnableThisPtrTester : public boost::enable_shared_from_this2<EnableThisPtrTester> { public: EnableThisPtrTester() { } EnableThisPtrTester(shared_ptr<EnableThisPtrTester> &ptr) { ptr = shared_from_this(); BOOST_CHECK(ptr); } }; BOOST_AUTO_TEST_CASE(test_enable_this_ptr) { { shared_ptr<EnableThisPtrTester> ptr1; shared_ptr<EnableThisPtrTester> ptr2(new EnableThisPtrTester(ptr1)); BOOST_CHECK(ptr1 == ptr2); BOOST_CHECK(ptr1.use_count() == ptr2.use_count()); BOOST_CHECK(ptr1->shared_from_this() == ptr1); BOOST_CHECK(ptr1->shared_from_this().use_count() == ptr1.use_count()); shared_ptr<EnableThisPtrTester> ptr3 = ptr2->shared_from_this(); BOOST_CHECK(ptr2 == ptr3); BOOST_CHECK(ptr2.use_count() == ptr3.use_count()); BOOST_CHECK(ptr1->shared_from_this().use_count() == ptr1.use_count()); } { shared_ptr<EnableThisPtrTester> ptr1; EnableThisPtrTester tester(ptr1); shared_ptr<EnableThisPtrTester> ptr2 = tester.shared_from_this(); BOOST_CHECK(ptr1 == ptr2); BOOST_CHECK(ptr1.use_count() == ptr2.use_count()); ptr1.reset(); ptr2.reset(); } { EnableThisPtrTester tester; { shared_ptr<EnableThisPtrTester> ptr1 = tester.shared_from_this(); shared_ptr<EnableThisPtrTester> ptr2 = tester.shared_from_this(); BOOST_CHECK(ptr1 == ptr2); BOOST_CHECK(ptr1.use_count() == ptr2.use_count()); shared_ptr<EnableThisPtrTester> ptr3(&tester, null_deleter()); BOOST_CHECK(ptr1 == ptr3); BOOST_CHECK(ptr1.use_count() == ptr3.use_count()); shared_ptr<EnableThisPtrTester> ptr4 = tester.shared_from_this(); BOOST_CHECK(ptr4 == ptr1); BOOST_CHECK(ptr4 == ptr3); BOOST_CHECK(ptr1.use_count() == ptr4.use_count()); BOOST_CHECK(ptr3.use_count() == ptr4.use_count()); } BOOST_CHECK(tester.shared_from_this()); } }

7 22

[SoC] C++0x Project Ideas
by Andrew Sutton 09 Mar '10

09 Mar '10

Previous years' SoC project ideas suggested porting some or all of a library to C++0x. I wanted to get a read on whether or not Boost developers think that there is value in these kinds of projects. I think there are some interesting pros and cons. One aspect of these projects that worries me about these kinds of projects is that they can force programmers to work in the netherworld between two major versions of the language. They may end up porting the libraries to a CPP abstraction layer rather than actually writing C++0x, which may artificially constrain the ported implementations. I would personally see students write native C++0x than trying to write something in between. Maybe not "porting" as much as "migrating". The obvious downside is that native C++0x ports may not be easily integrated into Boost. Thoughts? Andrew Sutton andrew.n.sutton(a)gmail.com

2 2

[la] [static size matrix/vector linear algebra library] More feedback
by Agustín K-ballo Bergé 09 Mar '10

09 Mar '10

A few more things I've noticed while using Boost.LA · boost/la/all.hpp conflicts with boost/assign/list_of.hpp if Boost.Assign is included first. I think this has to do with missing includes in a few headers. · Expressions like rotx_matrix() * roty_matrix() don't work. The temporaries have to be stored in proper matrix variables first. Apparently its result type does not model a valid matrix? (just guessing). · Could we have translation_matrix and scale_matrix, just as we have rot*_matrix ? · There is no (vector) normalize function. The implementation is straightforward. · During RangeEx review, the use of views and algorithms was widely discussed. It would be good for Boost.LA to follow the same conventions decided back then. IIRC, `m | transposed` was a lazy view and `transpose(m)` returned a new (eagerly) modified value. I should go back to the archives to confirm this was indeed the conclusion. · I would like to have X, Y, Z and W placeholders be convertible to the axis versor. However I don't think this can be actually implemented. Maybe something like versor<float,3>( X ) or unit_vector<float,3>( X ) would be better. Agustín K-ballo Bergé.- http://talesofcpp.blogspot.com

2 3

[program_options] validation_error in 1.42
by Alexander Fokin 09 Mar '10

09 Mar '10

It seems the way program_options deals with validation errors was changed in 1.42. Constructor of validation_error now takes kind_t and option name and value. Before 1.42 it was possible to specify what exactly was wrong with the option value in the constructor of validation_error. Now I see no options but to subclass validation_error. Was this change intentional? Also, documentation need to be fixed to reflect these changes. More precisely, the following line in "Custom Validators" section will lead to compilation error: > throw validation_error("invalid value"); -- Best regards, Alexander Fokin, ru.elric(a)gmail.com.

3 2

[utility/swap] MSVC 10 test failure, unsigned long to std::bitset conversion invalid?
by Niels Dekker - address until 2010-10-10 09 Mar '10

09 Mar '10

There's a regression failure of Microsoft Visual C++ 10 on a unit test of the boost::swap utility: > > ..\libs\utility\swap\test\std_bitset.cpp(20) : error C2440: > 'initializing' : cannot convert from 'unsigned long' to > 'std::bitset<_Bits>' > No constructor could take the source type, or constructor > overload resolution was ambiguous > > ..\libs\utility\swap\test\std_bitset.cpp(21) : error C2440 See http://www.boost.org/development/tests/trunk/developer/output/RWVC10-boost-… Do I understand correctly that MSVC 10 does not support implicit conversion from unsigned long to std::bitset<N>? The program "std_bitset.cpp" is at http://svn.boost.org/svn/boost/trunk/libs/utility/swap/test/std_bitset.cpp It does: #include <bitset> int test_main(int, char*[]) { typedef std::bitset<8> bitset_type; const bitset_type initial_value1 = 1ul; // Line 20. const bitset_type initial_value2 = 2ul; // Line 21. // [...] return 0; } Can anyone here reproduce the compile error? If so, would it be helpful to replace line 20 and 21 by using parentheses? As follows: const bitset_type initial_value1(1ul); const bitset_type initial_value2(2ul); Kind regards, Niels -- Niels Dekker http://www.xs4all.nl/~nd/dekkerware Scientific programmer at LKEB, Leiden University Medical Center

6 22

[range] strings
by Domagoj Saric 09 Mar '10

09 Mar '10

Currently, the following assertion: char const test_string[] = "a test string"; assert( test_string == boost::as_literal( test_string ) ); fails while the following one: assert( test_string == boost::as_literal( test_string ).advance_end( 1 ) ); passes because the left-hand side parameter of operator== is implicitly converted to a boost::iterator_range<> object which _includes_ the trailing zero (because it is treated as any other array) while the boost::iterator_range<> returned by boost::as_literal<>() _excludes_ the trailing zero... I 'know' that there is no 'happy' solution for this because the status quo is 'consistent' across all types but it, on the other hand, creates problems (or unexpected results), like the one outlined above, when strings, char pointers and literals are used...For this reason I would prefer more the other 'less than happy' solution that would treat strings in a special way (by never including the trailing zero)... Another problem is that the conversion, implict or otherwise, from a char container/range whose iterators are not plain char pointers (e.g. std::strings in 'secure STL' implementations) does not work (does not compile). My last post in the [program_options] thread offers a 'fix'. Yet another problem is that the as_literal<>() template function does not use the fact that it was passed an array to implicitly/directly deduce the length but it still calls std::strlen(). The make_range() function it calls for that: make_range( T* const r, bool ) { return iterator_range<T*>( r, r + length(r) ); } is also duplicated by: inline const char* str_end( const char* s, const char* ) { return s + strlen( s ); } ... Yes, some will object that the 'desired' direct deduction of length would be broken for 'typical' local buffers that are not completely filled (if there is no clear way of distinguishing them from literals): void foo() { char buf[ 256 ] = "a small string"; as_literal( buf ).size() == std::strlen( buf ); // in status quo as_literal( buf ).size() == _countof( buf ) - 1; // as proposed } but that could then also be said for the current implict conversion from such a "char buf[ 256 ]" into a boost::iterator_range<char const*>... I'd vote that this be handled with a runtime assertion that if a plain char array is passed it must be 'completely filled' (i.e. strlen( buf ) == _countof( buf ) ) otherwise the range must be explicitly constructed (iterator_range<char const *>( buf, buf + actual length )... Additionaly the above mentioned implementations of make_range() and str_end() add two extra instructions (substraction and addition) because they use strlen() that works with 'indexes'/size which then have to be converted to pointers... Additionaly#2 the boost::range_detail::is_char_ptr() function in as_literal.hpp is a runtime function when it seems it could be a metafunction... -- "What Huxley teaches is that in the age of advanced technology, spiritual devastation is more likely to come from an enemy with a smiling face than from one whose countenance exudes suspicion and hate." Neil Postman

2 4

Syntax colouring for Notepad++
by Paul A. Bristow 09 Mar '10

09 Mar '10

Does anyone have or know of a user defined language plugin for Notepad++ to provide syntax colouring for Quickbook and jamfiles (makefile is reasonable but not perfect)? (or suggestions for syntax colouring other text editors?) Thanks Paul --- Paul A. Bristow Prizet Farmhouse Kendal, UK LA8 8AB +44 1539 561830, mobile +44 7714330204 pbristow(a)hetp.u-net.com

4 3

[SoC] Submission Template
by Andrew Sutton 09 Mar '10

09 Mar '10

I've created a student submission template as part of the SoC application (which I'm currently working on). It's largely reconstructed from last year's template, with a couple of modifications. Can mentors from previous years and prospective mentors for this year please look over the template to see if there's any other information that might be useful? It can be found here: https://svn.boost.org/trac/boost/wiki/SoCSubmissionTemplate Thanks, Andrew Sutton andrew.n.sutton(a)gmail.com

3 3

Re: [boost] [contract] Released Contract Programming Library on SourceForge
by Andrzej Krzemienski 09 Mar '10

09 Mar '10

> I have released on SourceForge a library that implements Contract > Programming (a.k.a. Design by Contract(TM) ) for C++. I am considering > to submit this library to Boost (as Boost.Contract). > > Comments? Hi, As I already said, I am very glad that we can see a good Contract library for C++. I have not used it yet, but I base my first opinion on the documentation; the topics it mentions (sub-contracting, disabling contract checking within contract checks, the "oldof"), and references, proves that you have thoroughly investigated the subject. This is first such library for C++ that I am aware of. I am almost sure I will not use it in my work, in production code. I have trouble convincing my colleagues to use templates, as they are not used to "non-Java" syntax, and they find it suspicious. I am not sure how I would be able to convince anyone to writing: (class)(copyable)(myvector)(inherit)(pushable<T>)(public)(void)(push_back)( (const T&)(element) ) I am not even convinced myself. The IntelliSense will go mad. I understand the constraints you are under, but still... Perhaps if you do require this syntax, you should offer something more in exchange than only contract checking: hooks for IntelliSense, meta-data of contract-checked functions that the user can use like other type traits, etc... On the other hand, I believe the library is a very important step to introducing contract checking into C++ standard. Contracts were labeled as "No active interest today, but open to resubmit in future". Having gained a practical experience with C++ contracts, both implementability and usage, may be a good argument for reconsidering the proposal. C++ is so particular a language that the experience from Eiffel, which is mainly an OO language, usually would not apply; for instance, I could define equality as: bool operator==( MyType const& lhs, MyType const& rhs postcondition( result ) { result == !( lhs != rhs ); }; bool operator!= MyType const& lhs, MyType const& rhs ) postcondition( result ) { result == !( lhs == rhs ); }; or: bool operator==( MyType const& lhs, MyType const& rhs ); template< typename T > bool operator!=( T const& a, T const& b ) { return !(a == b); } // no post-condition required Which solution should I prefer? For an another example, if I am a defensive programmer, should I write: int compute_area() const postcondition( ans ) { ans > 0; }; or: unsigned int compute_area() const postcondition( ans ) { ans != 0; }; or: PositiveInteger compute_area() const; // compile-time checking - even better Similarly, for loop variants, I would be interested to know how it can or cannot or need not be used in more c++ specific loops: for( auto v : setOfValues ) { process(v); } How do I define a variant? Or is a variant needed? Perhaps the sole usage of "for each" guarantees termination? Or this one: std::ofsteam file("input.txt"); std::string text; while( file >> text ) { process(text); } Regards, &rzej

2 1

Re: [boost] [gil] External header files.
by Daniel James 09 Mar '10

09 Mar '10

On 1 March 2010 18:54, Enrique Nieloud <enieloud(a)gertrudisgraphics.com> wrote: > > I just wanted to report that the following two links are broken: > > boost/gil/extension/numeric/sampler.hpp > boost/gil/extension/numeric/resample.hpp > > > In the file: > http://www.boost.org/doc/libs/1_42_0/libs/gil/example/resize.cpp That's a pain. The html file is generated automatically from the source file, which states that it's including files that don't come with boost. It'd be better if they weren't expected to be in the boost file system. Daniel

4 4

[asio] Generating docs from trunk drops reference links
by Mateusz Loskot 09 Mar '10

09 Mar '10

Hi, I'm generating HTML docs for Boost.Asio from sources in SVN trunk (r60372) and I've noticed that all elements in Core -> Free Functions section of the Reference are not linked (Core, second column from left) So, all the links in this box point to HTML docs root directory file:///home/mloskot/dev/boost/_svn/trunk/libs/asio/doc/html/ However, the docs on website for Asio in Boost 1.42 does look correct: http://www.boost.org/doc/libs/1_42_0/doc/html/boost_asio/reference.html While generating, Boostbook (or Quickbook) does report this problem as follows: Error: no ID for constraint linkend: boost_asio.reference.read. Error: no ID for constraint linkend: boost_asio.reference.write. ... I'm generating the docs by executing sequence of two commands: mloskot@dog:~/dev/boost/_svn/trunk/libs/asio/doc$ perl doxy2qbk.pl mloskot@dog:~/dev/boost/_svn/trunk/libs/asio/doc$ bjam --v2 I attached boost-asio-docs-gen-log.txt.zip with .txt file which contains complete output of these two commands. I'm working on Linux Ubuntu 9.10 (64-bit) with the tools of versions: $ doxygen --version 1.6.1 $ bjam --version Boost.Build V2 (Milestone 12) Boost.Jam 03.1.18 $ quickbook --version Quickbook Version 1.5 Am I doing anything wrong or missing any step or Asio docs generator has changed after 1.42? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net Charter Member of OSGeo, http://osgeo.org

1 0

Re: [boost] [Review] ITL review starts today, February 18th
by Brian Wood 08 Mar '10

08 Mar '10

Joachim Faulhaber writes: >2010/3/7 Brian Wood <woodbrian77(a)gmail.com>: >> I was being blunt in order to let you know where I stand. >> I think the ITL is an interesting library and we may add >> marshalling support for it at some point. ? My suggestion >> is to not use the exact same class names in your library >> as are already used in the standard library. ? With the >> Boost::Intrusive library there is some of that as well. >> However, he has a class called ?rbtree that is an >> alternative to intrusive::(set and multiset). ?That rbtree >> class I support while for the time being I don't support >> the intrusive set or multiset. ? ?I'm not familiar enough >> with your library to know if an itl_rbtree class would be >> workable, but mention it just in case. > > Why not just support the class templates with the names that you like > and just ignoring the rest? I may do that. I was hoping to hear your thoughts on the itl_rbtree idea. Brian Wood http://webEbenezer.net (651) 251-9384

1 0

Boost.Atomic on OSX Leopard, x86-32?
by Josh Faust 08 Mar '10

08 Mar '10

Hey all, I'm having some trouble getting Boost.Atomic working properly on OSX Leopard. After wrangling compilation (all instances of "lock" -> "lock;", and "+r" -> "+q"), I'm hitting what looks like bad generated assembly. The following code, compiled with -O2: #include <boost/atomic.hpp> #include <stdio.h> using namespace boost; int main() { signed char a1, c1; char a2, c2; { atomic<char> a(41); char c = a++; a1 = a.load(); c1 = c; } { atomic<signed char> a(41); signed char c = a++; a2 = a.load(); c2 = c; } printf("%d %d\n", a1, c1); printf("%d %d\n", a2, c2); } produces: Macintosh-2:test josh$ ./simple2 42 41 93 41 Changing the first atomic to be the same type as the second (atomic<signed char>) produces the correct output (42 41 for both). This same problem shows up with int vs. unsigned int as well (have only tested those two). The assembly that produces the correct output: LCFI2: movl $1, %ecx ^^^^^^^^^^^^^^^^ Move 1 into ecx movl %esp, %ebp LCFI3: movl %ecx, %eax ^^^^^^^^^^^^^^^^ And eax subl $72, %esp LCFI4: movl %ebx, -12(%ebp) LCFI5: movl %esi, -8(%ebp) LCFI6: movl %edi, -4(%ebp) LCFI7: call L11 "L00000000001$pb": L11: popl %ebx movb $41, -25(%ebp) lock; xaddb %al, -25(%ebp) ^^^^^^^^^^^^^^^^^ first reference after assignment to eax (through al) movzbl -25(%ebp), %edx lock; addl $0, (%esp) movb $41, -25(%ebp) lock; xaddb %cl, -25(%ebp) ^^^^^^^^^^^^^^^^^ first reference after assignment to ecx (through cl) movl %ecx, %edi movzbl -25(%ebp), %ecx movb %cl, -41(%ebp) lock; addl $0, (%esp) The assembly that produces the incorrect output (when one is atomic<char> and the other is atomic<signed char>): movl $1, %eax ^^^^^^^^^^^^^^^^^ Move 1 into eax movl %esp, %ebp LCFI3: subl $72, %esp LCFI4: movl %ebx, -12(%ebp) LCFI5: movl %esi, -8(%ebp) LCFI6: movl %edi, -4(%ebp) LCFI7: call L11 "L00000000001$pb": L11: popl %ebx movb $41, -25(%ebp) lock; xaddb %al, -25(%ebp) ^^^^^^^^^^^^^^^^^^ First reference after assignment to eax (through al) movzbl -25(%ebp), %edx lock; addl $0, (%esp) movb $41, -25(%ebp) lock; xaddb %cl, -25(%ebp) ^^^^^^^^^^^^^^^^^^ First reference to ecx (through cl), but NO ASSIGNMENT. cl is garbage? movl %ecx, %edi movzbl -25(%ebp), %ecx movb %cl, -41(%ebp) lock; addl $0, (%esp) I am by no means an assembly expert (this has been a huge learning experience in fact) but this doesn't look right. I'm on: gcc version 4.0.1 (Apple Inc. build 5493) OSX 10.5.8, Intel Core 2 Duo (2.16 GHz) Just pulled a git clone of Boost.Atomic from http://git.chaoticmind.net/boost.atomic, rev. 886a675aa982ab5875c7bc98697b2eb26c134d03 (I think... I have no experience with git, just grabbed the top guid from "git log"). building without -O2 yields correct results. Anyone with more knowledge than I have any ideas? Am I being stupid and something else is wrong? Josh

2 4

Re: [boost] [Review] ITL review starts today, February 18th
by Brian Wood 08 Mar '10

08 Mar '10

Joachim Faulhaber writes: >2010/3/7 Brian Wood <woodbrian77(a)gmail.com>: >> Joachim Faulhaber writes: >> > >> If you stick >> with the names of some of the classes that you have today, >> at the very least, I'll put off developing marshalling support for >> the library. > >To give you a little feed back: The sentence above didn't exactly make >me feel in peace with you ;-/ But I'm open for your suggestions. I was being blunt in order to let you know where I stand. I think the ITL is an interesting library and we may add marshalling support for it at some point. My suggestion is to not use the exact same class names in your library as are already used in the standard library. With the Boost::Intrusive library there is some of that as well. However, he has a class called rbtree that is an alternative to intrusive::(set and multiset). That rbtree class I support while for the time being I don't support the intrusive set or multiset. I'm not familiar enough with your library to know if an itl_rbtree class would be workable, but mention it just in case. Regards, Brian Wood http://webEbenezer.net (651) 251-9384

2 1

Re: [boost] [Boost-users] [Review] ITL review starts today, February 18th
by Joachim Faulhaber 08 Mar '10

08 Mar '10

Hi Jeff, thank you for your review of the ITL. You have been supportive in the course of the development at different points giving feed back about shortcomings and helping with code patches and useful suggestions. I am glad to hear that you are actually using the library for real world applications already. 2010/3/8 Jeff Flinn <TriumphSprint2000(a)hotmail.com>: >> Please always state in your review, whether you think the library should >> be >> accepted as a Boost library. > > Yes, I think the library (with the interface improvements brought out during > the review) should be accepted into boost. I've already successfully used > the library with it's existing interface in a commercial product. > >> - What is your evaluation of the design? > > As brought up during the course of the review period my main concerns for > the library's interface are: > > 1) the bloated size of the interval class with it's dynamic bound data > member. This is being addressed by Joachim providing an interface to allow > use of static bound interval classes. > > 2) the fat interface on the interval class. In my view the myriad of > mutators would best be replaced with free functions in terms of the > interval's extents and return a interval passing the calculated extents to > an interval constructor which enforces the interval's invariant(s). There > should also be a method to construct an interval given unordered extents > that effectively does interval(min(arg1, arg2), max(arg1, arg2)). > > 3) better integration of std and user defined data types en lieu of itl's > specific types. Joachim has agreed to improvements in this area. I think we have agreed in the various points involved. > 4) I'd also like to see std::inserter "just work" with the containers. I discovered that it does not just work, because for std::insert_iterator there is an invariant involved that expects the inserted to be a non empty element of the container, that the element is inserted into. This invariant is broken with interval containers because an interval/segment is not an element of an interval container. > I shouldn't have to expect to look for the itl specific adder to do this. This > was the most common usage my applications had for populating interval > containers using std::copy/transform from my applications existing data > structures. > >> - What is your evaluation of the implementation? > > Seems adequate. I was able to port to the portions I needed to CodeWarrior > 9.4 (from 2003?). IIRC, Joachim integrated the changes(simplifications) that > allowed itl to work in this environment. I added all the changes suggested, but I remember that important parts of the code, itl global operators in particular, still did not compile with CW. I tried to set up CW myself, but encountered too many problems and gave up :( > Performance for the scale of problems I've been dealing with were fine, but > as has been discussed scaling to larger sizes of millions of items may > require some specialized containers. I don't see this as a problem, it's > analogous to std::map and std::unordered_map. I share this view. > Hmm, It just occurs to me that for my application I could void the N^2 size > issue of a split_interval_map<int, set<> > with a non_combining_map<int, > data> that allowed me to iterate through all items that overlap with an > arbitrary interval in and ordered fashion. That's not much different from a > std::map<interval, data>, but with some more interval specific wrapping of > the upper/lower_bound/equal_range methods. > >> - What is your evaluation of the documentation? > > I was able to get up and running fairly quickly. As discussed some of the > colorful terminology got in the way rather than helping. Also I had expected > to just be able to populate with std::inserter, and had trouble finding docs > related to this. The example for copy/transform helped, but even during this > review I have trouble finding the docs for itl::adder/inserter. True, escaped my notice. Has to be added. >> - What is your evaluation of the potential usefulness of the library? > > Very, I've come across needs for this capability in 3 different jobs in 3 > very different industries. I've had domain specific solutions and was > looking to create just such a generic library when Joachim submitted his > library. That's interesting. I had the basic ideas and first implementation in 1999 / 2000 and I had the immediate impression that it should be made available to the public domain. But due to other projects and commercial copyright of the first version, I did not have the opportunity to make it open source for years. I always thought someone else would be faster than me ;) >> - Did you try to use the library? With what compiler? Did you have any >> problems? > > Yes, the library is being used in a commercial application built with > CodeWarrior 9.4 on Mac/Windows and with VC8 and XCode 3.x. The library > required some modifications to the template declarations for CodeWarrior. Is it now fully or still only partially compilable with CW? >> - How much effort did you put into your evaluation? A glance? A quick >> reading? In-depth study? > > I read through the documentation, integrated the library with production > code, dug through compilation error messages and headers on CodeWarrior to > port a portion of the library. I've profiled code using itl to understand > performance implications. > >> - Are you knowledgeable about the problem domain? > > Yes, I've designed/implemented/optimized integral open-closed Interval and > IntervalSet classes for use in previous projects. Thanks again for your review and the support that you provided for the ITL library. Cheers, Joachim

1 0

[program_options]
by Thorsten Ottosen 08 Mar '10

08 Mar '10

Hi, I tried using bpo::options_description desc("Allowed options"); desc.add_options() (HELP, "produce help message"); but this fails to compile because HELP is an std::string. Isn't that a bit too restrictive? -Thorsten

9 14

is review system in place is extremely slow? (was Re: [rfc] rcpp)
by vicente.botet 08 Mar '10

08 Mar '10

Hi, ----- Original Message ----- From: "Mathias Gaunard" <mathias.gaunard(a)ens-lyon.org> To: <boost(a)lists.boost.org> Sent: Tuesday, February 23, 2010 12:47 PM Subject: Re: [boost] [rfc] rcpp > > Ivan Sorokin wrote: >> 3 When will Boost.Move become a part of boost? > > When it gets reviewed. > It could be said, however, that the review system in place is extremely > slow and that it's going to take years (literally). Why do you think the review system in place is extremely slow? Currently there are a lot of libraries to review, but no review managers. That means that the user community don't want to spend a little bit of their time to manage a review. In addition, the last review didn't had too much of reviewers (I'm also concerned by this point) I'm the review manager of Boost.Task but the library is not ready for review, because now Boost.Task depends on Boost.Move, Boost.Fiber and Boost.Atomic (which is not yet on the review queue). Maybe the review withards could add this on the schedule page. What do you propose to improve it? Best, _____________________ Vicente Juan Botet Escribá

32 87

Cooperative Multi-Tasking
by Daniel Larimer 08 Mar '10

08 Mar '10

I am curious whether anyone here has experience with any cross-platform cooperative multi-tasking libraries? I am familiar with the Boost.Coroutine library, but it only provides the "primitives" or "threads". What I am looking for is something much higher level that hides all of the coroutine details behind a asynchronous function call / future API. Something along the line of ASIO for coroutines. I am guessing that Boost.Asio would benefit from such a library. It seems obvious to me now that coroutines / cooperative multi-tasking is the superior approach to solving problems with a large number of actors and "locks" where heavy weight preemptive scheduling would bog down the system. Considering that cooperative multitasking is a very old concept, are there any reasons why there are no obvious libraries / scheduling systems in place? Does everyone "roll their own" or do they avoid it for some other reason? Dan

9 20

[Tokenmap] A (perfect) hash container library chcked-in to sandbox (RFC)
by Slawomir Lisznianski 08 Mar '10

08 Mar '10

http://svn.boost.org/svn/boost/sandbox/tokenmap/libs/tokenmap/doc/html/inde… A tokenmap is a data structure that uniquely maps pseudo-random generated keys with elements of the collection. Boost.Tokenmap is a (perfect) hash container library for C++. An important distinction between tokenmap and other dictionary-like containers, such as std::map or Boost.Unordered, is that tokenmap generates keys internally (referred to as "tokens") rather than relying on user to provide them. Specifically, when a new element is inserted into the tokenmap, an apparently random key is returned back to the caller which uniquely maps to the stored element. The returned key can later be used in a very efficient lookup. Although the code and documentation are far from complete, the implementation in the repo is functional and hopefully serves as a basis for further work. Slawomir

9 27

[Itl] Review
by Phil Endecott 08 Mar '10

08 Mar '10

My review of the proposed Interval Template Library follows. This is based only on studying the documentation, and previous discussion of the library on the Boost mailing list (e.g. http://lists.boost.org/Archives/boost/2009/03/149396.php ). Joachim has clearly put a lot of work into what is a substantial and well-documented library. Unfortunately, it seems to me that it is built on a weak foundation. One of the most well-known problems involving intervals is to determine which of a given set of intervals contains a particular point. How to store a set of intervals in such a way as to make this problem efficient has been extensively studied. If an "interval tree" (See e.g. Wikipedia: http://en.wikipedia.org/wiki/Interval_tree) is used, then the problem can be answered in logarithmic time and linear space. (More precisely: if there are N intervals in the container and M overlap the point of interest, finding them should take O(M + log N) time and the data structure should take O(N) space.) I was hoping to find that this library was an implementation of an interval tree. But it is not: it is built on top of normal standard-library containers. The implementation used can find the intervals that overlap a point in O(M + log N) time, but to do so it needs worst-case O(N^2) space and I think it needs O(N^2 log N) time to build that structure. Presumably this complexity is not an issue in Joachim's application. Unfortunately, library code will be used in many different applications including those where optimal complexity is required. For example, consider trying to store the lifespans of people in a genealogy program: recording a few thousand people living over a few hundred years would approach the worse-case space complexity and need megabytes of storage. Perhaps other reviewers will feel that there are sufficient applications where this library is suitable to justify its inclusion in Boost. My feeling is that since the interval tree data structure is so well known and its performance is so much better, we should not accept this library. Ideally it would be possible for Joachim to replace ITL's current standard containers with an interval tree implementation. Could an interval tree be implemented with an interval sufficiently similar to a std::set/map to make that possible, without losing the complexity benefits? Once again, I believe that apart from this weak foundation this looks like an excellent submission that is comprehensive and well-documented. Regards, Phil.

3 9

[Review] ITL review starts today, February 18th
by Hartmut Kaiser 07 Mar '10

07 Mar '10

Hi all, The formal review of the Interval Template Library (ITL) starts today, February 18th, 2010 and will end February 27th, 2010. ITL is being developed by Joachim Faulhaber. ------------------------------------------------ About the library: The Interval Template Library (ITL) is a library of interval containers that facilitates computations on collections of intervals and associated values. Use cases of such computations typically occur in the date and time problem domain, when collections of time intervals with associated data are analyzed, combined and aggregated. But the scope of applications for interval containers is more general and not limited to date and time problems. Interval containers allow to access and manipulate collections of intervals on an abstract level as sets and maps (of elements), but also to exploit segmental information that is given by the interval borders. Interval containers are fairly generic. They can be instantiated with discrete domain (or key) types like integral numeric types or boost::date or time types. But they also work with continuous domain types like double, rational or string. Using the latter allows to represent infinite sets and maps. The interface of the interval containers strives to be very intuitive and in line with the stl and other boost libraries. * The set theoretic operations union, difference, intersection and symmetric difference are available as operators for all interval containers and for many useful overloads between them. * There is iterator support on the level of segments and interval containers can be combined with stl containers of intervals via stl algorithms. * For discrete domain types, element iterators are available which makes interval sets and maps models of SortedAssociative Containers so they can be used with many stl algorithms. All interval containers are addable and subtractable. The addability and subtractability concept of the ITL leads to a general mechanism of aggregation on interval_maps which is called 'aggregate on overlap'. Exploiting 'aggregate on overlap' allows to compute many useful aggregation results in a simple and abstract manner. The ITL's Set and Map concepts are defined by a signature and collections of laws or axioms. Those semantical constraints have been validated using automatic law based tests. This gives the library both a well founded formal specification and an unusual thorough test base. The ITL emerged out of real world use cases and is successfully used at Cortex Software GmbH since a couple of years in the production code of various applications. On the boost developer's list it has been proposed in four previews and a review request since May 2008 and has been refactored and refined according to boost standards and suggestions from the list. The ITL is available from the boost vault: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=itl_3_2 _0.zip&directory=Containers Documentation is online available at: http://www.herold-faulhaber.de/boost_itl/doc/libs/itl/doc/html/index.html The current sources are in the sandbox: https://svn.boost.org/svn/boost/sandbox/itl/ ------------------------------------------------ Everybody on this list is invited to participate in this formal review. I hope to see your review of this library, including your vote, and I welcome your participation in the discussions on the Boost mailing list. Please always state in your review, whether you think the library should be accepted as a Boost library. Additionally, please consider giving feedback on the following general topics: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With what compiler? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? Regards Hartmut Review Manager --------------- Meet me at BoostCon www.boostcon.com

9 29

[Boost][Test] Small issue with explicit function initialization
by Sylvain Bougerel 07 Mar '10

07 Mar '10

Hi, I'm not sure if it's an issue or not. But I noticed that the given code does not compile: #define BOOST_TEST_MAIN #include <boost/test/included/unit_test.hpp> template <typename Tp1, typename Tp2> inline Tp2 stupid_cast (const Tp1& arg) { return static_cast<Tp2>(arg); } BOOST_AUTO_TEST_CASE( test_details_key ) { BOOST_CHECK(stupid_cast<float, int>(1.0) == 1); } It give the following error with g++ (GCC) 4.4.3: try.cpp:40:48: error: macro "BOOST_CHECK" passed 2 arguments, but takes just 1 try.cpp: In member function 'void test_details_key::test_method()': try.cpp:40: error: 'BOOST_CHECK' was not declared in this scope While the following does compile (and runs well): #define BOOST_TEST_MAIN #include <boost/test/included/unit_test.hpp> template <typename Tp1, typename Tp2> inline Tp2 stupid_cast (const Tp1& arg) { return static_cast<Tp2>(arg); } BOOST_AUTO_TEST_CASE( test_details_key ) { BOOST_CHECK((stupid_cast<float, int>(1.0) == 1)); // <----- I wrapped it in parenthesis } So I was wondering whether the BOOST_<level> macro (I did check that the others suffer the same problem) are expected to behave in this way, or they are just missing an extra layer of parenthesis around the arguments, or even GCC is at fault, or I'm missing something definitely... Regards, Sylvain

2 1

Re: [boost] [Review] ITL review starts today, February 18th
by Brian Wood 07 Mar '10

07 Mar '10

Joachim Faulhaber writes: > Let me put it this way: > std::set : could be model of itl::Set, if operators were implemented > itl::set : is model of itl::Set > itl::interval_set : is model of itl::Set but implemented via intervals > boost::dynamic_bitset : is almost model of itl::Set but implemented > via arrays of machine words. Joachim and I have previously discussed the names of some of the classes in his library in the context of serialization: *http://preview.tinyurl.com/y86phqg* I don't have plans yet to add support for this library to the C++ Middleware Writer, but I would suggest that you consider where you will be able to come up with serialization support for the library. I believe your options will be to add it yourself with Boost Serialization or go without it. If you stick with the names of some of the classes that you have today, at the very least, I'll put off developing marshalling support for the library. Brian Wood http://webEbenezer.net (651) 251-9384 "Then Samuel took a rock and set it up between Mizpah and Shen. He named it Ebenezer [Rock of Help] and said, 'Until now the L-RD has helped us.'"

2 1

[transact] Handling with user exceptions
by vicente.botet 07 Mar '10

07 Mar '10

Hi, I would like to initiate a discussion on how to manage with user exceptions. Here follows some thougth I'm implementing in Boost.STM. There are two main ways to manage with user exceptions: * exceptions commit transactions - corresponds to the current C++ behavior * exceptions abort on exit - corresponds to rollback The behavior associated to the curent language-like macros is to throw the catched exception. In this case, the exception shouldn't contain references to transaction specific objects. I was wondering if we cannot add a second family of macros that before a user exception leaves the transaction block the transaction is commited. BOOST_TRANSACT_A_ family will abort the transaction on user exception BOOST_TRANSACT_C_ family will commit the transaction on user exception This will allows to explore which both approaches, and see which approach is more usable, or if there is an approach that is better adapted to some particuler contexts. * Exceptions Commit Transactions - How to get this? While trying to commit on destruction we have catched any exception to release the commit_on_destruction variable. commit_on_destruction __comm( __txn ) ; t ry { i f ( false ) ; else / / to for ce a sentence / / t r a n s a c t i o n sentence } catch ( . . . ) { __comm. release ( ) ; throw ; } To make exception commit transactions by default, we should not release the committer. However, we need to avoid exception throw by commit when the transaction has been set as forced to abort or during unwinding exception. commit_on_destruction __comm( __txn ) ; t ry { <sentence > } catch ( . . . ) { i f ( __txn_.forced_to_abort ( ) ) __comm.release ( ) ; else __comm.commit ( ) ; throw ; } We need how to override the default behavior. If we have Exceptions Commit Transactions - we can abort the transaction in two ways: * Explicit try-block to Abort Transactions * Explicitly abort before throw - Explicit try-block to Abort Transactions The user may want the exception abort the transaction while leaving the transaction block. The user must explicitly state that this is the desired behavior by adding a try-catch block as shown below: BOOST_STM_C_TRANSACTION t ry { / / t r a n s a c t i o n block } catch (Ex&) { BOOST_STM_ABORT( ) ; throw ; } BOOST_STM_C_END_TRANSACTION; - Explicitly abort before throw The user may want the transaction to be aborted before throwing an exception. The user may explicitly state that this is the desired either by setting the current transaction as forced to abort, BOOST_STM_ABORT( ) ; throw except ( ) ; or by throwing the exception using the macro : / / . . . BOOST_STM_ABORT_AND_THROW( except ( ) ) ; / / . . . If we have Exceptions Abort on Exit we can commit the transaction as follows: - Explicit try-block to Commit Transactions The user must explicitly state that this is the desired behavior by adding a try-catch block as shown below: BOOST_STM_TRANSACTION t ry { / / t r a n s a c t i o n block } catch (Ex &ex ) { BOOST_STM_COMMIT( ) ; throw ; } BOOST_STM_END_TRANSACTION; boost::exception_ptr error; BOOST_STM_TRANSACTION t ry { / / t r a n s a c t i o n block } catch (Ex &) { error=boost::current_exception(); } BOOST_STM_END_TRANSACTION; if( error) boost::rethrow_exception(error); } Please let me know what do you think? Do you find this useful? Should we provide two families of macros? Best regards, _____________________ Vicente Juan Botet Escribá

2 6

[Review] The review of the ITL library ends today, March 7th
by Hartmut Kaiser 07 Mar '10

07 Mar '10

Hey all, The review of Joachim Faulhabers ITL library ends today, March 7th 2010. Please get your reviews in today or get in contact with me to agree on some offline schedule. Regards Hartmut Review Manager --------------- Meet me at BoostCon www.boostcon.com

1 0

Re: [boost] [transact] transaction language macros (was: Re: [transact] code in sandbox)
by vicente.botet 07 Mar '10

07 Mar '10

Hi, ----- Original Message ----- From: <strasser(a)uni-bremen.de> To: "vicente.botet" <vicente.botet(a)wanadoo.fr> Sent: Saturday, March 06, 2010 3:55 PM Subject: Re: [boost] [transact] transaction language macros (was: Re: [transact] code in sandbox) > > hi again, > > another thing, are you experienced with the various parsing libraries > of boost? No, I have made only some toy examples with Spirit long time ago. > I know that they're not capable of analyzing C++ code, but it seems to > me that the code transformation required for our little language > extension is fairly simple. > > boost has compliant preprocessor, so macros aren't a problem. > the most complicated thing would be to detect if a transaction is in a > user-loop or not, so the grammar would have to be able to read > for/while/... loops and correctly parse c++ scopes. > does anything like that already exist? To do something like that I will use LLVM that gives already this possibility. Of course starting to use LLVM will be not easy, but will open much more possibilities than a specific parsing. Best, Vicente

1 0

Re: [boost] [Boost-users] [Review] ITL review starts today, February 18th
by Joachim Faulhaber 06 Mar '10

06 Mar '10

Hi John, thank you for reviewing the ITL library! 2010/3/3 John Reid <j.reid(a)mail.cryst.bbk.ac.uk>: > Hartmut Kaiser wrote: >> >> The ITL is available from the boost vault: >> >> http://www.boostpro.com/vault/index.php?action=downloadfile&filename=itl_3_2 >> _0.zip&directory=Containers > > I have to say first I have been evaluating the version of ITL called > itl_plus_3_2_1 rather than the version in the boost vault. Perhaps someone > can tell me whether that is a big mistake or not. Using itl_plus_3_2_1 is completely ok. It is a later release than the review version itl_3_2_0. But the differences are marginal. Also itl_plus_3_2_1 contains more than the core library that is submitted for review. But you did not refer to these parts. So everything is fine. >> Please always state in your review, whether you think the library should >> be >> accepted as a Boost library. > > I think it should be accepted subject to the inclusion of an interval tree > implementation. > >> >> - What is your evaluation of the design? > > I suspect that making the open/closedness of an interval a template > parameter would suit more users although I don't have a strong opinion on > this one. There has been a discussion on this point already. http://permalink.gmane.org/gmane.comp.lib.boost.devel/199905 For continuous data types it seems like interval bounds are needed as data member. For intervals of integral types the bound_type can be a static property. I will adapt the design in this point. >> - What is your evaluation of the implementation? > > I would have liked to see interval trees in the implementation. For what > I've needed the library for so far this has not been a problem as most of > the intervals don't overlap. In the future I can see use cases where the > lack of interval trees would make the library impractical. I don't know how > much impact adding an interval tree implementation would have on the > existing interface. I think the current implementation has its value and application. It should not and can not completely be replaced by an implementation based on an interval_tree. This would improve certain use cases but lead to problems in others. I will report on this in more detail. An interval_tree based split_interval_map will be a valuable optimization that should be done as an additional class template. The current implementation is fully functional, correct, useful and efficient in most cases of application. >> - What is your evaluation of the documentation? > > Good. A tutorial would be a welcome addition. Some functions were > undocumented, I'm assuming they're documented in the review version. The "handcrafted" documentation relates to the major interface of overloaded functions and function templates. In order to keep that short, more specific functions are only documented in the part of the documentation that is generated from doxygen comments: http://www.joachim-faulhaber.de/boost_itl/doc/libs/itl/doc/html/interval_te… And yes, there may be few that have been forgotten. Please tell me, which ones you missed specifically. >> - What is your evaluation of the potential usefulness of the library? > > Very useful. It seems to have many applications in several different > domains. > >> - Did you try to use the library? With what compiler? Did you have any >> problems? > > I used gcc 4.4.1 and boost.python to make a python module for most of the > main elements of the library. I used this module successfully in an > application in genomics. However so far I have only had use for the > SplitIntervalMap so I have not used most of the library. > >> - How much effort did you put into your evaluation? A glance? A quick >> reading? In-depth study? > > A reasonable amount - enough to get up to speed and use the library. > >> - Are you knowledgeable about the problem domain? > > Not especially. > Thank you again. Best regards, Joachim

4 24

[BGL] Testing a graph for bipartiteness
by Matthias Walter 06 Mar '10

06 Mar '10

Hi, I'm working on a project where I need to determine whether a given graph is bipartite (possible yielding certificates for the two cases). As such a test can be perfectly implemented via BFS and visitor patterns, I wondered why there is no implementation in the BGL. Is there any reason or am I just to blind to find it? If I'm forced to write my own one, how about submitting it to BGL? best regards Matthias Walter

4 29

[numeric][ublas] trunk testing broken
by K. Noel Belcourt 06 Mar '10

06 Mar '10

Hi, Trunk testing broke with this commit: https://svn.boost.org/trac/boost/changeset/60156 Here's the error message. error: Unable to find file or target named error: 'test_coordinate_matrix_sort.cpp' error: referred from project at error: '../libs/numeric/ublas/test' Could someone please add this missing file or revert the commit? Thanks. -- Noel

3 3

[propertytree] Own storage
by Adam Badura 06 Mar '10

06 Mar '10

Are end users allowed to provide own parsers to populate property tree? For example for the (not yet available) Windows Registry? Or is this discouraged? If not then maybe adding a simple example to the documentation would be a good idea? Adam Badura

2 3

[log] init methods and named parameters
by Michael Caisse 05 Mar '10

05 Mar '10

I've gotten a head start looking at the boost.log library that will be reviewed in a couple weeks. The utility methods utilize boost.parameter's named parameters. For example, boost::log::init_log_to_file. I would like to decide at runtime (via a config file) which set of parameters will listed. For example, rotation_size or rotation_interval or both. It is my first real use of boost.parameter so I may be missing something that is common knowledge. I don't see an easy way to do this. I thought maybe building a fusion sequence of parameters or something like that was the way to go... Looking for guidance. Thanks. michael -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

3 8

filesystem utf-8 support?
by Jochen Wilhelmy 05 Mar '10

05 Mar '10

Hi! I wonder if boost::filesystem has support for utf-8. especially for windows this means that all path names have to be converted from utf-16 to utf-8 and back internally by boost::filesystem. for unix-like systems this may not be necessary as the locale can be set to utf-8 but auto-conversion for non-utf-8 locales would still be good. -Jochen

1 0

[boost.atomic] linker error with gcc 4.1.2
by Jamie Allsop 05 Mar '10

05 Mar '10

With gcc 4.1.2 (gcc 4.3.x is fine) I am seeing this linker error: .build/debug/working/SourceOne.o: In function `void boost::detail::atomic::platform_atomic_thread_fence<boost::memory_order>(boost::memory_order)': /thirdparty/boost/boost_1_42/boost/smart_ptr/detail/shared_count.hpp:229: multiple definition of `void boost::detail::atomic::platform_atomic_thread_fence<boost::memory_order>(boost::memory_order)' .build/debug/working/SourceTwo.o: /thirdparty/boost/boost_1_42/boost/atomic/detail/gcc-x86.hpp:63: first defined here Which doesn't make a lot of sense at first glance, but on closer inspection I see that: boost/atomic/detail/base.hpp defines platform_atomic_thread_fence as: template<typename T> static inline void platform_atomic_thread_fence(T order) { /* FIXME: this does not provide sequential consistency, need one global variable for that... */ platform_atomic<int> a; a.exchange(0, order); } and then it is defined as a specialisation in: boost/atomic/detail/gcc-x86.hpp as: template<> void platform_atomic_thread_fence(memory_order order) { switch(order) { case memory_order_seq_cst: full_fence(); case memory_order_acquire: case memory_order_consume: case memory_order_acq_rel: case memory_order_release: __asm__ __volatile__ ("" ::: "memory"); default:; } } Is this a compiler error or should the specialisation be declared as: template<> inline void platform_atomic_thread_fence(memory_order order) (which will work) Suggestions? Jamie

3 4

[type traits] add a set of templates to propagate const etc from one type to another?
by Vasilis Vasaitis 04 Mar '10

04 Mar '10

Hello, I've been looking at the Type Traits library recently, and it looks wonderful overall. However, it's lacking a use case that I end up needing quite often, so I thought I'd suggest it in case the authors and/or other users of the library find it useful. Allow me to explain. So Type Traits has the add_const / remove_const / is_const triplet (and similar for a few other type properties). add_const is great when you always know that you want to add the const, but sometimes you only want to do it conditionally to another type being const. So recently I've ended up using something like this from quite a few places in my code: template<class Source, class Target> struct propagate_const { typedef Target type; }; template<class Source, class Target> struct propagate_const<const Source, Target> { typedef const Target type; }; That is, propagate_const<Source, Target> will only add const to Target if Source is const too. What are the use cases for this? Well, for example recently I was writing an iterator class, and I wanted to avoid duplicating the code for the const_iterator case. Not a big deal, as it turned out, as I could just pass a const type as the template argument and have it behave as the const iterator. The only problem was that I was doing some pointer arithmetic with reinterpret_casts from T* to char* and back (where T is the template argument), so the compiler would complain if T was const. So instead of char I defined this: typedef typename propagate_const<T, char>::type char_type; Of course I could also have done this with a combination of is_const and add_const, but this would probably require more code than the propagate_const definition above. So what do people think? Would it be a useful addition alongside add_* and remove_*? Thanks, Vasilis P.S. Please CC me in your replies, as I've set the mailing lists to not send me emails (similar to not being subscribed). -- Vasilis Vasaitis "A man is well or woe as he thinks himself so."

10 18

command line parameters parser
by Denis Shevchenko 04 Mar '10

04 Mar '10

Hi! Sorry for my English, I am from Russia. Is there any interest in a library which parse command line parameters and call correspond functions/functors? Features: - check type of parameter, - check "value semantic" of parameter, - set necessity of parameter, - maybe set default value for parameter, - some other settings. Example: void help() { std::cout << "This is my help info!" << std::endl; ::exit( 0 ); // Exit after printing help info. } struct config_file { void operator()( const std::string& file ) { // Some work with obtaining file path. } }; void limit( const std::string& some_limit_value ) { // int limit = boost::lexical_cast< int >( some_limit_value ); // ... } int main( int argc, char* argv[] ) { typedef command_line_parameter_parser clp_parser; clp_parser parser; parser.add_parameter( "-h", "--help", help ); // Short and full names, in Unix tradition. // In this case we define parameter with one name and value (it is must be valid path); // Without check_value() obtaining path will not be checked. parser.add_parameter( "--config", config_file, clp_parser::with_value ).check_value( clp_parser::path ); parser.add_parameter( "-l", "--limit", limit ).check_type( clp_parser::integer ); // Is integer? parser.set_value_separator( ':' ); // "--config:/home/file.conf" instead default "--config=/home/file.conf" try { parser.parse( argc, argv ); } catch ( const std::exception& exc ) { std::cerr << exc.what() << std::endl; } ... return 0; } Denis

3 7

[1.39][preprocessor] "preprocessor/wstringize.hpp" not included by "preprocessor.hpp"
by Adam Badura 04 Mar '10

04 Mar '10

It seems that "preprocessor.hpp" includes (through "preprocessor/library.hpp") "preprocessor/stringize.hpp" but not "preprocessor/wstringize.hpp". I don't know whether this occurs in 1.42 as well but I guess it may. Adam Badura

1 0

boost::optional<A,B,...>
by Daniel Larimer 04 Mar '10

04 Mar '10

I have a situation where I have a class that stores two mutually exclusive optional values. This results in double overhead of two bools and twice the "reserved" space. I could opt for a boost::optional<boost::variant<A,B> >, but this would incur extra costs associated with the implementation of boost::variant. Considering the fact that boost::variant<> explicitly guarantees to be always "valid", it seems like it would be reasonable to have boost::optional<A,...> that behaves like boost::variant<>, yet is optimized specifically for allowing "empty" states as well. The boolean could then become the type index where 0 is empty, 1 is A, 2 is B etc. Thoughts? Dan

4 3

[rfc] rcpp
by Ivan Sorokin 04 Mar '10

04 Mar '10

Hello! I have a small library that is intended for convenient and declarative resource wrappers creation. Read Documentation: http://rain.ifmo.ru/~sorokin/rcpp/doc/index.html Main Page: http://rain.ifmo.ru/~sorokin/rcpp/ Although this library is small I think it is useful. I think it is possible to use it in implementations of asio, filesystem and thread. **-- Ivan Sorokin

6 16

Re: [boost] [mpl] Basic mpl sequence question
by Martim Nascimento 04 Mar '10

04 Mar '10

Maybe you forget to add the mpl::find include. #include<boost/mpl/vector.hpp> //here #include <boost/mpl/find.hpp> using namespace boost; typedef mpl::vector<char,short,int,long,float,double> types; typedef mpl::find<types,long>::type long_pos; int main() { }

1 0

Another implementation of properties.
by Germán Diago 04 Mar '10

04 Mar '10

Hello. I've been trying to implement properties for c++0x, for now. I've come up with this solution for now. You need g++ svn to test it. It's a partial implementation, since not every operator is overloaded. Space overhead: - one pointer to the object per property instance. - the pointer to the member functions is shared among every instance of the class, so it's a per-class and not per-instance overhead, which is negligible. Usage: class Person { int getAge() const { .... }; void setAge(int age) { ... }; PROPS_RWPROPERTY(Age); Person() : Age(this) {} }; You can: - declare getters/setters const or nonconst. - getters must have one parameter. - setters must return void. - it has some operators overloaded, but the idea is to overload all of them if the implementation is all right. - the property returns whatever you put in your getter and gets as a parameter what you put in the setter. If you declare the getters and setters to be VIRTUAL, you get virtual behaviour, so you can use virtual properties, even with pure virtual functions, and it will work. Caveats: - Needs c++0x compiler for now. - Not enforced the read-only access for properties for now. I need extended friend declarations for that, and the operator= would be made private with friend class. But for now it's not reinforced. I think this implementation is pretty usable as-is. It's just a matter of extending it. I don't use the offset trick because I think it does not work with classes with virtual members, but I'm not sure. The implementation contains Trivial properties as well, which for now, are the same as fields I think. Implementation: #include <functional> #include <type_traits> #include <iostream> #ifndef _PROPS_PROPERTY_HPP_ #define _PROPS_PROPERTY_HPP_ namespace props { template <class GetterAddress, class SetterAddress> class RWProperty; template <class GetterAddress, class SetterAddress> class ROProperty; template <class PropType> class TROProperty; template <class PropType> class TRWProperty; namespace detail { struct unused {}; template <bool cond, class T = void> struct EnableIf { typedef T type; }; template <class T> struct EnableIf<false, T> {}; template <bool cond, class T = void> struct DisableIf {}; template <class T> struct DisableIf<false, T> { typedef T type; }; template <class ObjectType, class Ret, Ret (ObjectType::*Getter)()> struct WrapperGetter { typedef ObjectType object_t; typedef Ret result_type; Ret (ObjectType::*getter)(); WrapperGetter() : getter(Getter) {} }; template <class ObjectType, class Ret, Ret (ObjectType::*Getter)() const> struct WrapperGetterConst { typedef ObjectType object_t; typedef Ret result_type; Ret (ObjectType::*getter)() const; WrapperGetterConst() : getter(Getter) {} }; template <class ObjectType, class Arg, void (ObjectType::*Setter)(Arg)> struct WrapperSetter { typedef ObjectType object_t; typedef void result_type; typedef Arg argument_type; void (ObjectType::*setter)(Arg); WrapperSetter() : setter(Setter) {} }; template <class ObjectType, class Arg, void (ObjectType::*Setter)(Arg) const> struct WrapperSetterConst { typedef ObjectType object_t; typedef void result_type; typedef Arg argument_type; void (ObjectType::*setter)(Arg) const; WrapperSetterConst() : setter(Setter) {} }; template <class T> struct IsProperty : public std::false_type {}; template <class GetterAddress, class SetterAddress> struct IsProperty<RWProperty<GetterAddress, SetterAddress> > : public std::true_type {}; template <class GetterAddress, class SetterAddress> struct IsProperty<ROProperty<GetterAddress, SetterAddress> > : public std::true_type {}; template <class PropType> struct IsProperty<TRWProperty<PropType> > : public std::true_type {}; template <class PropType> struct IsProperty<TROProperty<PropType> > : public std::true_type {}; template <class T> struct IsConstMemberGetter : public std::false_type {}; template <class Ret, class Object> struct IsConstMemberGetter<Ret (Object::*)() const> : public std::true_type {}; template <class T> struct IsConstMemberSetter : public std::false_type {}; template <class ObjectType, class Arg> struct IsConstMemberSetter<void (ObjectType::*)(Arg) const> : public std::true_type {}; template <class ObjectType, class Ret, Ret (ObjectType::*Getter)()> WrapperGetter<ObjectType, Ret, Getter> deduceWrapperForGetter(); template <class ObjectType, class Ret, Ret (ObjectType::*Getter)() const> WrapperGetterConst<ObjectType, Ret, Getter> deduceWrapperForGetter(); template <class ObjectType, class Arg, void (ObjectType::*Setter)(Arg)> WrapperSetter<ObjectType, Arg, Setter> deduceWrapperForSetter(); template <class ObjectType, class Arg, void (ObjectType::*Setter)(Arg) const> WrapperSetterConst<ObjectType, Arg, Setter> deduceWrapperForSetter(); template <class ObjectType, class Arg> Arg deduceSetterArg(void (ObjectType::*Setter)(Arg) const); template <class ObjectType, class Arg> Arg deduceSetterArg(void (ObjectType::*Setter)(Arg)); template <class ObjectType, class PropType> auto deduceGetterRet(PropType (ObjectType::*Getter)() const, const ObjectType * obj = 0) -> typename EnableIf<IsConstMemberGetter<PropType (ObjectType::*)() const>::value, decltype((obj->*Getter)())>::type; template <class ObjectType, class PropType> auto deduceGetterRet(PropType (ObjectType::*Getter)(), ObjectType * obj = 0) -> typename EnableIf<!IsConstMemberGetter<PropType (ObjectType::*)()>::value, decltype((obj->*Getter)()) >::type; } //namespace detail template <class PropType> class TRWProperty { static_assert(!std::is_reference<PropType>::value, "Property types must not be reference types"); PropType value_; public: typedef typename std::remove_cv<PropType>::type value_type; typedef PropType & GetterReturnType; typedef const PropType & ConstGetterReturnType; /************************Constructors*************************************/ ///Default constructor TRWProperty() = default; ///Construct from other property (rvalue) template <class OtherProp> TRWProperty(OtherProp && other, typename detail::EnableIf<detail::IsProperty<OtherProp>::value>::type * = 0) : value_(std::move(other())) {} ///Construct from other value (rvalue) template <class PropVal> TRWProperty(PropVal && val, typename detail::EnableIf<!detail::IsProperty<PropVal>::value>::type * = 0) : value_(std::move(val)) {} ///Construct from other value (lvalue) template <class PropVal> TRWProperty(const PropVal & value, typename detail::EnableIf<!detail::IsProperty<PropVal>::value>::type * = 0) : value_(value) {} ///Construct from other property (lvalue) template <class OtherProp> TRWProperty(const OtherProp & prop, typename detail::EnableIf<detail::IsProperty<OtherProp>::value>::type * = 0) : value_(prop()) {} //***************************Assignment operators*****************************/ ///Assign from other property (rvalue) template <class OtherProp> typename detail::EnableIf<detail::IsProperty<OtherProp>::value, TRWProperty &>::type operator=(OtherProp && other) { value_ = std::move(other()); return *this; } ///Assign from other value (rvalue) template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, TRWProperty &>::type operator=(PropValue && val) { value_ = std::move(val); return *this; } ///Assign from other property (lvalue) template <class OtherProp> typename detail::EnableIf<detail::IsProperty<OtherProp>::value, TRWProperty &>::type operator=(const OtherProp & other) { value_ = other(); return *this; } ///Assign from other value (lvalue) template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, TRWProperty &>::type operator=(const PropValue & val) { value_ = val; return *this; } /***************************Obtain value operators*****************************/ ConstGetterReturnType operator()() const { return value_; } GetterReturnType operator()() { return value_; } /****************************Implicit conversions******************************/ operator ConstGetterReturnType() const { return value_; } operator GetterReturnType() { return value_; } /******************************Arithmetic Operators**********************************/ template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, TRWProperty&>::type operator+=(const Prop & other) { (*this)() += other(); return *this; } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, TRWProperty&>::type operator+=(const PropValue & value) { (*this)() += value; return *this; } TRWProperty & operator++() { ++((*this)()); return *this; } TRWProperty & operator++(int) { ((*this)())++; return *this; } TRWProperty & operator--() { --((*this)()); return *this; } TRWProperty & operator--(int) { ((*this)())--; return *this; } /*****************************Relational operators**************************************/ template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, bool>::type operator<(const Prop & other) const { return (*this)() < other(); } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, bool>::type operator<(const PropValue & value) const { return (*this)() < value; } template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, bool>::type operator==(const Prop & other) const { return (*this)() == other(); } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, bool>::type operator==(const PropValue & value) const { return (*this)() == value; } //******************************Swap*************************** template <class OtherProp> void swap(OtherProp & other) { TRWProperty tmp(std::move(other)); other = std::move(*this); *this = std::move(tmp); } }; template <class PropType> class TROProperty { //FIXME: Make private operator= and friend class the class containing the property static_assert(!std::is_reference<PropType>::value, "Property types must not be reference types"); PropType value_; public: typedef typename std::remove_cv<PropType>::type value_type; typedef PropType & GetterReturnType; typedef const PropType & ConstGetterReturnType; /************************Constructors*************************************/ ///Default constructor TROProperty() = default; ///Construct from other property (rvalue) template <class OtherProp> TROProperty(OtherProp && other, typename detail::EnableIf<detail::IsProperty<OtherProp>::value>::type * = 0) : value_(std::move(other())) {} ///Construct from other value (rvalue) template <class PropVal> TROProperty(PropVal && val, typename detail::EnableIf<!detail::IsProperty<PropVal>::value>::type * = 0) : value_(std::move(val)) {} ///Construct from other value (lvalue) template <class PropVal> TROProperty(const PropVal & value, typename detail::EnableIf<!detail::IsProperty<PropVal>::value>::type * = 0) : value_(value) {} ///Construct from other property (lvalue) template <class OtherProp> TROProperty(const OtherProp & prop, typename detail::EnableIf<detail::IsProperty<OtherProp>::value>::type * = 0) : value_(prop()) {} //***************************Assignment operators*****************************/ ///Assign from other property (rvalue) template <class OtherProp> typename detail::EnableIf<detail::IsProperty<OtherProp>::value, TROProperty &>::type operator=(OtherProp && other) { value_ = std::move(other()); return *this; } ///Assign from other value (rvalue) template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, TROProperty &>::type operator=(PropValue && val) { value_ = std::move(val); return *this; } ///Assign from other property (lvalue) template <class OtherProp> typename detail::EnableIf<detail::IsProperty<OtherProp>::value, TROProperty &>::type operator=(const OtherProp & other) { value_ = other(); return *this; } ///Assign from other value (lvalue) template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, TROProperty &>::type operator=(const PropValue & val) { value_ = val; return *this; } /***************************Obtain value operators*****************************/ ConstGetterReturnType operator()() const { return value_; } GetterReturnType operator()() { return value_; } /****************************Implicit conversions******************************/ operator ConstGetterReturnType() const { return value_; } operator GetterReturnType() { return value_; } /******************************Arithmetic Operators**********************************/ template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, TROProperty&>::type operator+=(const Prop & other) { (*this)() += other(); return *this; } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, TROProperty&>::type operator+=(const PropValue & value) { (*this)() += value; return *this; } TROProperty & operator++() { ++((*this)()); return *this; } TROProperty & operator++(int) { ((*this)())++; return *this; } TROProperty & operator--() { --((*this)()); return *this; } TROProperty & operator--(int) { ((*this)())--; return *this; } /*****************************Relational operators**************************************/ template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, bool>::type operator<(const Prop & other) const { return (*this)() < other(); } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, bool>::type operator<(const PropValue & value) const { return (*this)() < value; } template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, bool>::type operator==(const Prop & other) const { return (*this)() == other(); } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, bool>::type operator==(const PropValue & value) const { return (*this)() == value; } //******************************Swap*************************** template <class OtherProp> void swap(OtherProp & other) { TROProperty tmp(std::move(other)); other = std::move(*this); *this = std::move(tmp); } }; //***********************************************Elaborated properties******************************************* template <class GetterAddress, class SetterAddress> class RWProperty { typedef typename GetterAddress::object_t ObjectType; ObjectType * object_; static SetterAddress setter_; static GetterAddress getter_; typedef decltype((object_->*GetterAddress::getter)()) GetterReturnType; typedef const decltype((object_->*GetterAddress::getter)()) ConstGetterReturnType; typedef typename std::remove_cv<GetterReturnType>::type value_type; public: //Constructor without value RWProperty(ObjectType * object) : object_(object) { } //Constructor with value (lvalue) template <class PropValue> RWProperty(ObjectType * object, const PropValue & val, typename detail::EnableIf<!detail::IsProperty<PropValue>::value>::type * = 0) : object_(object) { (object_->*setter_.setter)(val); } //Constructor with other property (lvalue) template <class OtherProp> RWProperty(ObjectType * object, const OtherProp & other, typename detail::EnableIf<detail::IsProperty<OtherProp>::value>::type * = 0) : object_(object) { (object_->*setter_.setter)(other()); } //Constructor with value (rvalue) template <class PropValue> RWProperty(ObjectType * object, PropValue && val, typename detail::EnableIf<!detail::IsProperty<PropValue>::value>::type * = 0) : object_(object) { (object_->*setter_.setter)(std::move(val)); } //Constructor with other property (rvalue) template <class OtherProp> RWProperty(ObjectType * object, OtherProp && other, typename detail::EnableIf<detail::IsProperty<OtherProp>::value>::type * = 0) : object_(object) { (object_->*setter_.setter)(std::move(other())); } ConstGetterReturnType operator()() const { return (object_->*getter_.getter)(); } GetterReturnType operator()() { return (object_->*getter_.getter)(); } operator ConstGetterReturnType() const { (object_->*getter_.getter)(); } operator GetterReturnType() { return (object_->*getter_.getter)(); } ///Assign from other property (rvalue) template <class OtherProp> typename detail::EnableIf<detail::IsProperty<OtherProp>::value, RWProperty &>::type operator=(OtherProp && other) { (object_->*setter_.setter)(std::move(other())); return *this; } ///Assign from other value (rvalue) template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, RWProperty &>::type operator=(PropValue && val) { (object_->*setter_.setter)(std::move(val)); return *this; } ///Assign from other property (lvalue) template <class OtherProp> typename detail::EnableIf<detail::IsProperty<OtherProp>::value, RWProperty &>::type operator=(const OtherProp & other) { (object_->*setter_.setter)(other()); return *this; } ///Assign from other value (lvalue) template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, RWProperty &>::type operator=(const PropValue & val) { (object_->*setter_.setter)(val); return *this; } /******************************Arithmetic Operators**********************************/ template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, RWProperty&>::type operator+=(const Prop & other) { auto res = (*this)() + other(); (object_->*setter_.setter)(res); return *this; } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, RWProperty&>::type operator+=(const PropValue & value) { auto res = (*this)() + value; (object_->*setter_.setter)(res); return *this; } RWProperty & operator++() { auto val = (*this)() + 1; (object_->*setter_.setter)(val); return *this; } RWProperty & operator++(int) { ++(*this); return *this; } RWProperty & operator--() { auto val = (*this)() - 1; (object_->*setter_.setter)(val); return *this; } RWProperty & operator--(int) { --(*this); return *this; } /*****************************Relational operators**************************************/ template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, bool>::type operator<(const Prop & other) const { return (*this)() < other(); } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, bool>::type operator<(const PropValue & value) const { return (*this)() < value; } template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, bool>::type operator==(const Prop & other) const { return (*this)() == other(); } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, bool>::type operator==(const PropValue & value) const { return (*this)() == value; } //******************************Swap*************************** template <class OtherProp> void swap(OtherProp & other) { value_type tmp(std::move(other())); other = std::move(*this); *this = std::move(tmp); } }; template <class GetterAddress, class SetterAddress> GetterAddress RWProperty<GetterAddress, SetterAddress>::getter_; template <class GetterAddress, class SetterAddress> SetterAddress RWProperty<GetterAddress, SetterAddress>::setter_; //***********************************************Elaborated properties******************************************* template <class GetterAddress, class SetterAddress> class ROProperty { typedef typename GetterAddress::object_t ObjectType; ObjectType * object_; static SetterAddress setter_; static GetterAddress getter_; typedef decltype((object_->*GetterAddress::getter)()) GetterReturnType; typedef const decltype((object_->*GetterAddress::getter)()) ConstGetterReturnType; typedef typename std::remove_cv<GetterReturnType>::type value_type; public: //Constructor without value ROProperty(ObjectType * object) : object_(object) { } //Constructor with value (lvalue) template <class PropValue> ROProperty(ObjectType * object, const PropValue & val, typename detail::EnableIf<!detail::IsProperty<PropValue>::value>::type * = 0) : object_(object) { (object_->*setter_.setter)(val); } //Constructor with other property (lvalue) template <class OtherProp> ROProperty(ObjectType * object, const OtherProp & other, typename detail::EnableIf<detail::IsProperty<OtherProp>::value>::type * = 0) : object_(object) { (object_->*setter_.setter)(other()); } //Constructor with value (rvalue) template <class PropValue> ROProperty(ObjectType * object, PropValue && val, typename detail::EnableIf<!detail::IsProperty<PropValue>::value>::type * = 0) : object_(object) { (object_->*setter_.setter)(std::move(val)); } //Constructor with other property (rvalue) template <class OtherProp> ROProperty(ObjectType * object, OtherProp && other, typename detail::EnableIf<detail::IsProperty<OtherProp>::value>::type * = 0) : object_(object) { (object_->*setter_.setter)(std::move(other())); } ConstGetterReturnType operator()() const { return (object_->*getter_.getter)(); } GetterReturnType operator()() { return (object_->*getter_.getter)(); } operator ConstGetterReturnType() const { (object_->*getter_.getter)(); } operator GetterReturnType() { return (object_->*getter_.getter)(); } ///Assign from other property (rvalue) template <class OtherProp> typename detail::EnableIf<detail::IsProperty<OtherProp>::value, ROProperty &>::type operator=(OtherProp && other) { (object_->*setter_.setter)(std::move(other())); return *this; } ///Assign from other value (rvalue) template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, ROProperty &>::type operator=(PropValue && val) { (object_->*setter_.setter)(std::move(val)); return *this; } ///Assign from other property (lvalue) template <class OtherProp> typename detail::EnableIf<detail::IsProperty<OtherProp>::value, ROProperty &>::type operator=(const OtherProp & other) { (object_->*setter_.setter)(other()); return *this; } ///Assign from other value (lvalue) template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, ROProperty &>::type operator=(const PropValue & val) { (object_->*setter_.setter)(val); return *this; } /******************************Arithmetic Operators**********************************/ template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, ROProperty&>::type operator+=(const Prop & other) { auto res = (*this)() + other(); (object_->*setter_.setter)(res); return *this; } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, ROProperty&>::type operator+=(const PropValue & value) { auto res = (*this)() + value; (object_->*setter_.setter)(res); return *this; } ROProperty & operator++() { auto val = (*this)() + 1; (object_->*setter_.setter)(val); return *this; } ROProperty & operator++(int) { ++(*this); return *this; } ROProperty & operator--() { auto val = (*this)() - 1; (object_->*setter_.setter)(val); return *this; } ROProperty & operator--(int) { --(*this); return *this; } /*****************************Relational operators**************************************/ template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, bool>::type operator<(const Prop & other) const { return (*this)() < other(); } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, bool>::type operator<(const PropValue & value) const { return (*this)() < value; } template <class Prop> typename detail::EnableIf<detail::IsProperty<Prop>::value, bool>::type operator==(const Prop & other) const { return (*this)() == other(); } template <class PropValue> typename detail::EnableIf<!detail::IsProperty<PropValue>::value, bool>::type operator==(const PropValue & value) const { return (*this)() == value; } //******************************Swap*************************** template <class OtherProp> void swap(OtherProp & other) { value_type tmp(std::move(other())); other = std::move(*this); *this = std::move(tmp); } }; template <class GetterAddress, class SetterAddress> GetterAddress ROProperty<GetterAddress, SetterAddress>::getter_; template <class GetterAddress, class SetterAddress> SetterAddress ROProperty<GetterAddress, SetterAddress>::setter_; } //namespace props #define PROPS_RWPROPERTY(propname) \ ::props::RWProperty< \ decltype(::props::detail::deduceWrapperForGetter<ClassName, \ decltype(::props::detail::deduceGetterRet(&ClassName::get##propname)), \ &ClassName::get##propname>()), \ decltype(::props::detail::deduceWrapperForSetter<ClassName, \ decltype(::props::detail::deduceSetterArg(&ClassName::set##propname)), \ &ClassName::set##propname>())> propname #define PROPS_ROPROPERTY(propname) \ ::props::ROProperty< \ decltype(::props::detail::deduceWrapperForGetter<ClassName, \ decltype(::props::detail::deduceGetterRet(&ClassName::get##propname)), \ &ClassName::get##propname>()), \ decltype(::props::detail::deduceWrapperForSetter<ClassName, \ decltype(::props::detail::deduceSetterArg(&ClassName::set##propname)), \ &ClassName::set##propname>())> propname #endif

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[mpl] Basic mpl sequence question
by Michael Robinson 04 Mar '10

04 Mar '10

Hi, I'm a newbie with mpl and I'm trying to execute some example code from the book "C++ Template Metaprogramming", by Abrahams and Gurtovoy: >From section 5.2, p. 78, Sequences and Algorithms: I wrote this code: // // mpltest.C // #include<boost/mpl/vector.hpp> using namespace boost; typedef mpl::vector<char,short,int,long,float,double> types; typedef mpl::find<types,long>::type long_pos; int main() { } And I get this compiler error on the mpl::find line: $ g++ mpltest.C -ompltest mpltest.C:10: error: expected initializer before ‘<’ token Can you tell me what I'm doing wrong? Thank you, Mike FYI/IYC: $ g++ --version g++ (GCC) 4.4.1 20090725 (Red Hat 4.4.1-2) Copyright (C) 2009 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ____________________________________________________________ Get Free Email with Video Mail & Video Chat! http://www.netzero.net/freeemail?refcd=NZTAGOUT1FREM0210

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[Filesystem V3] Filesystem Version 3 beta 1 available for download and comment
by Beman Dawes 03 Mar '10

03 Mar '10

The first beta release of Boost.Filesystem Version 3 is now available. The documentation can be viewed at http://mysite.verizon.net/beman/v3/index.htm Important differences from the prior version: http://mysite.verizon.net/beman/v3/v3.html The beta can be downloaded from the Boost vault. See http://www.boostpro.com/vault/index.php?&direction=0&order=&directory=Files… Installing the beta is described at http://mysite.verizon.net/beman/v3/install_distro.html I'm concerned about breaking existing code. While some workarounds have been provided already, I'd open to further suggestions as to how to mitigate code breakage. The tentative plan for integrating V3 into the boost release cycle involves several steps: * For the first boost release cycle, ship V2 as the default, but V3 is present and can be activated by users. * For an additional boost release cycle, ship V3 as the default, but V2 is present (but deprecated) and can be activated by users. * For the following boost release cycle, V2 is removed and no longer supported. The plan is to go through as many beta cycles as needed to reach stability. Although quite a bit of testing has already been done, this is definitely beta software that isn't ready yet for production use. Any comments appreciated. --Beman

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[range] resulting range type
by Andrey Torba 03 Mar '10

03 Mar '10

Hi All, When i implement range based algorithms i always have to write `boost::iterator_range<typename boost::range_iterator<R>::type>'. It is pretty annoying. i.e.: template<class R> boost::iterator_range<typename boost::range_iterator<R>::type> Algo(R& r); I would like to have special metafunction in Boost.Range for such cases to make code more cleaner: template<class R> typename boost::make_range<R>::type Algo(R& r); What do you think? -- Regards, Andrey

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[graph] gcc 3.4 & 4.0 currently broken
by Ralf W. Grosse-Kunstleve 03 Mar '10

03 Mar '10

boost svn trunk rev 60079 broke our gcc 3.4 and 4.0 builds (various platforms). The problem is line 52 in boost/graph/two_bit_color_map.hpp BOOST_STATIC_ASSERT(elements_per_char > 0); It fails with (gcc 3.4 in this case): % g++ -o boost/libs/python/src/object/inheritance.o -c -DBOOST_PYTHON_MAX_BASES=2 -DBOOST_PYTHON_SOURCE -DBOOST_PYTHON_BOOL_INT_STRICT -fPIC -fno-strict-aliasing -w -DNDEBUG -O3 -ffast-math -ftrapping-math -DBOOST_ALL_NO_LIB -DBOOST_DISABLE_THREADS -I/net/chevy/raid1/rwgk/hot/boost -I/usr/include/python2.3 /net/chevy/raid1/rwgk/hot/boost/libs/python/src/object/inheritance.cpp In file included from /net/chevy/raid1/rwgk/hot/boost/boost/graph/breadth_first_search.hpp:26, from /net/chevy/raid1/rwgk/hot/boost/libs/python/src/object/inheritance.cpp:7: /net/chevy/raid1/rwgk/hot/boost/boost/graph/two_bit_color_map.hpp:52: error: non-constant `(((int)boost::two_bit_color_map<IndexMap>::elements_per_char) > 0)' cannot be used as template argument /net/chevy/raid1/rwgk/hot/boost/boost/graph/two_bit_color_map.hpp:52: error: `value' is not a member of `<declaration error>' Commenting out line 52 resolves the error. I printed the value of elements_per_char and it appears to be correct (4). There is no problem with gcc 3.2 and gcc 4.1 through 4.4. Maybe a BOOST_WORKAROUND to disable the static assert for 3.4 and 4.0? Ralf

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[uuid] basic_random_generator doesn't produce a fully randomized uuid when sizeof(unsigned long) == 4
by Sylvester-Bradley, Gareth 03 Mar '10

03 Mar '10

Hi Andy, I wonder if the following is a flaw in basic_random_generator<> (boost/uuid/uuid_generators.hpp, line 366-374)? On many platforms sizeof(unsigned long) == 4. This means that the first 8 bytes of the uuid are populated with random data, but in my tests the remaining 8 bytes are populated with repeated data, and then only by relying on the undefined behaviour of >> when its "right operand is greater than or equal to the length in bits of the promoted left operand." For example, try the following test program with a Win32 build by Visual C++ 9.0 - #include <iostreams> #include <boost/uuid/uuid_generators.hpp> #include <boost/uuid/uuid_io.hpp> int main( int, char*[] ) { std::cout << boost::uuids::random_generator()() << std::endl; return 0; } This produced for me: f1633d75-ee94-47b9-ae94-37b9ee9437b9 Or wrapped to show the problem: f1633d75- ee94-47b9- ae94-37b9 ee94 37b9 Is 8 bytes of randomness enough, or is this a mistake? Best regards, Gareth ************************************************************************ The information contained in this message or any of its attachments may be confidential and is intended for the exclusive use of the addressee(s). Any disclosure, reproduction, distribution or other dissemination or use of this communication is strictly prohibited without the express permission of the sender. The views expressed in this email are those of the individual and not necessarily those of Sony or Sony affiliated companies. Sony email is for business use only. This email and any response may be monitored by Sony to be in compliance with Sony's global policies and standards

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Boost.Log formal review upcoming
by Vladimir Prus 03 Mar '10

03 Mar '10

Boosters, the formal review of the Boost.Log library, written by Andrey Semashev, will start in a week from now, on March 8, 2010 and will run through March 17, 2010. The documentation for the current version is available at: http://boost-log.sourceforge.net The downloads at at: http://sourceforge.net/projects/boost-log Because the library is relatively big and important, you might want to take a look in advance, without waiting for the formal review. Please note that reports of real-world usage will be particularly appreciated -- even if you don't have the time to to do everything formal review checklist requires please still report your experiences. To clarify timelines, the formal reviews are accepted from 23:59, March 7, PST = 2:59, March 8, EST = 7:59 March 8, GMT = 10:59, March 8 MSK until 23:59, March 17, PST = 2:59, March 18, EST = 7:59 March 18, GMT = 10:59, March 18 MSK Reviews submitted outside of this frame are not guaranteed to be processed. Thanks, Volodya

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Boost.Coroutine
by Daniel Larimer 03 Mar '10

03 Mar '10

I am attempting to use boost.coroutine; however, it is not behaving for me. Perhaps someone could shed some light? Here is what happens: 1 start coroutine A 2 do some work.... 3 my_wait_for_value() 4 future<R> f(self); 5 callback = make_callback(f); 6 r = do_wait( f ) 7 boost::coroutines::wait( f ) // blocks and the coroutine exits , goto A 8 return *f; 9 print( "here" ) 10 return r; 11 do some more work A start coroutine B B do some work C callback_from_coroutine_A ( R ) // goto line 8 D .... back to line 8 8 r = *f; // got the right future value 9 print("here") 10 return r; 11 ????? After returning r on line 10, I should end up back on line 11, but instead end up on line D. I clearly setup the future, waited, started another coroutine, set the value of the future, returned 2 levels of the stack, but the 3rd level dumped me off back in a different coroutine. Running on Mac OS X 10.6. Single threaded code. Dan

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the best possible c++ properties (implementation).
by Germán Diago 02 Mar '10

02 Mar '10

Hello. I've been trying hard to implement the best possible properties sytem in c++ (version 0x). For now, I'm quite satisfied with the result, but it can be improved a little. The properties are implemented in a header called (surprisingly!) Property.hpp Classes: template TROProperty and TRWProperty for trivial properties, which are those which you can use very straightforward without defining setters or getters and it stores the property value inside. templates RWProperty and ROProperty, for which you need to define a storage (if needed) and getters and setters. FEATURES: - You can define a getter as a function that returns *ANYTHING* and it will deduce parameters, constness and everything it needs. - You can define a setter as a function that returns void and takes one parameter. The deduction machinery will do the rest. So, for trivial properties there is little to explain: class Person { public: TROProperty<unsigned int> Age; Person(int age) : Age(age) {} }; int main(int argc, char * argv[]) { Person p(26); cout << p.Age << endl; } For elaborated properties, you have freedom in defining the get and set functions, as long as the get function gets just one parameter and the set function sets one parameter and returns void. The usage of elaborated properties is done through a macro: class Agenda { typedef Agenda ClassName; //Needed for elaborated properties. vector<Person> persons_; Person * getCurrentPerson() { return persons_[Position]; } public: TrivialProperty<int> Position; PROP_ROPROPERTY(CurrentPerson); .... Agenda() : PROP_PROPERTY_INIT(CurrentPerson) {}; }; And now it's ready to be used. For now the features are: -Implicit conversion to the underlying type. -Operator overloading (just a sample of the possible operators, just implemented operator++ and some others) -Comparison operators... -Construction assignment, etc from any other property that has a convertible type or from a data type that makes sense. - Move and copy construction where it makes sense. - Compare, for example, a Property<int> to an int or another property with a convertible value to a Property<int>. If it makes sense, it must work. The same for any other operator. - You can obtain the underlying type for a property through operator(), which makes sense in some contexts. For example, suppose you have a class Person with properties Name, SurName and Age and a class Agenda with a property CurrentPerson which returns a pointer to a Person. You can do like this: string name = agenda.CurrentPerson().Name; you can assign Name to a string or any other property that accepts a string (untested but you could). But you don't need operator() when implicit conversion takes place. personsbyage_[aperson.Age] //No need for operator(), implicit conversion Caveats: ROProperty TROProperty I cannot enforce a private operator= because for that I need a workaround I don't know of or extended friend declarations, which are part of c++0x. So for now, these properties are exactly the same as their writeable counterparts without read-only enforcement. In the implementation part, for elaborated properties I have a template like this: template <class Getter, class Setter> class RWProperty; The same goes for ROProperty. Just with that and the macro to ease the writing of properties, you can get a property. These properties must be constructed with the this pointer AND the pointer to member functions. I'm experimenting (but I can't find a way to do it) with something like this: template <class Getter, class Setter, Getter, Setter> class RWProperty; so that the construction of properties wouldn't need the pointers, because they would be passed as template parameters. But inside the template I have an ambiguity problem. Getter and Setter are pointer to member function types and Getter and Setter parameters are the addresses. For now I've found the properties very usable. The only caveats are the enforcement of operator= and the passing of pointer to members as part of initialization. If I can solve those, we can get a good properties implementation of properties and the initialization of elaborated properties would be just with the this pointer (and a value if you want to initialize with a value). This is a work in progress. For now I've used c++0x, but I think I can use BOOST_TYPEOF (maybe) and some other things in order to translate it to current c++. The code is attached. It's an (unfinished) miniapplication of an Agenda made in gtkmm compiled under g++ 4.5 svn. Take a look at the Property.hpp and the application and tell me what you think. I would like to be able to pass pointer to member functions as template arguments in order to avoid initialization of pointers as parameters. compile with: g++ -std=c++0x `pkg-config gtkmm-2.4 --libs --cflags` Person.cpp Agenda.cpp Window.cpp main.cpp -o Agenda You can just add people with "Añadir" Button and traverse with < and > button. It does not do anything special, it's just to test properties.

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Boost
by Enrique Nieloud 02 Mar '10

02 Mar '10

Hi, I just wanted to report that the following two links are broken: boost/gil/extension/numeric/sampler.hpp boost/gil/extension/numeric/resample.hpp In the file: http://www.boost.org/doc/libs/1_42_0/libs/gil/example/resize.cpp thanks, - Enrique

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[iostreams][patch] position_to_offset() is broken for Microsoft Visual C++/Dinkumware
by Sylvester-Bradley, Gareth 02 Mar '10

02 Mar '10

The recent work on Boost.Iostreams by Richard Smith and Daniel James has really improved this library. Thanks guys; this kind of maintenance is really appreciated. I have found a bug in position_to_offset() on Microsoft Visual C++/Dinkumware demonstrated by the following test app - #include <iostream> #include <boost/iostreams/positioning.hpp> int main( int, char*[] ) { const boost::int64_t twoGB = 2 << 30; std::streampos pos = boost::iostreams::offset_to_position( twoGB ); pos -= 2; if ( twoGB - 2 != boost::iostreams::position_to_offset( pos ) ) { std::cout << "Failed!" << std::endl; return -1; } return 0; } This has the potential to affect many parts of Boost.Iostreams but in particular it means the "small seeks optimization" in indirect_streambuf.hpp is broken. I believe this is resolved by the following patch to boost/iostreams/positioning.hpp. 105,106c105,106 < static_cast<stream_offset>(static_cast<std::streamoff>(pos)) - < static_cast<stream_offset>(_FPOSOFF(streampos_to_fpos_t(pos))); --- > static_cast<stream_offset>(static_cast<std::streamoff>(pos) - > _FPOSOFF(streampos_to_fpos_t(pos))); Raised on Trac: https://svn.boost.org/trac/boost/ticket/3969 Best regards, Gareth ************************************************************************ The information contained in this message or any of its attachments may be confidential and is intended for the exclusive use of the addressee(s). Any disclosure, reproduction, distribution or other dissemination or use of this communication is strictly prohibited without the express permission of the sender. The views expressed in this email are those of the individual and not necessarily those of Sony or Sony affiliated companies. Sony email is for business use only. This email and any response may be monitored by Sony to be in compliance with Sony's global policies and standards

1 0

Boost_Test: Initialize fixture only once
by Dmytro Ovdiienko 02 Mar '10

02 Mar '10

Hello All, I have a question about boost test. Please help. I have set of test_suites. Every test_suite consists of a bunch of test_cases. Every test case should be initialized before execution. So, I created Fixture for every test_suite. The problem is Fixture initialization takes a lot of time and boost creates it for every test_case (not for every test_suite) How to solve this? Best regards. Dima

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[iostreams] array and gzip_decompressor
by Nikolay Mladenov 01 Mar '10

01 Mar '10

Recently I came back to a source written some time ago, that was running then but it is not compiling now. the failing snippet is: typedef boost::iostreams::composite<boost::iostreams::gzip_decompressor, boost::iostreams::array_source> array_gzip_decompressor; boost::iostreams::gzip_decompressor filter; boost::iostreams::array_source source(&_storage[0], _storage.size()); array_gzip_decompressor dev(filter,source); boost::iostreams::stream_buffer<array_gzip_decompressor> ibuf(dev); the error is: > boost\iostreams\read.hpp(191) : error C2039: 'putback' : is not a member of 'boost::iostreams::detail::direct_adapter<Direct>' > with [ Direct=boost::iostreams::array_source ] It seems to me that gzip_decompressor requires peekable source, but array_source is not peekable. Is there another way I should be creating gzipped stream into memory? Or maybe the arrays could be made peekable? Thanks in advance, Nikolay Mladenov

3 5

boost::optional<void>
by Daniel Larimer 01 Mar '10

01 Mar '10

I am writing some generic code and would like to handle "all values" the same way; however, I keep running into the problem of return void return types that need "special treatment". There is nothing I can do about it most of the time except template specialization. That said, it would be helpful if boost::optional<void> could have some sensible default implementation where it acts more or less like a boolean. As it is, I will probably provide my own specialization of boost::optional to simplify my templates. Any thoughts on this? Dan

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[ITL][Review] A late mini review
by Thomas Klimpel 01 Mar '10

01 Mar '10

> Please always state in your review, whether you think the > library should be accepted as a Boost library. ITL should be accepted as a Boost library. > - What is your evaluation of the design? I haven't spend sufficient time reviewing the library to be able to judge the design. At least, I haven't seen any obvious flaws during my short review. > - What is your evaluation of the implementation? I took a cursory look at all source (header) files, and they look nicely written. I took a cursory look at the directory structure, to verify that it follows boost conventions. It does so in general, but I was surprised to find a "libs/itl/build" folder, since I "know" that ITL is a headers only library. The content of the build folder also didn't make me happy (it's extremely "unportable"), but this is a completely different topic that has nothing to do with this specific library. The template meta programming in boost/itl/type_traits/* could follow MPL conventions more closely. > - What is your evaluation of the documentation? The documentation is nicely written. However, please don't invent new words like "aggrovering" or "unon". Please also try to avoid changing the meaning of existing words like "neutron". > - What is your evaluation of the potential usefulness of the library? The need to work with "interval sets" arises sufficiently frequently in "time based" and "geometry based" problem domains to warrant a library dedicated especially to this problem domain. (In my review of Boost.Polygon, I pointed out that interval set concepts were missing.) I have to admit that I haven't spend sufficient time evaluating ITL to be able to judge whether ITL is able to handle all these needs. > - Did you try to use the library? With what compiler? Did you have any problems? No, I didn't try to use the library. > - How much effort did you put into your evaluation? > A glance? A quick reading? In-depth study? Some month ago, I read through the documentation just for the pleasure it gave me, pondered a bit about the concept and looked at the BoostCon2009 slide show. I was certainly planning to do a proper review during the review period, but I was (and still am) occupied with other things. What I've done now while writing this review was just a glance. > - Are you knowledgeable about the problem domain? This is not important in this case, since I haven't spend enough time for the review anyway. Regards, Thomas P.S.: As I guessed from recent experience, the review period has just been extended. However, I decided to submit this mini review nevertheless. I may have a look at "I have to admit that I haven't spend sufficient time evaluating ITL to be able to judge whether ITL is able to handle all these needs." with respect to the issue raised by Phil Endecott in http://lists.boost.org/Archives/boost/2010/02/162198.php (and write about it in case I can make up my own opinion), because this seems to be an interesting question. Even so I want to thank Phil Endecott for his courage to bring up this issue, and I guess that he is right (in a certain sense), I think it is wiser to base my review only on my personal experiences and not on my judgment of whether Phil is right or wrong with respect to this issue.

2 1

[numeric][intervall] msvc_rounding_control.hpp broken in 64 bit build.
by Juergen Hunold 01 Mar '10

01 Mar '10

Hi ! boost/numeric/interval/detail/msvc_rounding_control.hpp does not compile in x64 (64bit) build with (at least) msvc-9 The offending commit is: ------------------------------------------------------------------------ r59350 | marshall | 2010-01-29 19:01:34 +0100 (Fri, 29 Jan 2010) | 1 line Applied patches to fix #2512 and #2513 ------------------------------------------------------------------------ This does not show up in regression test because we don't have a test runner running a 64bit version of msvc. The compiler bails out on the x86 inline assembler introduced in that commit when running in 64bit mode. The simple patch is to fall back to the old behaviour using "rint" for target "x64": Index: msvc_rounding_control.hpp =================================================================== --- msvc_rounding_control.hpp (revision 59697) +++ msvc_rounding_control.hpp (working copy) @@ -25,7 +25,7 @@ namespace interval_lib { namespace detail { -#if BOOST_MSVC < 1400 +#if BOOST_MSVC < 1400 || defined(WIN64) extern "C" { double rint(double); } #else inline double rint(double x) I can apply this if necessary. Tested with msvc-9.0 I have not looked into the referenced tickets. Any (better) ideas ? Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! Ingenieurgesellschaft für * voice: ++49 511 262926 57 ! Verkehrs- und Eisenbahnwesen mbH * fax : ++49 511 262926 99 ! Lister Straße 15 * juergen.hunold(a)ivembh.de ! www.ivembh.de * * Geschäftsführer: ! Sitz des Unternehmens: Hannover * Prof. Dr.-Ing. Thomas Siefer ! Amtsgericht Hannover, HRB 56965 * PD Dr.-Ing. Alfons Radtke !

2 1

ptr_container move support
by Zachary Turner 01 Mar '10

01 Mar '10

The collections in ptr_container don't seem to support move constructors. All the recent compilers support r-value refs, has there been any discussion of adding support for this? Zach

2 1

[Serialization] extended_type_info.hpp
by fab 01 Mar '10

01 Mar '10

Hi, With boost 1.42.0, when I use BOOST_CLASS_EXPORT, I always need to include extended_type_info.hpp to resolve this error : xxx.hpp:153: error: 'guid_defined' is not a template xxx.hpp:153: error: explicit specialization of non-template 'boost::serialization::guid_defined' xxx.hpp:153: error: expected initializer before '<' token xxx.hpp:153: warning: 'boost::archive::detail::<unnamed>::init_guid<MyClass>::g' defined but not used Maybe extended_type_info.hpp can be included in export.hpp ? Fabien Castan

4 5