April 2014 - Boost - lists.boost.org

[algorithm] Split that appends
by Sebastian Karlsson 17 Apr '14

17 Apr '14

First of all I think it's a bit unintuitive that boost::algorithm::split swaps with target, I would've assumed it appended. The fact that it in effect clears target makes it cumbersome to incrementally split into a destination, as you need a new temporary for every call to split, and then explicitly transfer everything over to your final destination. The docs do mention the behavior as a note ( which I presume is precisely because it's a bit unintuitive ). My question then naturally becomes why does split behave like this? As changing the behavior would be a breaking change, do you think it would be unreasonable to have a split_append? Kind regards, Sebastian Karlsson

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[property_tree] xml_parser::read_xml() and write_xml() are limited to std::string keys
by Alexander Bogdashevsky 17 Apr '14

17 Apr '14

boost::property_tree::xml_parser and json_parser are hardcoded to work only with keys of std::string type. The following code will fail to compile: boost::property_tree::basic_ptree<boost::container::string, boost::container::string> pt; std::string filename("123.xml"); boost::property_tree:xml_parser::read_xml(filename, pt); I have prepared a patch that removes this limitation. Please consider pulling https://github.com/sanderbog/property_tree/commit/8af8b6bf3b65fa59792d849b5… Kind Regards, Alexander Bogdashevsky

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[math] & [random] distribution object compatibility
by Thijs van den Berg 16 Apr '14

16 Apr '14

Boost [random] has probability distribution objects for drawing random samples of those distributions. Boost [math] also has probability distributions, those provide free functions for computing properties of the distributions, like mean, pdf etc. I like the free function design of math variant e.g. it uses pdf(distribution,x) and I was wondering why this hasn’t been adopt in C++11 for <random>? To me a free function syntax like random(distribution,engine) would make sense. It would align with the fact that C++11 has added begin(container) and end(container) free functions. I think it’s a bit inconvenient to have two libs that both contain probability distributions. Especially since I’m hoping that boost/math would some day en up in the standard? One way we could integrate the two libs is by adding a random(distribution,engine) free function to the math lib which would accept both distribution objects from the random lib and the math lib. This however could stimulate users in writing less C++11 portable code. My questions are: * Why wasn’t the free function syntax adopted in C++11? Perhaps because of performance options? * Is there an effort to integrate the distributions in math and random within boost? * Are there concrete plans to add elements of math to the C++ standard? We already have <random> now, I would love more.

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clang++ isn't getting the BOOST_NO_CXX11_HDR_FUNCTIONAL flag that it needs
by Chris Cooper 16 Apr '14

16 Apr '14

Trying to build & run the regression tests for boost 1.55 on my Mac using the clang++ that comes with Xcode 5.1 ("Apple LLVM version 5.1 (clang-503.0.38) (based on LLVM 3.4svn)”), it can’t build config_test.cpp because BOOST_NO_CXX11_HDR_FUNCTIONAL isn’t set, and libs/config/test/boost_no_ccx_hdr_functional.ipp definitely doesn’t build (after renaming it to .cpp of course). If I set CXXFLAGS to "-std=c++11 -stdlib=libc++” everything is fine, but I also need a build of boost that _doesn’t_ use c++11, and it’s the non-c++-11 version that is failing. I can get around this by manually setting CXXFLAGS to “-DBOOST_NO_CXX11_HDR_FUNCTIONAL” but it seems like the correct way to do this is to add a test to boost/config/compiler/clang.hpp that tests … something… and then sets BOOST_NO_CXX11_HDR_FUNCTIONAL if appropriate. 1. Would you agree that’s the right place to set BOOST_NO_CXX11_HDR_FUNCTIONAL (when appropriate)? 2. Any suggestions on the correct test to determine whether BOOST_NO_CXX11_HDR_FUNCTIONAL is needed? It looks like the _has_feature() macro is the preferred method, but I can’t figure out which feature to check for … Thanks, Chris p.s. The text of the 3 errors (when trying to compile boost_no_cxx_hdr_functional) is exceedingly lengthy, but to summarize: usr/bin/../lib/c++/v1/__functional_base_03:962:22: error: no matching function for call to '__invoke' typedef decltype(__invoke(_VSTD::declval<_Fp>())) type; usr/bin/../lib/c++/v1/__config:496:32: note: expanded from macro 'decltype' #define decltype(x) __typeof__(x) usr/bin/../lib/c++/v1/__functional_base_03:1019:14: note: in instantiation of template class 'std::__1::__invoke_return<int &, false>' requested here typename __invoke_return<type&>::type ./boost_no_cxx_hdr_functional.ipp:22:4: note: in instantiation of template class 'std::__1::reference_wrapper<int>' requested here std::ref(i); usr/bin/../lib/c++/v1/__functional_base_03:962:22: error: no matching function for call to '__invoke' typedef decltype(__invoke(_VSTD::declval<_Fp>())) type; usr/bin/../lib/c++/v1/__config:496:32: note: expanded from macro 'decltype' #define decltype(x) __typeof__(x) usr/bin/../lib/c++/v1/__functional_base_03:1019:14: note: in instantiation of template class 'std::__1::__invoke_return<const int &, false>' requested here typename __invoke_return<type&>::type ./boost_no_cxx_hdr_functional.ipp:23:4: note: in instantiation of template class 'std::__1::reference_wrapper<const int>' requested here std::cref(i); ./boost_no_cxx_hdr_functional.ipp:36:9: error: no member named 'bind' in namespace 'std'; did you mean 'find'? std::bind(f, std::placeholders::_1, 0.0f);

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[GIT] Access
by Artyom Beilis 16 Apr '14

16 Apr '14

I hadn't committed changes for a while. >From what I've read in the mailing list there was a move to GIT and svn was closed. However I can't find information on the GIT at the boost site. Are we still using SVN? Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.com/ CppDB - C++ SQL Connectivity: http://cppcms.com/sql/cppdb/

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Re: [boost] -serialization- segfault on startup
by Biddiscombe, John A. 16 Apr '14

16 Apr '14

Andrey Thanks for the info. I purged every stray lib I could find - double checked all ld_library_path entries and discovered there was a shared lib from a previous build on my path which was almost certainly the culprit in this case. However, now the filesystem error has gone and I'm left with a very similar one which previously was bothering me from boost.serialization. This one I can't make disappear by cleaning paths because there's nothing bad left that might be a problem. I tried this time with boost_1.54 just to see if anything changed. does this stack trace look familiar to anyone? thanks JB #0 0x00000080a0b272f4 in ._dl_fixup () from /lib64/ld64.so.1 #1 0x00000080a0b2fd78 in ._dl_runtime_resolve () from /lib64/ld64.so.1 #2 0x00000fffb689869c in ._ZN5boost13serialization9singletonINS_7archive6detail22archive_serializer_mapIN3hpx4util24portable_binary_oarchiveEEEE12get_instanceEv () at /gpfs/bbp.cscs.ch/home/biddisco/apps/gcc-4.8.2/boost_1_54_0/include/boost-1_54/boost/serialization/singleton.hpp:128 #3 0x00000fffb3a93008 in ._Z41__static_initialization_and_destruction_0ii () at /gpfs/bbp.cscs.ch/home/biddisco/apps/gcc-4.8.2/boost_1_54_0/include/boost-1_54/boost/serialization/singleton.hpp:149 #4 0x00000fffb3a93064 in ._GLOBAL__sub_I_portable_binary_oarchive.cpp () at /gpfs/bbp.cscs.ch/home/biddisco/src/hpx/src/util/portable_binary_oarchive.cpp:207 #5 0x00000fffb3a969f8 in .__do_global_ctors_aux () from /gpfs/bbp.cscs.ch/home/biddisco/bgas/gcc/build/hpx/lib/hpx/libhpx_serializationd.so.0 #6 0x00000fffb3a89ae4 in ._init () from /gpfs/bbp.cscs.ch/home/biddisco/bgas/gcc/build/hpx/lib/hpx/libhpx_serializationd.so.0 #7 0x00000080a0b27bf0 in ._dl_init_internal () from /lib64/ld64.so.1 #8 0x00000080a0b154dc in ._dl_start_user () from /lib64/ld64.so.1

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filesystem segfault on startup
by Biddiscombe, John A. 16 Apr '14

16 Apr '14

I’m using a BGQ machine and have compiled boost 1_55 using gcc4.8.2, the application I am testing does not use filesystem itself, but the libraries it pulls in do. On startup I have segfaults with a stack trace like this (below) Can anyone tell what is going wrong (lots of locale related problems on this machine it seems). I have no knowledge of boost.filesystem internals and I would like to work around this if possible. Thanks JB #0 0x00000080a0b272f4 in ._dl_fixup () from /lib64/ld64.so.1 #1 0x00000080a0b2fd78 in ._dl_runtime_resolve () from /lib64/ld64.so.1 #2 0x00000fffb6ef9384 in ._ZN5boost10filesystem18directory_iteratorC1Ev () at /gpfs/bbp.cscs.ch/home/biddisco/apps/gcc-4.8.2/boost_1_55_0/include/boost/filesystem/operations.hpp:676 #3 0x00000fffb3aace44 in ._Z41__static_initialization_and_destruction_0ii () at libs/filesystem/src/operations.cpp:248 #4 0x00000fffb3aacf2c in ._GLOBAL__sub_I_operations.cpp () at libs/filesystem/src/operations.cpp:2230 #5 0x00000fffb3ab8a78 in .__do_global_ctors_aux () from /gpfs/bbp.cscs.ch/home/biddisco/apps/gcc-4.8.2/boost_1_55_0/lib/libboost_filesystem.so.1.55.0 #6 0x00000fffb3aa32e4 in ._init () from /gpfs/bbp.cscs.ch/home/biddisco/apps/gcc-4.8.2/boost_1_55_0/lib/libboost_filesystem.so.1.55.0 #7 0x00000080a0b27bf0 in ._dl_init_internal () from /lib64/ld64.so.1 #8 0x00000080a0b154dc in ._dl_start_user () from /lib64/ld64.so.1

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filesystem segfault on startup
by Biddiscombe, John A. 16 Apr '14

16 Apr '14

I'm using a BGQ machine and have compiled boost 1_55 using gcc4.8.2, the application I am testing does not use filesystem itself, but the libraries it pulls in do. On startup I have segfaults with a stack trace like this (below) Can anyone tell what is going wrong (lots of locale related problems on this machine it seems). I have no knowledge of boost.filesystem internals and I would like to work around this if possible. Thanks JB #0 0x00000080a0b272f4 in ._dl_fixup () from /lib64/ld64.so.1 #1 0x00000080a0b2fd78 in ._dl_runtime_resolve () from /lib64/ld64.so.1 #2 0x00000fffb6ef9384 in ._ZN5boost10filesystem18directory_iteratorC1Ev () at /gpfs/bbp.cscs.ch/home/biddisco/apps/gcc-4.8.2/boost_1_55_0/include/boost/filesystem/operations.hpp:676 #3 0x00000fffb3aace44 in ._Z41__static_initialization_and_destruction_0ii () at libs/filesystem/src/operations.cpp:248 #4 0x00000fffb3aacf2c in ._GLOBAL__sub_I_operations.cpp () at libs/filesystem/src/operations.cpp:2230 #5 0x00000fffb3ab8a78 in .__do_global_ctors_aux () from /gpfs/bbp.cscs.ch/home/biddisco/apps/gcc-4.8.2/boost_1_55_0/lib/libboost_filesystem.so.1.55.0 #6 0x00000fffb3aa32e4 in ._init () from /gpfs/bbp.cscs.ch/home/biddisco/apps/gcc-4.8.2/boost_1_55_0/lib/libboost_filesystem.so.1.55.0 #7 0x00000080a0b27bf0 in ._dl_init_internal () from /lib64/ld64.so.1 #8 0x00000080a0b154dc in ._dl_start_user () from /lib64/ld64.so.1 -- John Biddiscombe, email:biddisco @.at.@ cscs.ch http://www.cscs.ch/ CSCS, Swiss National Supercomputing Centre | Tel: +41 (91) 610.82.07 Via Trevano 131, 6900 Lugano, Switzerland | Fax: +41 (91) 610.82.82

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[align] Review.
by Mostafa 16 Apr '14

16 Apr '14

For easier tracking by the Review Manager I am going to break up my review into multiple parts which will be top-level responses to this post.

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[algorithm] any_of does not call std::find - bad performance
by Albert Yiamakis 15 Apr '14

15 Apr '14

Hello, Is there a particular reason why Boost.Algorithm's any_of does not call std::find? I have devised a simple benchmark that shows it to perform much worse (compiling with gcc): http://pastebin.com/nrgtTfPX boost::find is almost as fast as std::find - no surprises, as it calls it. any_of is considerably slower, whatever the optimization level. I have not dug in the implementation of std::find to determine why; perhaps the compiler recognizes this is a sorted range, perhaps it's even capable of doing the calculation at compile time. Whatever the case however, surely any_of should also call std::find to reap the same benefits? Albert

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