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[config][mpl][type_traits][integer] BOOST_STATIC_CONSTANT should use constexpr
by Vicente J. Botet Escriba 22 Apr '13

22 Apr '13

Hi, BOOST_STATIC_CONSTANT could be improved to make use of constexpr. This is needed for instance to make integral_constant compliant with C++11. The patch consists in changing const by BOOST_CONSTEXPR_OR_CONST in boost/config/suffix.hpp // BOOST_STATIC_CONSTANT workaround --------------------------------------- // // On compilers which don't allow in-class initialization of static integral // constant members, we must use enums as a workaround if we want the constants // to be available at compile-time. This macro gives us a convenient way to // declare such constants. # ifdef BOOST_NO_INCLASS_MEMBER_INITIALIZATION # define BOOST_STATIC_CONSTANT(type, assignment) enum { assignment } # else # define BOOST_STATIC_CONSTANT(type, assignment) static *BOOST_CONSTEXPR_OR_CONST* type assignment # endif and in each out of line static constant definition as in template <int b1, int b2> bool *BOOST_CONSTEXPR_OR_CONST* ice_eq<b1,b2>::value; The main problem is that this is a *breaking change*: the list of concerned libraries is quite big (mpl, type_traits/integer_traits, ...) and users of BOOST_STATIC_CONSTANT would need to make this modification also. An alternative is to define a BOOST_STATIC_CONSTANT_11 that includes this modification and update the Boost libraries that could make use of the new macro without introducing a breaking change. Library providing a template class containing a field with such a change that can be specialized by the user would need to either announce a breaking change or just don't use the new macro. While this mean more changes the backward compatibility can be mastered. What do you think, it is worth try to fixing this? Best, Vicente

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GSOC - Boost.SQL and Boost.Thread interest
by Guillaume Nuel 22 Apr '13

22 Apr '13

Hi Boost C++ Team ! My name is Guillaume NUEL. I'm a French student in computer security (fourth year in computer science). I'm actually making a game witch uses Boost (Thread, Signal,...). I also use CouchBase for database. I really would like mixing my game development and Boost development. My project proposal Idea : I'm mainly interesting in adding a new module: Boost.SQL for managing database: MySQL, Couchbase, … If the project proposal is not suitable, I have others interests. I would also be interesting in adding new functions to Thread abilities. So I am interested in the following topics : - Boost.Thread/SyncQueue: Provide boost::sync_bounded/unbounded_queue implementations base on the C++ Concurrent Queues proposal. Trying an adaptation of the Boost.LockFree queues to follow the same interface. - Boost.Thread/ThreadPool:Provide a boost::thread_pool class scheduling arbitrary functions based on Toward Boost Async 0.2 and extend the boost::async function to manage with this new class. Projects mentored by Vicente J. Botet Escriba I'm an expert in C++ and I have good skills in OpenMP and Cuda ( GPU ) and so in parallelization of code. Homepage: http://immmortal-pc.info/Boost.html My CV is available at http://immortal-pc.info/cv.html Thank you for taking the time to read my e-mail, I look forward to receive a response from you. With regards, NUEL Guillaume

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GSoC: More mentors?
by Boris Schaeling 22 Apr '13

22 Apr '13

From Monday on students can apply for GSoC projects. Mentors can already apply at <https://google-melange.appspot.com/gsoc/homepage/google/gsoc2013>. So far we have four possible mentors (for uBLAS, odeint, graph and benchmark). Are there others who would like to mentor? Then please pick a project from <https://svn.boost.org/trac/boost/wiki/SoC2013> or propose your own (like I did a few days ago: <http://article.gmane.org/gmane.comp.lib.boost.devel/240251>). Applying as a mentor doesn't mean that you must mentor a student. Among others it all depends on if and how many student applications we will receive. But having a few more mentors just in case would be nice. :) Thank you, Boris

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media > audio project (gsoc or future boost)
by adrien courdavault 22 Apr '13

22 Apr '13

Hi everyone. I read the project list for the GSOC 2013 and in Ideas I've seen the mention of Audio. I would like to know who is interested in this and if someone could give some details about this line : 'Audio library (OpenAL/FMOD/etc)' see here :https://svn.boost.org/trac/boost/wiki/SoC2013#Media I would like to know if this might be related to this: http://comments.gmane.org/gmane.comp.lang.c%2B%2B.isocpp.proposals/310 Thank you in advance. Adrien

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Writing timer output to file
by Mohamed Nemri 22 Apr '13

22 Apr '13

Hi, I want customize boost::timer::auto_cpu_timer to put results in a logging stream(file, console,...). What is the best way to do that? Thanks --

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[GSoC] Boost.Multiprecision project
by Jyotesh Choudhari 22 Apr '13

22 Apr '13

Hello, My name is Jyotesh Choudhari and I am from India. I am pursuing my Masters in Computer Science and Technology from Indian Institute of Technology (IIT) Bombay. I went through the ideas page for GSoc 2013 and would like to work on Boost.Multiprecision (cpp_bin_float) project. Looking at the project description, I think I have understood what needs to be implemented in this project. I have also gone through the current code cpp_bin_float.hpp and I have understood some part of it. I want to know how detailed should my proposal be? What details should I include in my proposal? What should be the deliverables for the project? Thanking you. Regards, Jyotesh Choudhari

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[GSoC] Boost.multiprecision project
by Flórián Deé 22 Apr '13

22 Apr '13

Hello, I'm Florián Deé from Hungary, studying at Budapest University of Technology and Economics. I'm really interested in the Boost.Multiprecision project for GSoC 2013. A little background on myself, I'm an undergraduate software engineering student mostly into C and C++, with interests in low level programming and maths. I'm currently working on a project as an outsider member of the dorm's Coder team (a poker framework for AIs), and I'm also a "consultant" for students with their C/C++/Maths assignments (mostly calculus and linear algebra). As a result, I don't really have much free time till the exams, but I've planned, seen, written and debugged lots of different projects with different coding styles. Going through the project description, I think my skill set and interests would fit in nicely, with the exception of fast Fourier transforms, which I'm only mildly familiar with, but I'd gladly read any needed extra material till summer. So I kindly seek your guidance to help me go about my application for the GSoC 2013. Looking forward to your reply. Regards, Flórián

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[ublas] bugfix for matrix operation /
by Mario Mulansky 22 Apr '13

22 Apr '13

Hi, I wanted to add an elementwise divide operations for ublas matrices using operator / Unfortunately, there is operator/ defined for matrix and integral types which hides any other operator definition (matrix_expression.hpp l. 3388) and thus makes it impossible to add this functionality. I would like to add an enable_if statement there that checks if the second argument is convertible to matrix::value_type, as is done for other operators. Who would be responsible for this small change? I can provide the according patch, it's almost trivial. Mario

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[gsoc-2013] Physics Library Abstraction Layer
by Preston Hamlin 22 Apr '13

22 Apr '13

I am working on putting together a draft proposal for the project. Is there a preferred format desired? I was going to use a PDF since they are quite portable. I am somewhat confused as to the scope of the project, due to the previous posts in this thread. Is the library to be built upon a specific physics library (PhysX for instance) by utilizing existing code in the respective SDK to abstract away much of the object management? Or is it meant to be built from the ground up to create generic objects, which can then be translated into an arbitrary format for an existing library? Thank-you, -Preston

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library to support async/await pattern
by Valentin Milea 21 Apr '13

21 Apr '13

Is there interest for a coroutine-based library to make asynchronous APIs easier to deal with? Typically, for each task there is cruft: chaining callbacks, managing intermediate state and error codes (since exceptions don't fit this model). The code flow get inverted and becomes difficult to follow. Recent versions of F# and C# solve this problem. They implement an await operator that effectively suspends the executing method until a task completes. The compiler takes care of transforming subsequent code into a continuation. Everything runs on the main thread, with asynchronous methods spending most time awaiting. N3328 proposes resumable functions of this kind in C++. For an immediate solution we could leverage the Boost.Context/Coroutine library. The resulting code may look like this: try { task = do_a_async(...) // yield until task done task.await(); } catch (const some_exception& e) { // exceptions arrive in awaiting context } // normal code flow for (auto& task : tasks1) { task.await(); } taskAny = await_any(tasks2); taskAny.await(); ... There needs to be a representation for Awaitable tasks (similar to std::future but non-blocking). The other requirement is to have a Scheduler (run loop) in order to weave between coroutines. Benefits: - normal code flow: plain conditionals, loops, exceptions, RAII - algorithm state tracked on coroutine stack - async tasks are composable - any async API can be wrapped Cons: - must wrap async APIs (e.g. Boost.Asio) - needs std::exception_ptr to dispatch exceptions - stackful coroutines are sometimes difficult to debug I wrote an open-source library that does this: https://github.com/vmilea/CppAwait. It's far from Boost style but the concept looks sane. For a comparison between async patterns please see: https://github.com/vmilea/CppAwait/blob/master/Examples/ex_stockClient.cpp Making a Boost version would involve serious redesign. So is this worth pursuing? Thanks!

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