November 2008 - Boost - lists.preview.boost.org

bad include guards
by Steven Watanabe 26 Jan '17

26 Jan '17

AMDG The following pairs of files have identical include guards ./boost/concept_check/general.hpp ./boost/concept/detail/msvc.hpp ./boost/concept_check/msvc.hpp ./boost/concept/detail/msvc.hpp ./boost/filesystem/cerrno.hpp ./boost/cerrno.hpp ./boost/interprocess/containers/tree.hpp ./boost/interprocess/containers/detail/tree.hpp ./boost/mpl/min_max.hpp ./boost/mpl/max.hpp ./boost/mpl/vector/aux_/front.hpp ./boost/mpl/list/aux_/front.hpp ./boost/multi_index/identity_fwd.hpp ./boost/multi_index/identity.hpp ./boost/python/pointee.hpp ./boost/python/detail/pointee.hpp ./boost/spirit/phoenix/closures.hpp ./boost/lambda/closures.hpp ./boost/xpressive/proto/v1_/proto_typeof.hpp ./boost/xpressive/proto/proto_typeof.hpp ./libs/config/test/boost_no_dep_nested_class.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_mem_templates.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_std_allocator.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/conversion/test.hpp ./libs/any/test.hpp ./libs/interprocess/example/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/expand_bwd_test_template.hpp ./libs/interprocess/test/allocation_test_template.hpp ./libs/interprocess/test/printcontainer.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/iostreams/test/detail/utf8_codecvt_facet.hpp ./boost/detail/utf8_codecvt_facet.hpp ./libs/regex/test/regress/test_regex_search.hpp ./libs/regex/test/regress/test_partial_match.hpp ./libs/serialization/test/C.hpp ./libs/serialization/test/A.hpp ./libs/xpressive/perf/regex_comparison.hpp ./libs/regex/performance/regex_comparison.hpp ./tools/inspect/time_string.hpp ./tools/common/time_string.hpp In Christ, Steven Watanabe

5 8

Why no non-null smart pointers?
by Ross MacGregor 29 Apr '14

29 Apr '14

I just created a very small smart pointer libary for our project. It will contain two types of shared pointers: SharedHandle and NullableSharedHandle. SharedHandle will be a shared pointer that cannot be null by ensuring a non-null construction while NullableSharedHandle will basically be a typedef for boost::shared_ptr. I firmly believe that code can be made more reliable by minimizing the use of nullable pointers. To this end, I think it is important that we start using non-null pointer types. Ideally the compiler would be able to understand a non-null pointer and catch bugs at compile time, but I think we can still improve things with a few runtime checks. If we make sure that a shared pointer is constructed with a non-null pointer and ban any reset() type methods, we guarentee that it points to something. This can be beneficial for the following reasons: 1. Any function that uses this type will no longer be burdened with precondition checks to make sure variables of this type are not null. 2. It's type is simply more explicit and better explains its function. 3. Moving the non-null check to the creation phase will reduce the possibility of encountering null pointer exceptions at runtime (assuming there are many more pointer references than constructor calls). So my little pointer library seems to make a lot of sense, but if so why hasn't this simple smart pointer variation made it into boost yet? Has this been discussed somewhere already? My search on non-null smart pointers is not revealing much discussion on the topic. Regards, Ross

9 16

[interprocess] message_queue hangs when another process dies
by Sergei Politov 03 Nov '11

03 Nov '11

Hi, I have found the following problem with message_queue on win32 (MSVC 2008 + Windows Vista). Suppose we have 2 processes, one sends messages to queue, another reads them. When reading process dies (for instance using End process) during message_queue.receive the another process hangs in send. As I found during investigation, it tries to lock interprocess mutex, but it is already locked by dead process. So this message queue instance becomes unusable. I attached the example. Steps to reproduce: 1) Start "mq.exe s" (i.e. with argument s) It outs: sender: $PID 2) Start mq.exe without arguments. It outs: receiver: $PID 0 1 2 3 4 This time sender outs: send done: 3) At this point the message queue is empty and receiver waits for messages. End it with Task Manager. 4) Enter some number in sender console and press Enter. 5) The sender hangs in message_queue.send Best Regards, Sergei

6 13

Re: [boost] [date_time] Time zone improvements
by Rutger ter Borg 25 May '11

25 May '11

Jeff Garland wrote: > Very cool :-) One question -- is there a portable solution where a user > could deploy a files onto a Windows system or is it a Unix only solution? > I'm fine with incorporating a *nix only solution because what your > suggesting will be a nice solution for *nix platforms, but it will need to > be clear that it's not portable. I don't see why it wouldn't be possible to deploy the (big-endian) binary files to any platform. Getting it into this binary form (using zone info compiler zic) may be harder to do cross-platform, but cygwin may help here. [snip] > As the primary maintainer of Boost date-time I can say with certainty that > there is interest in this functionality -- it's long been on my todo list > and I haven't had time to get to it. You can email me privately and we > can discuss all the details of how to get your code incorporated. I'll do! Regards, Rutger

5 9

[serialization] boost/serialization/path.hpp
by Johan Råde 21 Feb '11

21 Feb '11

There is no boost/serialization/path.hpp. I suggest the following: ---------------------------------------------------------------------------------------------------------------- #ifndef BOOST_SERIALIZATION_PATH_HPP #define BOOST_SERIALIZATION_PATH_HPP // MS compatible compilers support #pragma once #if defined(_MSC_VER) && (_MSC_VER >= 1020) #pragma once #endif #include <boost/config.hpp> #include <boost/filesystem/path.hpp> #include <boost/serialization/level.hpp> BOOST_CLASS_IMPLEMENTATION(boost::filesystem::path, boost::serialization::primitive_type) #ifndef BOOST_NO_STD_WSTRING BOOST_CLASS_IMPLEMENTATION(boost::filesystem::wpath, boost::serialization::primitive_type) #endif namespace boost { namespace serialization { template<class Archive, class String, class Traits> void serialize(Archive& ar, boost::filesystem::basic_path<String, Traits>& p, const unsigned int version) { String s; if(Archive::is_saving::value) s = p.string(); ar & boost::serialization::make_nvp("string", s); if(Archive::is_loading::value) p = s; } }} #endif //-------------------------------------------------------------------------------------------------------------- Comments? Any suggested improvements? --Johan Råde

5 11

[process] How to run test cases
by Boris 23 Jan '11

23 Jan '11

As Boost.Process 0.3 has been released it would be great if the test cases are run on various platforms. So far I've tested Boost.Process on WinXP with MSVC 9.0, Cygwin with g++ 3.4.4 and Solaris with g++ 3.4.6 and Sun C++ 5.9. To make it as easy as possible for others to run the test cases here's a short description of how to proceed. Nearly all test cases depend on a program called "helpers". This program is built first and is started by many test cases as a child process. In order to find the program "helpers" the test cases must know its location. As there is no way to get the location at runtime it is hardcoded in the file libs/process/test/misc.hpp. As the location differs depending on what compiler is used YOU MUST CHECK FIRST THE PATH IN libs/process/test/misc.hpp! Otherwise most of the test cases will fail as they look for a program "helpers" in the wrong directory. As of today only those paths are correct and have been tested which are set for Windows, Cygwin and Solaris. Only after you have checked and maybe updated the path in libs/process/test/misc.hpp you should try to build and run the test cases: WinXP/MSVC 9.0 ************** With MSVC 9.0 you only need to open the Visual Studio 2008 Command Prompt, change to the directory with the test cases and run bjam: C:\boost_1_36_0\libs\process\test> ..\..\..\bjam.exe -q Cygwin/GCC 3.4.4 **************** On Cygwin it's important to know if the Boost libraries have been built for the POSIX or Windows API. By default Boost libraries on Cygwin use the Windows API. With the Windows API the Boost.Process test cases are not passed successfully though (there are compiler errors where I'm not sure currently if they are a Boost.Process problem and how they could be fixed). If you want to run the test cases on Cygwin you must (re-)build the Boost libraries to use the POSIX API: $ cd ~/boost_1_36_0 $ ./bjam cxxflags=-DBOOST_POSIX_API Afterwards you can run the test cases: $ cd ~/boost_1_36_0/libs/process/test $ ../../../bjam cxxflags=-DBOOST_POSIX_API -q Solaris/GCC 3.4.6 ***************** At first you have to put the following line in ~/user-config.jam: using gcc : : : <linker-type>sun ; Then start building the Boost libraries: $ cd ~/boost_1_36_0 $ ./bjam --toolset=gcc cxxflags=-mcpu=ultrasparc For the test cases to be passed successfully you must update Boost.Test. Change line 624 in ~/boost_1_36_0/boost/test/impl/execution_monitor.ipp temporarily to: - , m_CHLD_action( SIGCHLD, catch_system_errors, attach_dbg, alt_stack ) + , m_CHLD_action( SIGCHLD, false, attach_dbg, alt_stack ) It is important that the second parameter is false as the signal SIGCHLD should not be handled by the execution monitor and should not be reported as an error. Afterwards the test cases can be run: $ cd ~/boost_1_36_0/libs/process/test $ ../../../bjam --toolset=gcc cxxflags=-mcpu=ultrasparc -q Solaris/Sun C++ 5.9 ******************* Build the Boost libraries with the sun toolset: $ cd ~/boost_1_36_0 $ ./bjam --toolset=sun stdlib=sun-stlport For the test cases to be passed successfully you must update Boost.Test. Change line 624 in ~/boost_1_36_0/boost/test/impl/execution_monitor.ipp temporarily to: - , m_CHLD_action( SIGCHLD, catch_system_errors, attach_dbg, alt_stack ) + , m_CHLD_action( SIGCHLD, false, attach_dbg, alt_stack ) It is important that the second parameter is false as the signal SIGCHLD should not be handled by the execution monitor and should not be reported as an error. If you run the test cases now you'll get this compiler error for one test case: "../../../boost/asio/detail/socket_ops.hpp", line 218: Error: Cannot assign void* to char*. "../../../boost/asio/detail/socket_ops.hpp", line 229: Error: Cannot assign void* to char*. "../../../boost/asio/detail/descriptor_ops.hpp", line 66: Error: Cannot assign void* to char*. "../../../boost/asio/detail/descriptor_ops.hpp", line 72: Error: Cannot assign void* to char*. The bug has been reported to the Boost.Asio mailing list. If you want to build that one test case, too, you need to fix the two files in Boost.Asio 1.36.0 yourself. All the test cases can be built and run with: $ cd ~/boost_1_36_0/libs/process/test $ ../../../bjam --toolset=sun stdlib=sun-stlport -q

4 9

[asio] read_until -- possibly misleading documentation?
by Richard Smith 15 Apr '10

15 Apr '10

The documentation for Boost.ASIO (which is otherwise very comprehensive) says of the boost::asio::read_until set of overloads: | Read data into a streambuf until a delimiter is | encountered. <http://www.boost.org/doc/libs/1_35_0/doc/html/boost_asio/reference/read_unt…> What the function actually does is to read blocks of data into the streambuf, and stop when the delimiter is found. This means that frequently data beyond the delimiter will be read into the streambuf. (And this is elaborated in more detail on the individual function's pages, if a reader looks there.) I appreciate that this behaviour is compatible with the documentation, but someone less familiar with ASIO could easily assume that the function will read as far as the delimiter and no further. (And I have just spent a fair amount of time debugging a piece of code where the author had made this assumption.) Could we change the summary documentation to read something like: | Read data into a streambuf at least until a delimiter is | encountered. The implementation may read beyond the | delimiter, but will not block when doing so. While I'm on the subject of ASIO documentation, I can't see any documentation on whether the service_name parameters to the basic_resolver_query constructors are allowed to be port numbers (e.g. "80") or whether they have to be symbolic names (e.g. "http"). Port numbers work, at least on Linux, but it's not clear whether this is something that I should be relying on. Similarly for IPv4 and IPv6 addresses in the host_name parameter. Richard Smith

3 2

[TypeTraits] is it possible to add something to boost.type_traits?
by frederic.bron＠alcan.com 17 Dec '09

17 Dec '09

Dear boost implementers, TypeTraits is very useful, thanks you. However, recently, I needed something to know if a type is comparable (with operator<) and that was not in the library. Fortunately, somebody forwarded me an earlier post on the users list where I could find what I wanted. The implementation was inspired from boost/detail/is_incrementable.hpp I have written is_less_comparable, is_less_equal_comparable, is_greater_comparable... inspired from the same source and I wonder if it could be possible to add it to the library as I think it could be helpful for others. I give the source code below (if it is useful) but I am not able to make it fully general as it is in boost/type_traits. In particular, I do not understand all the macros that are used. Regards, F. Bron (See attached file: is_comparable.hpp) Avis : Ce message et toute pièce jointe sont la propriété d'Alcan et sont destinés seulement aux personnes ou à l'entité à qui le message est adressé. Si vous avez reçu ce message par erreur, veuillez le détruire et en aviser l'expéditeur par courriel. Si vous n'êtes pas le destinataire du message, vous n'êtes pas autorisé à utiliser, à copier ou à divulguer le contenu du message ou ses pièces jointes en tout ou en partie. Notice: This message and any attachments are the property of Alcan and are intended solely for the named recipients or entity to whom this message is addressed. If you have received this message in error please inform the sender via e-mail and destroy the message. If you are not the intended recipient you are not allowed to use, copy or disclose the contents or attachments in whole or in part.

11 23

proposal interval container; ITL moved to the boost sandbox
by Joachim Faulhaber 11 Nov '09

11 Nov '09

Dear boosters, after completion of a lot of boostification work I moved my Interval Template Library to the boost sandbox in the boost project centric form: https://svn.boost.org/trac/boost/browser/sandbox/itl itl boost itl [itl_xt] [validate] libs itl [itl_xt] [validate] I have split up the original library into three parts: (1) itl, (2) itl_xt and (3) validate. Core part 1 'ITL' contains all interval container class templates. Only this part will be prepared for a formal submission. Part 2 'itl_xt' contains extended parts of the original library that do not belong to the core interval container data structures and might be proposed for later extensions. Part 3 'validate' contains the sources for the law based test automaton 'LaBatea' that has been used for an automated check of the ITLs correctness. Parts 2 and 3 do not yet conform boost standards and naming conventions and are not yet intended as contributions to boost. On the core ITL-part I have done the following: + Removed all virtual functions via introduction of mixins + Integrated deeper into boost libraries replacing own code by e.g. boost::type_traits and boost::mpl + Minimized the class template interfaces by transforming member functions into non member function templates. + Made interval containers more interoperable by overloading operators and global function templates. + Wrote a test suite using boost unit test tools. Tested for boost-instance types boost::date_time and boost::rational + Provided jamfiles to build and run examples and tests. + All examples and tests have been compiled, linked and run successfully with msvc_9.0 and gcc_3.4.4(cygwin). Next I am going to write boost style html-documentation. >From the boost web page I don't see a clear recommendation for a preferable way of doing that. Handcoded? Generated with BoostBook? Is there a reference library that has an exemplary standard documentation? Cheers Joachim

3 4

Mark throw_exception as noreturn?
by Andrey Semashev 05 Jul '09

05 Jul '09

Hi, I was wondering why the throw_exception function is not marked as noreturn? This makes it troublesome to use it as a drop-in replacement for throw statements as it starts to flag compiler warnings about missing return statements in non-void functions. I suggest to mark the function as noreturn at least for compilers that support it. GCC has __attribute__((noreturn)), MSVC has __declspec(noreturn).

4 6

Proposed addition to the iterator library for iterating over all tuples.
by Alex Mendes da Costa 19 Jun '09

19 Jun '09

Hi folks: I quite often have to write code to do the following: Given N sequences, generate all the N-tuples s.t. the i'th element in each tuple is drawn from the i'th sequence. For example, if sequence S1 is { 1, 2, 3 } and sequence S2 is { 10, 20 }, I need to generate these tuples: (1, 10), (2, 10), (1, 20), (2, 20). I think this problem could be solved elegantly with a iterator similar to zip_iterator. I have some questions: (1) Is there already a way to do this in boost? (2) If not, would this be a worthwhile addition to the iterator library? (3) If so, could I contribute code for this, or must the existing library owners write it? (4) If so, how would I go about getting my code added? Most of the docs seem to be about submitting entire libraries, rather than extensions to existing libraries. Thanks, Alex

4 18

[mpl] is there a or_seq like logical metafunction?
by vicente.botet 17 Jun '09

17 Jun '09

Hello, I needs calculate the mlp::or_ of a sequence of nullary logical metafunction. This seams quite simple. I have do the following: <code> template <typename Seq> struct or_seq; template <typename Seq, long N> struct or_seq_aux : mpl::or_< typename mpl::front<Seq>::type, or_seq<typename mpl::pop_front<Seq>::type> > {}; template <typename Seq> struct or_seq_aux<Seq, 1> : mpl::front<Seq>::type {}; template <typename Seq> struct or_seq : or_seq_aux<Seq, mpl::size<Seq>::value> {}; </code> Is there a boost or_seq like logical metafunction? Is there a better way to do it? I would be extremely interested in any suggestions. Best regards --------------------------- Vicente Juan Botet Escriba

5 34

Proposed templated integer_sort
by Steven Ross 25 Apr '09

25 Apr '09

Would there be interest in an integer_sort call that is faster than std::sort? Spreadsort is an in-place hybrid radix-based and comparison-based algorithm with better worst-case and average-case (roughly 20-50%) performance than introsort on random integer data. The worst-case advantage is algorithmic, with Spreadsort taking the better of O(n(square_root(bit_sizeof(data) - log(n)))) and O(nlog(n)) time. For 32-bit integers, that's O(n(square_root(32 - log(n)))), so for a log(n) of 16 (65536 items), it's 4n (plus a small constant times n), vs 16n for introsort. For larger n, the advantage vs. pure comparison-based algorithms increases. In effect, Spreadsort smoothly transitions from pure MSB Radix sort to std::sort with its data cut up by a couple iterations of MSB Radix sort (reducing the size of the log(n) factor), depending upon the distribution and size of the data. I could write a templated version of Spreadsort for the Boost library if there is interest. It would work for anything that supports the << and - operators. It could also handle standard floats sorted as integers. Functors supporting << and - could make it more general. Multi-dimensional sorting is also sped up by Spreadsort. I could also write a similar string_sort, that should also be significantly faster than std::sort. This would look much like postal sort, just using introsort after a certain number of iterations. Is this of interest? http://sourceforge.net/projects/spreadsort

15 118

Boost.Process 0.3 released
by Boris 14 Apr '09

14 Apr '09

I've released Boost.Process 0.3. Here's the documentation and a link to download the zip archive: Docs: http://www.highscore.de/boost/process/ Code: http://www.highscore.de/boost/process.zip It's a header-only library and thus pretty easy to use: Just copy the files to your Boost directory. In this release my main goal was to merge various snapshots: * There was my Boost.Process 0.2 version which was based on Boost.Process 0.1 from 2006. * There was a post-0.1 version of Boost.Process in SVN from 2007. * Chris Fairles had modified a Boost.Process snapshot for Unix platforms. * Ion Gaztañaga had also some ideas and bug fixes he sent to this mailing list recently. I just saw that Ilya Sokolov created another snapshot based on Boost.Process in SVN. That means we have again at least two different versions of Boost.Process. :-/ In my Boost.Process 0.3 version I concentrated on merging and overhauling code. I did not change the design but tried to make the code work: All the code which was written since 2006 should become usable. That's why I also concentrated a lot on test cases. There are quite a lot of test cases, and they all can be built and passed successfully on three platforms with four compilers. As it would be great if others run the test cases, too (ideally on new platforms), I'll send another message in a few minutes with a description how to run the test cases yourself. As the documentation was written in 2006 I also updated it. It's not yet really a good documentation: There are some files coming from 2006 while other files I wrote myself only last week. While the documentation can be improved it's at least up-to-date: The examples all work and can be compiled. As the documentation was not my priority for Boost.Process 0.3 it should be ok for now. Boris

9 14

Final report of GSOC project 'Spatial Indexes'
by Federico J. Fernández 27 Mar '09

27 Mar '09

Hi List! I'm writing this email as a final report of my Google Summer of Code 2008 project for Boost. My project consist in adding some spatial indexing structures to Boost in the context of the Geometry proposal done by Barend Gehrels. Spatial indexes are data structures optimized for spatial oriented queries. The classic index structures (i.e. a binary tree) aren't spatially enabled, they have different ordering criteria but none of them relates to topological properties. The scope of these structures is really wide, from collision detection for games to geometry indexing for GIS software. The original project goals were: - Build a Quadtree. - Build an rTree. - Integrate some previous work from a former GSoC project of a k-d-tree. - Test and document everything. Both indexes are implemented now and everything is tested and documented. The only task that we didn't complete is the k-d-tree integration, because when we analyzed the code it was not ready, and we didn't have the time to finish it. About the results, we made several tests and benchmarks. We tested both indexes with 230.000 objects from GIS data to check the correctness of the implementation, and we made some benchmarks comparing the quadtree vs. rtree and comparing both of them to existing implementation (like GEOS) with very good results. We describe this benchmarks in the documentation offering this as a guide to choose the best index for each use. The code is still beta (or maybe alpha) and not recommended for production use because it is still not tested enough, but if you want to check the actual status you can find it in the following location: https://svn.boost.org/svn/boost/sandbox/SOC/2008/spacial_indexing/ And the docs are at: https://svn.boost.org/svn/boost/sandbox/SOC/2008/spacial_indexing/libs/spat… The future work now is huge. We have some ideas about integrating this in some way to multindexes, and we want to implement also a 'packed' version of the rtree to improve bulk-loading times among another things. Finally, I would like to thank to Boost for allowing me to be part of this year's SOC. And specially to my mentor Hartmut Kaiser for all his help during the program. -- federico j. fernandez

8 13

[endian] superfluous boost::operators<> ?
by Roland Schwarz 26 Mar '09

26 Mar '09

I discovered, that the following will not compile: unsigned u; ulittle32_t u1; ulittle32_t u2; u = 1; u1 = 1; u2 = u1 + u; The compiler complains about not being able to resolve similar conversions. My guess is, that using boost::operators<> _and_ providing type conversion operators at the same time is causing this. I think it should be enough to define the essential operators in cover_operators template, and omit boost::operators<> at all. At least I am not able to find any problems with this, since the compiler adjusts the arguments (using the provided type conversion operators?) and calls the built in operators, thereby resolving ambiguity. Any thoughts? -- _________________________________________ _ _ | Roland Schwarz |_)(_ | aka. speedsnail | \__) | mailto:roland.schwarz@chello.at ________| http://www.blackspace.at

2 1

Re: [boost] [Boost-users] Maintenace Guidelines wiki page
by vicente.botet 15 Mar '09

15 Mar '09

----- Original Message ----- From: "Tomas Puverle" <Tomas.Puverle(a)morganstanley.com> To: <boost-users(a)lists.boost.org> Sent: Sunday, November 23, 2008 4:31 AM Subject: Re: [Boost-users] Maintenace Guidelines wiki page > >> I have started the Maintenace Guidelines wiki page. >> >> You can access it directly >> https://svn.boost.org/trac/boost/wiki/Guidelines/MaintenanceGuidelines >> >> or via https://svn.boost.org/trac/boost/wiki >> >> Guidelines >> * Maintenance Guidelines >> >> There page need to be completed and surely reworked but this is an starting >> point. >> >> Please be free to improve the page directly or post your comments or > suggestions to this list. >> >> Hopping this goes on the right direction, > > Vincente, > > A few ideas: How will you evaluate that your proposal is actually successful > and being followed by the boost developers? Hi, First this is proposal for guidelines. So people will be after all free to follow some of them or not. I'm expecting from people like you to improve it so it could be followed by more people. > Also, check out Daniel Walker's idea in the Boost.Range thread on boost.devel > about not having the engineers in charge of their own QA. Daniel Walker's idea " Perhaps a procedural solution that could avert this problem in the future is to quarantine the test cases. Authors can maintain commit privileges to their libraries on trunk, but only a select group of independent guardians have commit privileges to the test cases. That way there is a guarantee that libraries pass the same tests from one release to another. If an author would like to make a change that would break a test case, he or she would need to present the change to the list and submit a patch to the test case sentinels. This would be a fairly simple quality assurance protocol: engineers aren't allowed to do their own QA." This is already considered on the guidelines insome way. "Preserve the test from the preceding versions [author] The test from the preceding versions should not be changed when the author modifies its library. These not changed tests are a probe of compatibility with the preceding version. When these test must be changed they indicate a breaking user code issue. So instead of changing them add new ones stating explicitly on which version they were included. Old tests that should fail can be moved to the compile_fail or run_fail tests on the Jamfile. " The Daniel proposal implies some changes in the writing rights of the authors. I prefer to let this point out of these guidelines. Of course I think that this is a good idea. There is another guideline that could be used by the Boost comunity to check the author has not changed the old test cases. "Inspect announced modifications [author, user, RM] The use of the diff file will help to inspect that the modifications introduced have been correctly included on the documentation and a good test coverage has been done. This will result in a non official mini-review of the library. " I will add to check that the old testcases have not been changed. > Finally, please consider the idea of "core" and "new" release cycles, where the > components in "core" have much more stringent requirements on how and when they > are allowed to change. IMO this is out of the scope of the guidelines. Note that at the end it is up to the author to make the modification he/she consider pertinent. Could you send what you have in mind in the form of guidelines? > Finally, do you think it may have been better to start this thread on > boost.devel? I belived that i did it on both. I'm answering to both each time. Should I start a new thread including the guidelines contents? Vicente

14 46

Design conventions; passing functors
by Joachim Faulhaber 04 Mar '09

04 Mar '09

Hi, I am pondering about functor passing. Functors occur in my library (ITL) e.g. for the aggregation of associated values on insertion in interval_maps (aggregation on overlap): template<class Domain, class Codomain, ...> class interval_map{ ... //(1) My current implementation is this: // Combinator is the aggregating functor template, // instantiated at compiletime template<template<class>class Combinator> interval_map& add(const value_type& value_pair) { /*Combinator template passed or instantiated somewhere*/ } ... } //I like this definition, because it's abstract: // The functor has to be a matching template e.g. inplace_max interval_map<int,int> m; m.add<inplace_max>(some); //(1) template<class Domain, class Codomain, ...> class interval_map{ //(2) The more traditional definition template<class Combinator> interval_map& add(const value_type& value_pair) { /*Combinator type passed or called somewhere*/ } ... m.add<inplace_max<int> >(some); //(2) I prefer (1) but both definitions (1) and (2) are purely static denotations. To have adaptable functors or functors that can have states, like in ... m.add(some, max_under(42)); ... I am afraid I have to say sayonara to definition (1) and use this instead: template<class Domain, class Codomain, ...> class interval_map{ //(3) Adaptable functor template<template<class>class Combinator> interval_map& add(const value_type& value_pair, const Combinator<Codomain>& combine) { /*combine functor passed or called somewhere*/ } Now, there seems to be a convention from the STL that functors shall be passed BY VALUE. template<template<class>class Combinator> interval_map& add(const value_type& value_pair, Combinator<Codomain> combine); This is stated in [Sutter & Alexandrecu 2005, C++ Coding Standards] item 89: "Function objects are modeled on function pointers. Like function pointers, the convention is to pass them by value. All of the standard algorithms pass objects by value, and your algorithms should too." I do not really understand this convention and feel some resistance to follow it. In addition the call by value implementation can (and will) lead to heavy inefficiency by unaware usage of fat functors. So I browsed through some boost libraries and found that functors are passed by reference there (e.g. accumulators, fusion). Final question: What is the boost standard on passing functors, that I can adapt to? Cheers Joachim

6 20

N2346 - Defaulted and Deleted Functions emulation
by vicente.botet 02 Mar '09

02 Mar '09

Hi, is there an interest in a N2346 - Defaulted and Deleted Functions emulation http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2346.htm The idea been to use some macros that will use the =default, =delete if the compiler provides it and replace this macros by whatever has the same semantics. Alexandrescu introduced already two macros NON_ALIAS and NON_HEAP_ALLOCATED when talking about strict locks. Attached a draft for the default and deleted functions. Only one remark the macors must be used on the public part and without trailing ';', e.g. class X { BOOST_NEW_DELETE(X) Any coments are welcome, Vicente

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Profiling template instantiations
by Steven Watanabe 12 Feb '09

12 Feb '09

AMDG Over the last few days, I've been working on a tool that counts the number of class template instantiations in a translation unit. To use it from a jamfile import profile_templates : : directory of the tool ; template-profile result : some_file.cpp : <include>some_directories ; If everything works, this will create a file with the extension .tp which will contain the number of times each class template was instantiated, with the most common templates at the top. I've put a zip of a rough version in the vault. http://www.boost-consulting.com/vault/index.php?action=downloadfile&filenam… Caveats: I've only tested with Visual C++ 9.0 and gcc 3.4.4 on cygwin so far. Other compilers won't work, yet. Other versions of these compilers may or may not work. It may be necessary to add link=static to the bjam command line. In Christ, Steven Watanabe

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Re: [boost] Profiling template instantiations (Steven Watanabe)
by PORKOLAB Zoltan 12 Feb '09

12 Feb '09

Hi Steven, We have created a framework for debugging/profiling template metaprograms in 2006. It might give you a few tips. It works based on the same idea you have. We instrument all template codes, both at the begining and at the end of each template we insert a special piece of code emitting warning messages of a well-defined form. Before instrumentation we create an XML file to remember the template positions in the source file. When we parse the warning, using this information we can reconstruct the instantiation stack knowing the original line numbers, identifiers, etc.. At the end we produce another XML for possible front-ends. The framework uses boost::spirit and boost::wave. We have also implemented and tested a visual studio plug-in. An overview of the whole idea: http://gsd.web.elte.hu/templight/ There is also a GPCE article about the framework, you can find it here: http://portal.acm.org/citation.cfm?id=1173746&coll=portal&dl=ACM&CFID=47731… or here: http://gsd.web.elte.hu/contents/articles/gpce06.pdf You can download both the VS binaries and the source from: http://people.inf.elte.hu/pocok Please feel free to use the code or any of the ideas. For technical question you can find Jozsef: jmihalicza(a)gmail.com or me. Regards, Zoltan

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[constrained_value] Review version
by Robert Kawulak 09 Feb '09

09 Feb '09

Hi all, I've made some minor changes to the Boost Constrained Value library: - reorganized the structure of header files, - renamed saturating/saturating_int into clipping/clipping_int, - using boost::swap where applicable (if you don't have it, you need to get it from http://svn.boost.org/svn/boost/branches/release/boost/utility/swap.hpp) - made no_constraint policy public, - now the stream operators are not defined if BOOST_NO_IOSFWD macro is defined, - fixed identifiers containing "__" (not allowed by C++), - fixed minor language errors in the docs. The library is ready for the formal review, which starts this monday (1.12). It is only missing the detailed regression tests, which will be added after the review. Currently the examples file (libs\constrained_value\doc\src\examples.cpp) can be used instead -- it uses most of the functionality of the library and should compile and run returning 0. As usually, the code and documentation can be downloaded here: http://rk.go.pl/f/constrained_value.zip The documentation is also available online here: http://rk.go.pl/r/constrained_value Any comments and problem reports for platforms that has not been tested yet are very welcome. Best regards, Robert Kawulak -=##############=- "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein

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[threadpool] new version - supporting future library (C++0x) from Anthony Williams
by k-oli＠gmx.de 09 Feb '09

09 Feb '09

Hello, I've uploaded a new version of boost.threadpool (v17) at http://www.boostpro.com/vault/index.php?action=downloadfile&filename=boost-…. It uses the future implementation of Anthony Williams (C++0x - available at http://www.justsoftwaresolutions.co.uk/files/n2561 future.hpp). Please save it as file 'future'. best regards, Oliver

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Re: [boost] [date_time] Time zone improvements
by Rutger ter Borg 07 Feb '09

07 Feb '09

Jeff Garland wrote: > Very cool :-) One question -- is there a portable solution where a user > could deploy a files onto a Windows system or is it a Unix only solution? Portable, big endian binary files. The variant I'm proposing is also based on the POSIX standard http://www.opengroup.org/onlinepubs/000095399/basedefs/xbd_chap08.html: "TZ This variable shall represent timezone information. The contents of the environment variable named TZ shall be used by the [snip] functions, and by various utilities, to override the default timezone. The value of TZ has one of the two forms (spaces inserted for clarity): :characters or: std offset dst offset, rule " The second variant is what's currently in Boost.Date_Time as Posix Time Zone, having a direct specification of the time zone. I'll be talking about the first variant, containing :characters. Although this is implementaiton specific, most POSIX-compatible systems have implemented the Zoneinfo database for this variant, e.g., Linux-based systems, many BSDs, Mac OS X, etc. The :characters point to any other zoneinfo-compatible binary file, either with an absolute or relative path. A natural step for changing Boost.Date_Time would be to make changes such that the Posix Time Zone supports both formats. I.e., variant 1) posix_time_zone( ":/etc/localtime" ); or posix_time_zone( ":/usr/share/zoneinfo/Europe/Amsterdam" ); variant 2) posix_time_zone( "EST-5EDT,M4.1.0,M10.5.0" ); I think both should work as it is from the same standard, and seems to be a natural and consistent starting point to look at changing the interface. Do you agree? > Actually, I believe the abstract timezone is able to support this, but > there > isn't a concrete implementation. It would be great to have the concrete > implementation to prove out the abstraction (obviously from the text below > you think there needs to be changes). As far as I can tell, the abstract time zone class currently is not able to represent variant 1): the abstract zone class is geared towards a single-lined definition of a time zone, whereas variant 1) may be regarded as a series of definitions, i.e., a map of < transition_time_point_in_utc, { gmt_offset, abbreviation, is_dst, ... } > looking up utc_to_local is a matter of doing a lower_bound search on the transition time points. The right-hand side of the map above is widely implemented with a struct called ttinfo. A proposal from my side would be to change the abstract time zone class in such way that it is able to represent both variants. The easiest approach here is probably to introduce the ttinfo structure, and make the current library working with that. variant 1): has a map of transition points, returns a (pointer to a) ttinfo structure. May hold more than 2 different ttinfo structures. variant 2): always has 2 ttinfo structures (std/dst). Uses dst-calculations/functions to lookup the transitions point, returns the right (pointer to a) ttinfo structure. What do you think? Cheers, Rutger

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[threadpool] draft n2276 - launch_in_pool
by Oliver Kowalke 25 Jan '09

25 Jan '09

Hello, I did a look into draft n2276 - a launch_in_pool function is suggested (passing task to a system provided threadpool). Is it reasonable to have a static threadpool? How many worker-threads should this pool contain and how are the submitted tasks queued (FIFO, priority order ... unlimited/limited number of tasks can bes stored). What about applications which require a pool with different configuration than the static pool provides? Is it acceptable to pay for an unused pool? regards, Oliver -- Psssst! Schon vom neuen GMX MultiMessenger gehört? Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger

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