May 2013 - Boost - lists.preview.boost.org

Algorithmic Skeletons, Parallelism Patterns & Actors
by Suminda Dharmasena 28 May '13

28 May '13

Hi, Is it possible to introduce Algorithmic Skeletons, Parallelism Patterns & Actors in Boost? Any plans for this? Suminda -- Suminda Sirinath Salpitikorala Dharmasena, B.Sc. Comp. & I.S. (Hon.) Lond., P.G.Dip. Ind. Maths. J'Pura, MIEEE, MACM, CEO Sakrīō! ▣ *Address*: 6G • 1st Lane • Pagoda Road • Nugegoda 10250 • Sri Lanka. ▣ *Mobile* : +94-(0)711007945 ▣ *Tele*: +94-(0)11-5 864614 / 5 875614 / 2 825908 ▣ *Web *: http://www.sakrio.com ▣ This email is subjected to the email Terms of Use and Disclaimer: http://www.sakrio.com/email-legal. Please read this first. --

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[type_erasure] compile error with gcc 4.8
by Christophe Henry 27 May '13

27 May '13

Hi Steven, the following code used to compile with older gcc versions (I just tried with 4.5 and I used the same construct with 4.7) but no more with gcc 4.8, but I don't know whether it's a gcc or type_erasure problem (or mine). The problem seems to be with rvalue refs. If I use the commented out version, it compiles fine on both compilers. Any idea? If you have no gcc 4.8, I can attach the error. Thanks, Christophe #include <iostream> #include <boost/type_erasure/any.hpp> #include <boost/type_erasure/builtin.hpp> #include <boost/type_erasure/operators.hpp> #include <boost/type_erasure/constructible.hpp> #include <boost/type_erasure/relaxed.hpp> #include <boost/type_erasure/member.hpp> #include <boost/mpl/vector.hpp> #include <boost/function.hpp> BOOST_TYPE_ERASURE_MEMBER((has_post), post); struct any_post_concept: ::boost::mpl::vector< //has_post<void(boost::function<void()>), const boost::type_erasure::_self>, has_post<void(boost::function<void()>&&), const boost::type_erasure::_self>, boost::type_erasure::relaxed, boost::type_erasure::copy_constructible<> >{} ; typedef boost::type_erasure::any<any_post_concept> any_post; struct any_impl { //void post(boost::function<void()> f)const {f();} void post(boost::function<void()> && f)const {f();} }; int main() { any_impl s; any_post p (s); boost::function<void()> f = [](){std::cout << "ok" << std::endl;}; //p.post(f); p.post(std::move(f)); return 0; }

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[thread] countdown_latch
by Michael Marcin 27 May '13

27 May '13

I recently ran across the need to spawn a thread and wait for it to finish its setup before continuing. The accepted answer seems to be using a mutex and condition variable to achieve this. However that work clutters up the code quite a bit with the implementation details. I came across Java's CountDownLatch which does basically the same work but bundles it up into a tidy package. It seems to be a fairly trivial but useful abstraction. implementation: http://codepad.org/E8kd2Eb8 usage: class widget { public: widget() : latch( 1 ) , thread_( [&]{ thread_func(); } ) { latch.wait(); } private: void setup(); void run(); void thread_func() { setup(); latch.count_down(); run(); } countdown_latch latch; std::thread thread_; };

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Proposal for a new assert macro which stores the failed values ("informative assert")
by Viktor Sehr 27 May '13

27 May '13

I'd like some opinions about this assert implementation which I'd like to propose as an update of the old BOOST_ASSERT. Basically it stores the failed values next to the expression string, instead of just the expression string: "INFORMATIVE_ASSERT(5*5 < 2*2);" "5*5 < 2*2 | 25 | 4" "INFORMATIVE_ASSERT(std::vector<int>(10).size() == std::vector<int>(12).size());" "std::vector<int>(10).size() > std::vector<int>(12).size() | 10 | 12" Notes - If the class can't be serialized, the byte-data is logged instead. - It writes the values to the expression string in order to be compliant with any assert implementations Easy to read implementation available here: https://docs.google.com/file/d/0B69BCPzak52DcnF5dmhRRno3V2M/edit?usp=sharing Modified version of BOOST_ASSERT available here: https://docs.google.com/file/d/0B69BCPzak52DZW1oX1AtREM4eVU/edit?usp=sharing /Viktor Sehr

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Documenting and checking template parameters
by Paul A. Bristow 26 May '13

26 May '13

I am just refactoring the venerable circular_buffer documentation. The docs describe the Template parameter T and specify it thus: The type of the elements stored in the circular_buffer. The T has to be SGIAssignable (SGI STL defined combination of Assignable and CopyConstructible). Moreover T has to be DefaultConstructible if supplied as a default parameter when invoking some of the circular_buffer's methods e.g. insert(iterator pos, const value_type& item = value_type()). And EqualityComparable and/or LessThanComparable if the circular_buffer will be compared with another container. This looks a bit out of date? Questions: How should a parameter like this *best* be described in documentation and enforced in software? http://www.boost.org/doc/libs/1_53_0/doc/html/Assignable.html ? http://www.boost.org/doc/libs/1_53_0/libs/concept_check/concept_check.htm ? Should these concepts be checked using BOOST_STATIC_ASSERT? Should *All* these be checked, even though not required for all uses? Suggestions welcome. Thanks Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

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[githelp] Can't clone superproject..
by Rene Rivera 26 May '13

26 May '13

Not sure if it's just because I'm using Eclipse JGit for this but I get: === Git repository clone failed. Missing unknown 57ec5d1534810090649b18c88e66a46f48cdcf1c === When I attempt to import/clone the superproject plus submodules. -- -- -- Grafik - Don't Assume Anything -- Redshift Software, Inc. - http://redshift-software.com -- rrivera/acm.org - grafik/redshift-software.com -- 102708583/icq - grafikrobot/aim - grafikrobot/yahoo

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[githelp] forwarding headers?
by legalize+jeeves＠mail.xmission.com 26 May '13

26 May '13

[Please do not mail me a copy of your followup] OK, I can recursively cloen the git repo and with a little editing of bootstrap.sh to remove the presence of '/v2', I am able to finish the bootstrap script. However, actually building libraries fails because there is no 'boost' subdirectory and presumably no forwarding headers in that directory. So how are those built? -- "The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline> The Computer Graphics Museum <http://computergraphicsmuseum.org> The Terminals Wiki <http://terminals.classiccmp.org> Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>

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[regex][config] BOOST_FALLTHROUGH not on the release branch
by Daniel James 26 May '13

26 May '13

The implementation of the new BOOST_FALLTHROUGH macro hasn't been merged to release yet, but the regex merge from yesterday included some code which uses it, so that isn't compiling now. The test results are a bit behind, so it hasn't shown up there yet.

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Boost.Thread Co-authoring
by Vicente J. Botet Escriba 26 May '13

26 May '13

Hi, I'm the main maintainer of Boost.Thread since Nov 2011. I've fixed a lot of bugs and added a lot of new features (mainly conformance with C++11, but also others). Could my name appear as co-author of Boost.Thread in http://www.boost.org/doc/libs/1_53_0/? Best, Vicente

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[trac] New component for type_erasure.
by Daniel James 25 May '13

25 May '13

Please can someone create a component for 'type_erasure', user 'steven_watanabe'? Thanks.

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