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[Xpressive] vs libpcre performance
by Sebastian Redl 14 Sep '08

14 Sep '08

Hi, A German journal recently published a small programming contest with a very simple text processing problem. The program needs to renumber and sort footnotes in a long text. I wrote a solution in C++ using a number of Boost libraries, among them Xpressive, but also Interprocess for memory-mapping the input file. Then I looked at the submissions page and found one C++ solution already there, an admirably short (but rather inflexible) program using libpcre. http://www.linux-magazin.de/static/listings/magazin/2008/10/leser/cpp/footn… Comparing the performance, my program was sightly but consistently slower than this small program, even when I felt that my usage of memory-mapping and then scanning the whole file instead of going line by line ought to give me a speed advantage. So to test the performance I took the existing submission and replaced libpcre with Xpressive (see attached file). I believe the solutions to be functionally equivalent. However, the original takes 6 seconds to process a 55MB file, whereas my variation takes ~15 seconds. That's on the second run of each program, meaning that the entire file is in the OS cache. This seems awfully slow. Has anyone done a proper performance comparison between Xpressive and libpcre? Boost.Regex's performance pages lists PCRE, but in version 4.1, where 7.8 is the most recent release. My system: Athlon 64 2000MHz (64-bit mode) 1GB RAM Linux 2.6.23, GCC 4.1.2 Boost trunk as of 2008-09-11 libpcre 7.7 Sebastian Redl

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warnings in tests
by Emil Dotchevski 13 Sep '08

13 Sep '08

In Boost testing, wouldn't it be a good idea to have a script that scans the output generated from each successful test for the word "warning" and indicate its presence in the test matrix? Perhaps leave the box green but instead of "pass" have it say "pass/w" or something. Without this, platform-specific warnings can only be addressed after they're reported by the end users. Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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[Dataflow] [Review] Dataflow review has ended
by jarvi＠cs.tamu.edu 13 Sep '08

13 Sep '08

The number of reviews for the dataflow library was very low (one, positive). Rather than extending the review period in hopes for more reviews, the review period of the data-flow library is now over, and at this time the library is not accepted as a Boost library. The discussions indicated that there's some confusion regarding the library's role; this concern needs to be addressed prior to moving forward with the library. Stjepan is content of the feedback received during the review, and will use it to clarify the library's documentation and further develop the library. He intends to bring the library for review again when the concerns raised have been addressed. Even though the review period is over, I encourage everyone to submit their comments, half-written reviews, reviews that you were planning to write, etc. as those will help Stjepan in his efforts in improving the library. Thank you for everyone for participating in the review, and thank you Stjepan for your work for Boost! Jaakko Järvi Review Manager

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[thread_pool]: formal review request
by Oliver Kowalke 12 Sep '08

12 Sep '08

Hello, I'd like to request a review of my thread_pool library - it is available at the boost vault/Concurrent Programming. The library provides: - thread creation policies: determines the managemnt of worker threads - fixed set of threads in pool - create workerthreads on demand (depending on context) - let worker threads ime out after certain idle time - channel policies: manages access to queued tasks - bounded channel with high and low watermark for queuing tasks - unbounded channel with unlimited numer of queued tasks - rendezvous syncron hand-over between producer and consumer threads - queueing policy: determines how tasks will be removed from channel - FIFO - LIFO - priority queue (attribute assigned to task) - smart insertions and extractions (for instance remove oldest task with certain attribute by newst one) - tasks can be chained and lazy submit of taks is also supported (thanks to Braddocks future library). - returns a task object from the submit function. The task it self can be interrupted if its is cooperative (means it has some interruption points in its code -> this_thread::interruption_point() ). Oliver -- GMX Kostenlose Spiele: Einfach online spielen und Spaß haben mit Pastry Passion! http://games.entertainment.gmx.net/de/entertainment/games/free/puzzle/61691…

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[Iterator] Zip iterator for back_insert_iterators?
by Kris Rousey 12 Sep '08

12 Sep '08

I just tried to make a zip iterator out of two vector back_insert_iterators and got a very curious compile failure: /usr/include/boost/iterator/iterator_facade.hpp:653: error: invalid parameter type 'void' /usr/include/boost/iterator/iterator_facade.hpp:653: error: in declaration 'typename boost::detail::operator_brackets_result<Derived, Value, Reference>::type boost::iterator_facade<I, V, TC, R, D>::operator[](Difference) const' /usr/include/boost/iterator/iterator_facade.hpp:693: error: invalid parameter type 'void' /usr/include/boost/iterator/iterator_facade.hpp:693: error: in declaration 'Derived& boost::iterator_facade<I, V, TC, R, D>::operator+=(Difference)' /usr/include/boost/iterator/iterator_facade.hpp:699: error: invalid parameter type 'void' /usr/include/boost/iterator/iterator_facade.hpp:699: error: in declaration 'Derived& boost::iterator_facade<I, V, TC, R, D>::operator-=(Difference)' /usr/include/boost/iterator/iterator_facade.hpp:705: error: invalid parameter type 'void' /usr/include/boost/iterator/iterator_facade.hpp:705: error: in declaration 'Derived boost::iterator_facade<I, V, TC, R, D>::operator-(Difference) const' It seems that even though back_insert_iterator has an output_iterator tag, iterator_facade still trying to define random access operators. If assignment and incrementing are the only valid operations on an iterator (as is the case with output iterators), then doesn't it make sense to support a difference_type of void? Is this a curiosity of my stdlib implementation? A Boost.Iterator library oversight? A Boost.Iterator conscious design decision? Or a loose nut behind the keyboard trying something he shouldn't? I'm using version 1.35.0 on Ubuntu 8.04 x86_64 with g++ version 4.2.3. Here's the code I used to get this error: #include <iterator> #include <iostream> #include <boost/iterator/zip_iterator.hpp> #include <vector> #include <algorithm> using namespace std; using namespace boost; int main() { vector<int> ha1; vector<double> ha2; make_zip_iterator( make_tuple( back_inserter(ha1), back_inserter(ha2) ) ); return 0; } Thanks, Kris

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[In_Place_Factory] Typo
by Manuel Jung 12 Sep '08

12 Sep '08

Hi, I found a typo: Here: http://www.boost.org/doc/libs/1_36_0/libs/utility/in_place_factories.html Chapter: Framework In the First example: struct C { template<class InPlaceFactory> C ( InPlaceFactory const& aFactoty ) //<----------Here! should be "aFactory" : contained_ ( uninitialized_storage() ) { aFactory.template apply<X>(contained_); } ~C() { contained_ -> X::~X(); delete[] contained_ ; } char* uninitialized_storage() { return new char[sizeof(X)] ; } char* contained_ ; } ; void foo() { C c( in_place(123,"hello") ) ; } Greetings Manuel

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Re: [boost] HP-UX_pa_risc_aCC test failure
by Kotari, Preethi (STSD) 12 Sep '08

12 Sep '08

Hi, We are investigating this issue and will keep you updated with the progress. Thanks, Preethi > -----Original Message----- > From: boost-bounces_at_[hidden] > [mailto:boost-bounces_at_[hidden]] On Behalf Of Emil Dotchevski > Sent: Tuesday, September 09, 2008 3:29 PM > To: boost_at_[hidden] > Subject: [boost] HP-UX_pa_risc_aCC test failure > > I'm looking at this failure: > > http://www.boost.org/development/tests/trunk/developer/output/ > HP-UX_pa_risc_aCC-boost-bin-v2-libs-exception-test-throw_excep > tion_test-test-acc-pa_risc-debug.html > > The assertion is an indication that a particular function that throws > an exception returned without throwing an exception. Does this > platform support exception handling? If not, shouldn't > BOOST_NO_EXCEPTIONS be #defined? > > Emil Dotchevski > Reverge Studios, Inc.

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Re: [boost] [hash] Is there any interest in cryptographic hash functions?
by Kasra (Math & ComSci) 12 Sep '08

12 Sep '08

I am back from being busy => I am free. I have thought about the design decisions: "It doesn't really make sense to hook this up to an fstream. Such a remove_file_securely() functionality should be implemented as free function." I disagree, say you have a file 'x' which you don't want the local police to be able to recover, and you have a 'xx' file which you don't want the FBI to be able to recover (a little too hard to achieve). Here the security differs, and thus the wipe method ought to be different. secure_wipe< aStream, onePassAlgorithm > x; // single overwrite secure_wipe< aStream, gutmannAlgorithm > xx; // 35 x overwrite "Well there are two classes of ciphers, block ciphers and stream ciphers. Block ciphers encrypt data by working on x bytes at a time. Stream ciphers on the other hand (like RC4) encrypt data continuously and don't need a padding parameter because they don't need to pad data to a multiple of some block size. So what you call a cipher is a stream cipher. I see now where you're going with this and I will think about it. " In general blocks cipher is an element of stream cipher which in turn is an element of cipher set. So I guess the terminology doesn't bother me much. But I think you know where I am coming from now. "I remember that table lookups generally are susceptible to cache timing attacks. That does not mean we shouldn't use the optimized rijndael version though." I totally agree with you, the cache-timing attack is believed to be impossible on more than 1 network loop. I have written the wrapper class for the optimised implementation. Conclusion: All of us like: * basic_crypto_stream. * optimised implementations Haven't agreed on yet but are thinking in the same lines: * block_cipher, stream_cipher, cipher thing Disagree on: * secure_wipe I agree 'secure_wipe' is not very useful for a memory buffer. A secure allocator works fine (i.e. memset() ). But on the other hand when it comes to files 'secure_wipe' is very useful. So we need to agree on the interface which the 'secure_wipe' task is achieved. With best regards, kasra

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[svn] creating branches?
by JOAQUIN M. LOPEZ MUÑOZ 11 Sep '08

11 Sep '08

Hello, Do I need a special permission to create branches in the Boost SVN repository under the branches/ folder (I have read/write permissions) ? I just tried and I'm getting the following: Error: MKACTIVITY of '/svn/boost/!svn/act/61476d52-5ac2-7d42-a98b-eb1ac421fec1': 403 Forbidden (http://svn.boost.org) My level of SVN expertise is "dumb rookie", so please bear with me if I'm doing something really stupid :) Thank you, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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Re: [boost] Improving the assignment operators of various Boosttypes
by Gevorg Voskanyan 11 Sep '08

11 Sep '08

David Abrahams wrote: > If you're asking whether such functions should be documented as nothrow > after the modification, I think they should: it could be useful > information for move-only types (with nonthrowing move ctors). Yes, documenting the operators as nothrow is what I had in mind, thanks! Best Regards, Gevorg

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Re: [boost] Improving the assignment operators of various Boosttypes
by Gevorg Voskanyan 11 Sep '08

11 Sep '08

David Abrahams wrote: > on Thu Sep 11 2008, Gevorg Voskanyan wrote: [snip] > > AFAIU, a swapping assignment operator taking the parameter by const ref > adheres > > to the strong exception safety guarantee, whereas the one taking the parameter > > by value fulfills the nothrow guarantee. Not sure how practical and/or > relevant > > the difference in this context is, though. > > > > Is my observation above correct? > > Well, technically, yeah... although the expression that does the > assignment can still throw, so I don't think it makes much difference to > say that it's nothrow. In other words, if I give you > > f(std::string); // nothrow > g(std::string&); // strong guarantee > > For all practical purposes, you know that f and g have equivalent > exception behavior because std::string's copy ctor can throw. True, that's why I questioned the practicality of this difference :) Except perhaps for documenting a function's exception safety. Should it be considered while making aforementioned assignment operators in boost to take the argument by value? > I think this calculus might get more interesting when rvalue references > are involved, because you can actually write stronger conditional > guarantees. My early impression is that rvalue references are going to make life much more interesting :-) Thanks for your time, Dave! Best Regards, Gevorg

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Re: [boost] Improving the assignment operators of various Boosttypes
by Gevorg Voskanyan 11 Sep '08

11 Sep '08

David Abrahams wrote: > on Thu Sep 11 2008, Gevorg Voskanyan wrote: [snip] > > AFAIU, a swapping assignment operator taking the parameter by const ref > adheres > > to the strong exception safety guarantee, whereas the one taking the parameter > > by value fulfills the nothrow guarantee. Not sure how practical and/or > relevant > > the difference in this context is, though. > > > > Is my observation above correct? > > Well, technically, yeah... although the expression that does the > assignment can still throw, so I don't think it makes much difference to > say that it's nothrow. In other words, if I give you > > f(std::string); // nothrow > g(std::string&); // strong guarantee > > For all practical purposes, you know that f and g have equivalent > exception behavior because std::string's copy ctor can throw. True, that's why I questioned the practicality of this difference :) Except perhaps for documenting a function's exception safety. Should it be considered while making aforementioned assignment operators in boost to take the argument by value? > I think this calculus might get more interesting when rvalue references > are involved, because you can actually write stronger conditional > guarantees. My early impression is that rvalue references are going to make life much more interesting :-) Thanks for your time, Dave! Best Regards, Gevorg

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Re: [boost] Improving the assignment operators of various Boosttypes
by Gevorg Voskanyan 11 Sep '08

11 Sep '08

Giovanni Piero Deretta wrote: > If you do not want to deal with move emulation (which I've found very > brittle in complex expressions), a simple way to to gain the advantage > of T::operator=(T rhs) even when assigning from lvalues is something > like: > > templateT destructive_copy(T& x) { > using std::swap; > T result; > swap(result, x); > return x; > } > > which relies on NRVO to eliminate expensive copies: Shouldn't the last statement be return result; instead? Or maybe I am missing something? Best Regards, Gevorg

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Re: [boost] Is self assignment test valid?
by David Abrahams 11 Sep '08

11 Sep '08

on Mon Sep 08 2008, "Niels Dekker - no return address" <noreply-AT-this.is.invalid> wrote: > Andrei Alexandrescu wrote: >> JoshuaMaurice (at) gm...com wrote: >>> As an aside, the way I've generally done it is as follows, which >>> I assume to be equivalent to the two previous examples. >>> >>> struct T >>> { >>> T& operator= (T const& x) >>> { >>> T(x).swap(*this); >>> return *this; >>> } >>> void swap(T& x); >>> }; >> >> That's the politically correct version. It turns out that, when a >> function needs to make a copy of its argument, it better takes it by >> value in the first place. That way, if an rvalue is passed in, the >> compiler can directly fuse the rvalue to the parameter thus saving a >> copy. > > Do you think this is still relevant when operator= is inline, and it's just > doing "T(x).swap(*this)"? Absolutely. The compiler is allowed to elide the implicit copy when the argument is an rvalue if the corresponding parameter is taken by-value. However, when you write T(x) and x is an lvalue (as it is inside the operator= above), the compiler is required to honor your explicit instruction to make a copy of x. > If so, I might consider submitting another ticket regarding > boost::function, which still copy-assigns in the "politically correct" > way at the moment. As so many of us do :-) Could you do that for all the other libraries too? I'm serious, I've been meaning to make a sweep across the source code to fix this. >> See http://www.erdani.org/publications/cuj-02-2003.html > > Thanks! Looking a the example of passing the result of MakeUrl() to the > function Connect(const String& url), you wrote: "For a compiler to optimize > away the copy, it has to do the Herculean job of (1) getting access to > Connect's definition (hard with separately compiled modules), (2) parse > Connect's definition to develop an understanding of it, and (3) alter > Connect's behavior so that the temporary is fused with finalUrl." > > Now is it still such a Herculean job for a compiler to do so for an /inline/ > assignment operator that's only just swapping a temporary copy? Honestly, I > haven't done any profiling on this, so I just hope you did so already :-) Yes, it's still a fairly herculean job. The compiler would have to prove that the entire program works exactly the same way with or without the copy, proving that nothing about the address or identity of the new T is significant. While it's possible that someone might implement that optimization for some cases where T's copy constructor, swap, and destructor are all inlined, that level of understanding is not typically developed in optimizers. In the case of copy-elision for by-value arguments and return values, the compiler is explicitly allowed to _assume_ there is no semantic difference between the original rvalue and its copy. That's low-hanging fruit for a compiler writer, that pays huge dividends. -- Dave Abrahams BoostPro Computing http://www.boostpro.com

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HP-UX_pa_risc_aCC test failure
by Emil Dotchevski 11 Sep '08

11 Sep '08

I'm looking at this failure: http://www.boost.org/development/tests/trunk/developer/output/HP-UX_pa_risc… The assertion is an indication that a particular function that throws an exception returned without throwing an exception. Does this platform support exception handling? If not, shouldn't BOOST_NO_EXCEPTIONS be #defined? Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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Re: [boost] Improving the assignment operators of various Boosttypes
by Gevorg Voskanyan 11 Sep '08

11 Sep '08

David Abrahams wrote: > on Wed Sep 10 2008, "Scott McMurray" wrote: > > > On Wed, Sep 10, 2008 at 21:23, Joe Gottman wrote: > >> Joel Falcou wrote: > >>> > >>> I may come late and maybe like an unwanted guest in this discussion but I > >>> am curious to know how i can know that for a given class of mine, the swap > >>> value operator= is better than the by const ref operator= ? > >>> > >> > >> My rule of thumb is that if your assignment operator might throw an > >> exception and you want assignment to fulfill the strong exception safety > >> guarantee (i.e. either the assignment succeeds or the target remains > >> unchanged) then you should consider the swapping operator=. > >> > > > > I would even go slightly more expansive than that and say "Use the > > swapping operator= unless you've explicitly decided you want less > > exception safety (like for efficiency reasons in std::vector)". > > > > It means one fewer place that needs updating when members change, and > > I suspect -- though I have no supporting data -- that the optimizer > > should make the swapping version "good enough" in most cases. > > Swapping and taking the parameter by value are orthogonal issues; the > latter has only to do with copy elision and not with exception safety. > Please see this thread: > http://groups.google.com/group/comp.lang.c++.moderated/browse_frm/thread/97… AFAIU, a swapping assignment operator taking the parameter by const ref adheres to the strong exception safety guarantee, whereas the one taking the parameter by value fulfills the nothrow guarantee. Not sure how practical and/or relevant the difference in this context is, though. Is my observation above correct? Best Regards, Gevorg

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[review] Dataflow Review starts today, September 1st
by jarvi＠cs.tamu.edu 11 Sep '08

11 Sep '08

The review of Stjepan Rajko's Dataflow library starts today, September 1st, and will run until September 10th. --------------------------------------------------------- Description of the library: Dataflow is a generic library for dataflow programming. Dataflow programs can typically be expressed as a graph in which vertices represent components that process data, and edges represent the flow of data between the components. As such, dataflow programs can be easily reconfigured by changing the components and/or the connections. This review focuses on the Dataflow.Signals layer of the library. For its data transport mechanism, Dataflow.Signals uses Boost.Signals which can be used to make lasting dataflow connections based on function calls. Dataflow.Signals provides the following to facilitate signals-based dataflow networks: * A number of useful general-purpose components, and building blocks for implementing new components. * Various free functions and operators for connecting and using components. The library documentation provides some concrete examples of how Dataflow.Signals layer can be used. Some examples are: * Implementing distributed dataflow applications using Dataflow.Signals and Boost.Asio * An image processing network using Dataflow.Signals and Boost.GIL * A GUI dataflow editor (located in the Dataflow.Blueprint documentation) While the Dataflow library contains other layers, only the Dataflow.Signals layer is ready for review. Reviewers are welcome to provide feedback for any part of the library, but please be aware that the documentation and implementation for the other layers may be lacking (for example, there is the generic support layer, which provides concepts applicable to different dataflow frameworks, and can be used to develop generic dataflow code, as well as the Dataflow.Blueprint layer which provides run-time reflection and modeling of dataflow networks in a Boost Graph Library graph for any dataflow framework with implemented Dataflow library support). For the time being, please consider these other layers as implementation details or proof-of-concept examples, as appropriate. The library is accessible as a tarball at: http://www.boostpro.com/vault/index.php?&directory=Dataflow The documentation can be accessed here: http://www.dancinghacker.com/code/dataflow/ The documentation particular to the Dataflow.Signals layer under review: http://www.dancinghacker.com/code/dataflow/dataflow/signals.html Dataflow depends on many existing Boost libraries, such as Fusion and MPL. The Dataflow.Signals layer builds functionality over Boost.Signals. The Dataflow library has been tested using a recent version of the Boost trunk, as well as the 1.35 release. Tests and examples have been built successfuly on OS X (GCC 4.0, 4.2), Linux (GCC 4.2), and Windows (MSVC 8.0 and to some degree MinGW GCC 4.2). --------------------------------------------------------- --------------------------------------------------------- Questions you may want to answer in your review: - 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? In particular, please remember to answer the following question explicitly: - Do you think the library should be accepted as a Boost library? Jaakko Järvi Review Manager

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[exception] library update
by Emil Dotchevski 10 Sep '08

10 Sep '08

I've finished a major refactoring of the Exception library: 1) Thanks to Peter Dimov's boost/detail/sp_typeinfo.hpp, it now works with or without RTTI support. 2) I would like to thank Dave and Robert for complaining about the added weight to boost/throw_exception.hpp. I managed to reduce that cost to less than 400 lines total, all contained in boost/exception/exception.hpp which now does not #include anything (not even standard headers.) If there are more concerns about this issue, let's discuss them now. The latest documentation can be viewed at http://svn.boost.org/svn/boost/trunk/libs/exception/doc/boost-exception.html. Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode

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shared_ptr/shared_count and the cost of use counter allocation
by Hendrik Schober 10 Sep '08

10 Sep '08

Hi, I have taken the task to replace a proprietary smart pointer (a fork of an earlier 'shared_ptr' variant) used in a library used for rendering of 3D scenes by the boost's current 'shared_ptr'. The reason is that I have found a couple of syntactic problems with the proprietary smart pointer that 'shared_ptr' doesn't have. While I succeeded syntactically, in certain performance tests the proprietary smart pointer performs about 20 times better than 'shared_ptr'. It seems that this is caused by the allocation of the use counter. For the proprietary smart pointer this allocation can be tweaked by passing allocators as template arguments, while 'shared_ptr' seems not to allow this. I have yet to find out what that performance difference means for real projects, but according to those familiar with the library the reason the allocators where introduced is that there's code that very extensively creates and destroys smart pointers which suffered badly from allocation costs. Is there a way for me to tweak 'shared_ptr's performance other than by again forking into a proprietary smart pointer and introducing allocators for that one? or is there any interest in the boost community for doing this? Thanks, Schobi

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[thread_pool] Dependencies between tasks
by vicente.botet 10 Sep '08

10 Sep '08

Hi, the tread_pool pattern is very useful to improve parallelism. But sometimes we need to constraint this parallelism, for example when several task are related to the same 'instance' it could be safer to sequence them. Is there a mechanism that allows to do thinks like that on the thread_pool library? Best, Vicente

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boost graph: How to add existing subgraphs to the root graph and how to use boost::write_graphviz with subgraphs?
by Lisa Wilhelm 10 Sep '08

10 Sep '08

Hi, I am a newbie in using boost libraries and template programming, and I try to get familiar with the graph library at the moment. My first problem is, that I want to create subgrahps in "sub-functions" and create the whole graph out of these subgraphs in the calling function. I tried to create the subgraph in the calling function and pass it to the sub-function, but then, the new vertices were added to the root-graph and not to the subgraph. I solved this in the calling-function with adding all the new vertices and their edges again to the subgraph. Is there a better way to do that? My second problem is just as mentioned in the subject line. How to use boost::write_graphviz to print out subgraphs? It works for "normal" graphs but not for subgraphs. I hope this is the right place to ask these questions. Thanks for your answers. Lisa __________________________________________________ Do You Yahoo!? Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz gegen Massenmails. http://mail.yahoo.com __________________________________________________ Do You Yahoo!? Sie sind Spam leid? Yahoo! Mail verfügt über einen herausragenden Schutz gegen Massenmails. http://mail.yahoo.com

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Any interest in a Simple Thread Pool Library?
by Koushik Biswas 10 Sep '08

10 Sep '08

Hi, I am a new subscriber to boost mailing list, though I am a long time boost user. Recently, I needed a simple thread pool for my application, but did not find anything on Boost. I went ahead and developed my own. I believe that with some modifications to make it more generic, it will be a valuable addition to Boost. Following the guidelines specified in "Boost Library Submission Process" page, I am trying to gauge the interest. Synopsis: 1. Will be header only. User will derive from class "ThreadPoolJob" and override its DoJob() method with any action he wants the thread pool to perform. 2. User will instantiate an object of the Pool (can mention initial size), and simply call SubmitJob() with the pointer of an instance of his derived Thread Pool Job class - and the job will be get done. 3. In my current version, a job submission simply accepts the pointer to a new job class, hence the user has to wait until the job is done and then needs to clean up the memory. In the final library, I will take ownership of the memory while accepting a submitted job by using smart pointers. 4. Features: Dynamic shrinking/ expansion of the pool, ability to assign priorities to jobs, schedule future job execution, etc. are ion the roadmap - though I do not need any of these for my own application, the design is generic enough to add these features. Can somebody guide me to the next steps if approved? I could not log in to the boost vault with my mailing list user name and password. Do I need to create a new set? Thanks & Regards, Koushik Biswas Principal Technical Yahoo, Yahoo! Inc.

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boost::throw_exception / exception library update
by Emil Dotchevski 09 Sep '08

09 Sep '08

This is a repost of my original message, with a better subject line as suggested by Felipe, to perhaps attract more readers for this important discussion. Here is a link to the original thread: http://www.nabble.com/-exception--library-update-tt19377623.html Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode On Mon, Sep 8, 2008 at 10:59 AM, Emil Dotchevski <emil(a)revergestudios.com> wrote: > I've finished a major refactoring of the Exception library: > > 1) Thanks to Peter Dimov's boost/detail/sp_typeinfo.hpp, it now works > with or without RTTI support. > > 2) I would like to thank Dave and Robert for complaining about the > added weight to boost/throw_exception.hpp. I managed to reduce that > cost to less than 400 lines total, all contained in > boost/exception/exception.hpp which now does not #include anything > (not even standard headers.) If there are more concerns about this > issue, let's discuss them now. > > The latest documentation can be viewed at > http://svn.boost.org/svn/boost/trunk/libs/exception/doc/boost-exception.html.

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[multi_index_container] Compiling the examples
by Robert Jones 09 Sep '08

09 Sep '08

Trying to multi_index_container I'm getting these compile errors. Apart from #include <string> and using namespace boost this lifted verbatim from the example documentation. #include <string> struct employee { int id; std::string name; employee(int id,const std::string& name):id(id),name(name){} bool operator<(const employee& e)const{return id<e.id;} }; #include <boost/multi_index_container.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/identity.hpp> #include <boost/multi_index/member.hpp> using namespace boost; // define a multiply indexed set with indices by id and name typedef multi_index_container< employee, indexed_by< // sort by employee::operator< ordered_unique<identity<employee> >, // sort by less<string> on name ordered_non_unique<member<employee,std::string,&employee::name> > > > employee_set; My error is multi.cpp:23: error: `indexed_by' was not declared in this scope multi.cpp:25: error: `ordered_unique' was not declared in this scope multi.cpp:25: error: `identity' was not declared in this scope multi.cpp:25: error: template argument 2 is invalid multi.cpp:25: error: expected unqualified-id before '>' token multi.cpp:25: error: expected `,' or `;' before '>' token I'm using Boost 1.36 and gcc 3.4.4 (maybe this too old?). Can anyone tell me what I'm doing wrong? Thanks, Rob. -- ACCU - Professionalism in programming - http://www.accu.org

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[multi_index_container] push_back?
by Robert Jones 09 Sep '08

09 Sep '08

Still having a little teething trouble with multi_index_container. This code, #include <string> #include <boost/multi_index_container.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/identity.hpp> #include <boost/multi_index/member.hpp> using namespace boost; using namespace boost :: multi_index; struct Employee { int id; std :: string name; }; bool operator < ( Employee const & l, Employee const & r ) { return l.id < r.id; } int main( ) { typedef multi_index_container< Employee, indexed_by< ordered_unique<identity<Employee> >, ordered_non_unique<member<Employee, std :: string, & Employee :: name> > > > EmployeeSet; Employee employees[ ] = { { 1, "Adam" }, { 2, "Craig" }, { 3, "Brian" }, { 4, "Dave" }, }; // EmployeeSet eSet( employees, employees + sizeof( employees ) / sizeof( Employee ) ); EmployeeSet eSet; std :: copy( employees, employees + sizeof( employees ) / sizeof( Employee ), std :: back_inserter( eSet ) ); return 0; } Gives me an error stating there is no push_back method on the container. /usr/lib/gcc/i686-pc-cygwin/3.4.4/include/c++/bits/stl_iterator.h:364: error: 'class boost::multi_index::multi_index_con tainer<Employee, boost::multi_index::indexed_by<boost::multi_index::ordered_unique<boost::multi_index::identity<Employee >, mpl_::na, mpl_::na>, boost::multi_index::ordered_non_unique<boost::multi_index::member<Employee, std::string, &Employ ee::name>, mpl_::na, mpl_::na>, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na , mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>, std::allocator<Employee> >' has no member named 'push_back' is there something I'm missing out? Thanks, Rob.

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