December 2011 - Boost - lists.boost.org

[thread] feature request priority
by Vicente J. Botet Escriba 04 Jan '12

04 Jan '12

Hi, here they are a list of 26 feature requests for Boost.Thread. The features are classified as high, middle and low cost (form my point of view of course) I would like to know which features would you like to find on the next release. Please could you choose 3 features and if possible one for each category, the idea been to provide 1 high, 1 middle and 2 low features for the next release. High #2100 <https://svn.boost.org/trac/boost/ticket/2100> thread fails to compile with -fno-exceptions <https://svn.boost.org/trac/boost/ticket/2100> #6195 <https://svn.boost.org/trac/boost/ticket/6195> Provide the standard time related interface using Boost.Chrono <https://svn.boost.org/trac/boost/ticket/6195> #6217 <https://svn.boost.org/trac/boost/ticket/6217> Make uniform Boost.Thread and Boost.Interprocess synchronization interface <https://svn.boost.org/trac/boost/ticket/6217> #6230 <https://svn.boost.org/trac/boost/ticket/6230> Follows the exception reporting mechanism as defined in the c++11 <https://svn.boost.org/trac/boost/ticket/6230> #5150 <https://svn.boost.org/trac/boost/ticket/5150> boost::thread does not print or return the error value when creating a thread fails. <https://svn.boost.org/trac/boost/ticket/5150> #6194 <https://svn.boost.org/trac/boost/ticket/6194> Adapt to Boost.Move <https://svn.boost.org/trac/boost/ticket/6194> Middle #2741 <https://svn.boost.org/trac/boost/ticket/2741> proposal to manage portable and non portable thread attributes <https://svn.boost.org/trac/boost/ticket/2741> #2880 <https://svn.boost.org/trac/boost/ticket/2880> Request for Thread scheduler support for boost .. <https://svn.boost.org/trac/boost/ticket/2880> #3696 <https://svn.boost.org/trac/boost/ticket/3696> Boost Thread library lacks any way to set priority of threads <https://svn.boost.org/trac/boost/ticket/3696> #4710 <https://svn.boost.org/trac/boost/ticket/4710> Missing async() <https://svn.boost.org/trac/boost/ticket/4710> #4725 <https://svn.boost.org/trac/boost/ticket/4725> Synchronization and shared mutex's Get total_count <https://svn.boost.org/trac/boost/ticket/4725> #5173 <https://svn.boost.org/trac/boost/ticket/5173> boost::this_thread::get_id is very slow <https://svn.boost.org/trac/boost/ticket/5173> #5425 <https://svn.boost.org/trac/boost/ticket/5425> This patch will allow the user to obtain the users thread pointer from a thread group. <https://svn.boost.org/trac/boost/ticket/5425> #5956 <https://svn.boost.org/trac/boost/ticket/5956> Add optional stack_size argument to thread::start_thread() <https://svn.boost.org/trac/boost/ticket/5956> #6227 <https://svn.boost.org/trac/boost/ticket/6227> Use of variadic templates on Generic Locking Algorithms on compilers providing them <https://svn.boost.org/trac/boost/ticket/6227> #6228 <https://svn.boost.org/trac/boost/ticket/6228> Add promise and futures constructor with allocator following the standard c++11 <https://svn.boost.org/trac/boost/ticket/6228> #6229 <https://svn.boost.org/trac/boost/ticket/6229> Rename the unique_future to future following the c++11 <https://svn.boost.org/trac/boost/ticket/6229> Low #1789 <https://svn.boost.org/trac/boost/ticket/1789> thread_group not passing variables <https://svn.boost.org/trac/boost/ticket/1789> #1850 <https://svn.boost.org/trac/boost/ticket/1850> request for unlock_guard (and/or unique_unlock) to compliment lock_guard/unique_lock <https://svn.boost.org/trac/boost/ticket/1850> #2361 <https://svn.boost.org/trac/boost/ticket/2361> thread_specific_ptr: nature of the key, complexity and rationale <https://svn.boost.org/trac/boost/ticket/2361> #2637 <https://svn.boost.org/trac/boost/ticket/2637> shared mutex lock <https://svn.boost.org/trac/boost/ticket/2637> #3567 <https://svn.boost.org/trac/boost/ticket/3567> Request for shared_lock_guard <https://svn.boost.org/trac/boost/ticket/3567> #6224 <https://svn.boost.org/trac/boost/ticket/6224> Add the use of standard noexcept on compilers supporting them <https://svn.boost.org/trac/boost/ticket/6224> #6225 <https://svn.boost.org/trac/boost/ticket/6225> Add the use of standard =delete defaulted operations on compilers supporting them <https://svn.boost.org/trac/boost/ticket/6225> #6226 <https://svn.boost.org/trac/boost/ticket/6226> add explicit bool conversion from locks <https://svn.boost.org/trac/boost/ticket/6226> #6231 <https://svn.boost.org/trac/boost/ticket/6231> Add BasicLockable requirements in the documentation to follow c++11 <https://svn.boost.org/trac/boost/ticket/6231> Patches are welcome for any feature. Note that a feature that have all the needed patches, code, doc and tests could be included soon. Thanks in advance, Vicente

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[thread] Reducing the number of open tickets.
by Vicente J. Botet Escriba 03 Jan '12

03 Jan '12

Hi, I have committed the following tickets in trunk. Fixed Bugs: * [@http://svn.boost.org/trac/boost/ticket/2639 #2639] documentation should be extended(defer_lock, try_to_lock, ...). * [@http://svn.boost.org/trac/boost/ticket/3762 #3762] Thread can't be compiled with winscw (Codewarrior by Nokia). * [@http://svn.boost.org/trac/boost/ticket/3885 #3885] document about mix usage of boost.thread and native thread api. * [@http://svn.boost.org/trac/boost/ticket/3975 #3975] Incorrect precondition for promise::set_wait_callback(). * [@http://svn.boost.org/trac/boost/ticket/4480 #4480] OpenVMS patches for compiler issues workarounds. * [@http://svn.boost.org/trac/boost/ticket/4819 #4819] boost.thread's documentation misprints. * [@http://svn.boost.org/trac/boost/ticket/5423 #5423] thread issues with C++0x. * [@http://svn.boost.org/trac/boost/ticket/5739 #5739] set-but-not-used warnings with gcc-4.6 * [@http://svn.boost.org/trac/boost/ticket/6168 #6168] recursive_mutex is using wrong config symbol (possible typo). * [@http://svn.boost.org/trac/boost/ticket/6200 #6200] patch to have condition_variable and mutex error better handle EINTR. These are tickets with a simple solution or that had associated a complete patch or a clear solution. Anthony I would prefer that you do the merge so that you can check what goes on the release version. I have not closed the tickets. These tickets have just release 1.49 as Milestone. Please, close them when you merge to release. There were 113 tickets two days ago. There are now 114 tickets associated to Boost.Thread. I have closed some duplicates, but some news tickets have been created since. I would like to reduce by 10% the number of tickets every month. I encourage the Boost users that have created tickets for Boost to provide a clear an complete patch when possible so that we can reduce together the number of tickets associated to this Boost library and make it more portable/usable. Don't forget to provide tests that make evident the bug, or to add doc when you are proposing a anew feature. There are a lot of tickets associated to move semantics emulation. I have created a ticket to adapt Boost.Thread to Boost.Move hoping most of these bugs will be solved. As posted in another thread there is already a patch using Boost.Move that could be a good starting point. Of course the help offered by Ion will be too much appreciated. I have created another to adapt the interface to Boost.Chrono, but I will prefer to take care of this once the one for Boost.Move adaptation is committed, as the chance of collisions is big. On the mean time I will continue with some tickets specific to Windows platform. Best, Vicente

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How to get involved ?
by Vijeenrosh PW Vijeen 03 Jan '12

03 Jan '12

Good Morning , My name is Vijeenrosh P.W . Iam an Computer Science and Engineering student . I have knowledge in c,c++,python and linux , and an mind to extend my areas of knowledge. Recently while passing through the list of GSOC accepted organizations I met with boost libraries . it fits me since I have C++ && programming knowledge and is ready to work . I would like to know how to begin to contribute to the project . Where to begin . or is there any warm up excersices to get passed ? -- Vijeenrosh P.W CSE S3 blog : www.BlackJackVijeen.blogspot.com

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RFC: Multiprecision arithmetic library
by John Maddock 03 Jan '12

03 Jan '12

Folks, I'd like to get some feedback on a multiprecision arithmetic library I've been preparing for possible Boost inclusion. The code is in the sandbox under the "big_number" directory. Docs can be viewed online here: http://svn.boost.org/svn/boost/sandbox/big_number/libs/multiprecision/doc/h… The main features are: * A generic front-end that's capable of wrapping almost any type that's a "number". The front end is expression template enabled and handles all the expression optimization and code reduction. For example it's possible to evaluate a polynomial using Horner's rule without a single temporary variable being created. * A series of backends that need only provide a reduced interface and set of operations, implement the actual arithmetic, currently supported backends are: Integer Types ~~~~~~~~~ 1/ GMP (MPZ). 2/ libtommath. Rational Types ~~~~~~~~~~ 1/ GMP (MPQ). [ But note that the integer types can also be used as template aruments to Boost.Rational ] Floating Point Types ~~~~~~~~~~~~~~ 1/ GMP (MPF) 2/ MPFR 3/ cpp_float - an all C++ Boost-licensed backend based on Christopher Kormanyos' e_float code. [ Note these three types are fully compatible with Boost.Math Trunk - so you get full standard library plus special function support ] There's still a bunch to do, but I'd like to see what folks think, and where the main priorities should be before submission. Thanks in advance, John.

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boost modularisation status?
by Robert Ramey 02 Jan '12

02 Jan '12

https://svn.boost.org/trac/boost/wiki/CMakeModularizationStatus hasn't been modified in 3 years. Also, when I peruse my local copy of the release tree, I don't see what I expect to see according to https://svn.boost.org/trac/boost/wiki/CMakeModularizeLibrary That is, I expect to seem include inside of the libraries at boost/libs/tr1/include - I don't see this. What is the current status of this? Robert Ramey

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[Graph] LEDA adapter - concept check VertexListGraph fails
by Jens Müller 02 Jan '12

02 Jan '12

Hi everyone, when running the tests for Graph, the first concept check in leda_graph_cc.cpp fails: gcc.compile.c++ ../../../bin.v2/libs/graph/test/leda_graph_cc.test/gcc-4.6.1/debug/leda_graph_cc.o In file included from leda_graph_cc.cpp:9:0: ../../../boost/graph/graph_concepts.hpp: In destructor 'boost::concepts::VertexListGraph<G>::~VertexListGraph() [with G = leda::GRAPH<int, int>]': ../../../boost/graph/graph_concepts.hpp:168:1: instantiated from 'static void boost::concepts::requirement<boost::concepts::failed************ Model::************>::failed() [with Model = boost::concepts::VertexListGraphConcept<leda::GRAPH<int, int> >]' leda_graph_cc.cpp:21:5: instantiated from here ../../../boost/graph/graph_concepts.hpp:189:9: error: no matching function for call to 'vertices(leda::GRAPH<int, int>&)' ../../../boost/graph/graph_concepts.hpp:189:9: note: candidate is: ../../../boost/graph/graph_concepts.hpp:45:48: note: template<class T> typename T::ThereReallyIsNoMemberByThisNameInT boost::vertices(const T&) (among some further errors, but I'd like to ask just about this one now) Apparently it cannot find a vertices() function: ../../../boost/graph/graph_concepts.hpp:189:9: error: no matching function for call to 'vertices(leda::GRAPH<int, int>&)' But there is one in leda_graph.hpp: template <class vtype, class etype> inline std::pair< typename graph_traits< leda::GRAPH<vtype,etype> >::vertex_iterator, typename graph_traits< leda::GRAPH<vtype,etype> >::vertex_iterator > vertices(const leda::GRAPH<vtype,etype>& g) { typedef typename graph_traits< leda::GRAPH<vtype,etype> >::vertex_iterator Iter; return std::make_pair( Iter(g.first_node(),&g), Iter(0,&g) ); } So, can someone enlighten me why it isn't found? Has it something to do with #ifdef BOOST_VECTOR_AS_GRAPH_GRAPH_ADL_HACK // dwa 2003/7/11 -- This clearly shouldn't be necessary, but if // you want to use vector_as_graph, it is! I'm sure the graph // library leaves these out all over the place. Probably a // redesign involving specializing a template with a static // member function is in order :( using boost::vertices; #endif ? Best regards, Jens

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Many Boost.Test unit tests fail
by Barend Gehrels 02 Jan '12

02 Jan '12

Hi, Since today or yesterday, many regression tests fail. http://www.boost.org/development/tests/trunk/developer/summary.html I believe on platforms that are recently added, at last on platforms that were not present at December 17. 1) on clang/darwin, message ../boost/test/tools/assertion.hpp:278:21: error: no member named 'forward' in namespace 'std' 2) on clang/linux, message /usr/bin/ld: skipping incompatible /sierra/Sntools/extras/compilers/gcc-4.4.4/lib/libstdc++.so when searching for -lstdc++ We have these errors in Boost.Geometry but I also noticed them in many other libraries. Regards, Barend

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[filesystem] path thread safety fix impact on POSIX systems
by Beman Dawes 01 Jan '12

01 Jan '12

Class path locale initialization has suffered from a data race for several releases. See https://svn.boost.org/trac/boost/ticket/6320 for an example of code that suffers as a result. The problem was introduced when locale initialization was changed from namespace scope initialization to function scope initialization. For Windows and Mac OS X, the fix is simply to change back to namespace scope initialization. For non-BSD based POSIX systems such as Linux, the problem is more complex. These system need std::locale(""), "the locale-specific native environment". Considerations: * std::locale("") will throw if environmental variables are configured incorrectly. For example, setting LANG=foo on my Ubuntu system causes std::locale("") to throw. * std::locale("") is only needed if conversions between wide and narrow character paths occur in the program, so it would be unfortunate to have programs throw that don't actually do any such conversion. * With GCC, std::locale("") at namespace scope will throw before main() has started! That prevents catching the exception in the user code, and was what led to moving the initialization to a function scope static. Initialization as a function scope static also meant that the exception only occurred if user code actually performed wide - narrow conversions. I can see two possible fixes: (A) Use function scope locale initialization, using boost/detail/lightweight_mutex.hpp to prevent data races. (B) Use namespace scope locale initialization, defaulting the codecvt facet to UTF-8 if std::locale("") throws. The advantage of (B) is that path always initializes without throwing, and that's what users seem to expect. The initialization is correct for all those whose environments are configured correctly, and for those uses who want UTF-8 even if their environments are misconfigured. The POSIX users who prefer an exception on a misconfigured environment can always add a std::locale("") at the start of main(). Comments or opinions? --Beman

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Re: [boost] matrix and vector iterators
by Larry Evans 31 Dec '11

31 Dec '11

On 06/12/01 14:50, David Abrahams wrote: > > ----- Original Message ----- > From: "Larry Evans" <jcampbell3(a)prodigy.net> > > >> David Abrahams wrote: >> >>> One problem with this is that it requires much more of the iterator in > some >>> cases than it otherwise might. In an array stored as vectors of vectors >>> of... vectors, each iterator would need to have references to all of the >>> containing vectors. >> >> Couldn't the iterator just contain a vector of indices of length == rank, >> and a pointer to the vector of vectors of... vectors (VofV), and then just > index into >> the VofV with the vector of indices. > > When you start talking about iterators containing vectors, I get worried. > >> I guess bad thing about that is that it takes longer. > > That's putting it mildly. Iterators should be lightweight. > > -Dave > > Another type of iterator which essentially flattens a multi-dimensional array and *may* be more lightweight is implemented here: http://svn.boost.org/svn/boost/sandbox/variadic_templates/sandbox/stepper/b… and demonstrated here: http://svn.boost.org/svn/boost/sandbox/variadic_templates/sandbox/stepper/l… A more realistic demonstration is in the Partial Differential Equation example here: http://svn.boost.org/svn/boost/sandbox/variadic_templates/sandbox/stepper/l… which uses an axes rotation feature that, IIUC, was requested by Petros here: http://article.gmane.org/gmane.comp.lib.boost.user/68017 Its also used here: http://svn.boost.org/svn/boost/sandbox/variadic_templates/sandbox/stepper/l… which is probably a bit easier to follow than the array_dyn.diff_pde.cpp one ;) I've done no benchmarks; hence, I can't say how lightweight it is; however, since all it does is keep a stack of indices in a data structure instead of on the stack, I would think it wouldn't be that much more heavyweight than simply a nested for loop nested N deep where N is the array dimensionality. BTW, Petros, in a private email to me, has indicated he has some other method for solving the rotated axes problem; however, I've no idea if that's more or less lightweight than this one. -regards, Larry I've run no benchmarks to show how lightweight it may be. Petros, in a private email to me, says he has another way of

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Re: [boost] Comparison of serialization results
by Brian Wood 31 Dec '11

31 Dec '11

Dave Abrahams: > > No post-hock marshalling? You should be able to add marshalling to a > class without modifying its declaration. > If a class is popular enough, I often do. For example, the C++ Middleware Writer (CMW) has support for the standard containers, std::complex, multi_index_container, stable_vector and others. [...] > > No argument; I'm just sayin'. I don't have to go to any great lengths to find tests where the performance of executables that use Boost Serialization lags behind CMW based executables. I just think up a test and write it. The tests are quite basic. > > That's a fundamentally intrusive design; being able to add serialization > non-intrusively was a major design goal for Boost.Serialization. I see. One thing I didn't mention yesterday is support for stream- based constructors: class Base { template <typename R> explicit Base (ReceiveBufferFile<R>& buf); ... }; Does the Boost Serialization library have support for that? Cheers, Brian Wood Ebenezer Enterprises http://webEbenezer.net

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