March 2018 - Boost-users - lists.preview.boost.org

[interprocess] Determine size of managed_shared_memory
by Kai Benndorf 12 Oct '19

12 Oct '19

Hi all, I want to create a managed_shared_memory in exactly the size I needed. Therefore I do something like this: size = sizeof( common_managed_shared_memory ); size += sizeof( MyClassInSharedMem ); managed_shared_memory segment(create_only, "name", size ); MyClassInSharedMem allocates itself some memory by segment->allocate(). I added this also to the size, but get a boost::interprocess::bad_alloc exception on allocating this additional memory. Are there some magic bytes I forgot to add? Many thanks in advance Kai

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boost::filtered_graph filtering on vertex color... if I only had a colormap
by Brian Davis 19 Jul '19

19 Jul '19

Lets say I have a graph g (of type graph_t) and a color map (boy I wish I had a colormap): typedef boost::property_map<graph_t, boost::vertex_color_t>::type color_map_t; or is it? auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::default_color_type>(indexmap); or maybe? auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::vertex_color_t>(indexmap); or possibly some goop found on the internet? boost::make_iterator_property_map(color_map.begin(), boost::get(boost::vertex_index, data_->g), color_map[0]) or other internet goop? typedef boost::property_map<GraphType, boost::vertex_color_t>::type color_map_t; color_map_t colorMap; boost::color_map(colorMap)) or other internet goop?? std::vector<int> colorMap(num_vertices(g), boost::white_color); so confused... (certainly not surprised why bgl is not a part of stl) Can someone help explain the various types and ways of specifying colormaps and the logic for each way and means? and a function (if I could get that far without VS syntax highlighter going bonkers and gobs of compiler errors.. you know the type): make_pretty(g, colormap ) which colors the graph colormap and a filter struct for boost::filtered_graph<Graph, EdgePredicate, VertexPredicate> (where I wonder why if I only want to filter vertices I have to set boost::keep_all for EdgePredicate... sigh... I know the answer... and also know how long it found me to find/figure out boost::keep_all - and if you are looking for boost::keep_all and found it here... your welcome ;-) ) and modifying (probably incorrectly) boost::filtered_graph example to: template <typename ColorMap> struct vertex_color_filter_eq { vertex_color_filter_eq() { } vertex_color_filter_eq(ColorMap colormap/*, boost::default_color_type c*/) : m_colormap(colormap)/*, m_c(c)*/ { } template <typename Vertex> bool operator()(const Vertex& v) const { return 0 < get(m_colormap, v); //return c < get(m_colormap, v); } ColorMap m_colormap; //boost::default_color_type m_c; }; auto indexmap = boost::get(boost::vertex_index, g); auto colors = boost::make_vector_property_map<boost::default_color_type>(indexmap); // some where here I would call make_pretty(g, colors) typedef property_map<graph_t, boost::vertex_color_t>::type ColorMap_t; vertex_color_filter<ColorMap_t> filter(colors); // boost::filtered_graph<graph_t, boost::keep_all, VertexPredicate> boost::filtered_graph<graph_t, boost::keep_all, vertex_color_filter> fg(g, filter); // Later say if I could get it compile and better if it compiled and worked I could move on and auto color = boost::red_color; typedef property_map<graph_t, boost::vertex_color_t>::type ColorMap_t; vertex_color_filter<ColorMap_t> filter(colors, color); boost::filtered_graph<graph_t, boost::keep_all, vertex_color_filter> fg(g, filter); Maybe if I color them yellow, I can then reach the wizard pull back the curtain and ask how to create a color map... If I only had a color map.

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[Test] Test executable crashes always
by Nate Widmyer 26 Jun '18

26 Jun '18

Hello, I've made some unit tests with boost test before without issue, but on my latest rather ordinary test, I've been able to get Boost test to crash the executable in debug and release mode when boost test is making a report before terminating. test_exe.exe!boost::unit_test::framework::get(unsigned long id, boost::unit_test::test_unit_type t) Line 1388 C++ test_exe.exe!boost::unit_test::framework::get<boost::unit_test::test_unit>(unsigned long id) Line 208 C++ test_exe.exe!boost::unit_test::results_reporter::make_report(boost::unit_test::report_level l, unsigned long id) Line 175 C++ test_exe.exe!boost::unit_test::unit_test_main(boost::unit_test::test_suite *(*)(int, char * *) init_func, int argc, char * * argv) Line 235 C++ test_exe.exe!main(int argc, char * * argv) Line 287 C++ That's the default report_level of 'confirm' If I use report_level=short or detailed, I get a similar crash: test_exe.exe!boost::unit_test::framework::get(unsigned long id, boost::unit_test::test_unit_type t) Line 1388 C++ test_exe.exe!boost::unit_test::framework::get<boost::unit_test::test_suite>(unsigned long id) Line 207 C++ test_exe.exe!boost::unit_test::traverse_test_tree(unsigned long id, boost::unit_test::test_tree_visitor & V, bool ignore_status) Line 365 C++ test_exe.exe!boost::unit_test::results_reporter::make_report(boost::unit_test::report_level l, unsigned long id) Line 185 C++ test_exe.exe!boost::unit_test::unit_test_main(boost::unit_test::test_suite *(*)(int, char * *) init_func, int argc, char * * argv) Line 235 C++ test_exe.exe!main(int argc, char * * argv) Line 287 C++ Here's the get() method: test_unit& get( test_unit_id id, test_unit_type t ) { test_unit* res = impl::s_frk_state().m_test_units[id]; BOOST_TEST_I_ASSRT( (res->p_type & t) != 0, internal_error( "Invalid test unit type" ) ); return *res; } Crash occurs on line 2 of the function. I logged 'res' each time the function is called and many times its valid, but when it runs this one test (by itself or with others), 'res' always ends up being NULL. id seems to always be '1', and t is TUT_ANY (17) if generating a confirmation report or TUT_SUITE (16) if generating a short or detailed report. If I use the option '--report_level=no', then execution does complete fine. I followed through on some process of elimination and it seems to be related to using a fixture? Having no test body still causes the crash. It wasn't until I removed the fixture (and its usage in the body of the test) did the executable not crash. I ensured that I was using the standard fixture model found here: http://www.boost.org/doc/libs/1_64_0/libs/test/doc/html/boost_test/tests_or… OS is Win 7 w/ VS2015 boost is 1.64.0 and was built with: b2 toolset=msvc-14.0 link=static runtime-link=static variant=debug address-model=64 --without-atomic --without-container --without-context --without-coroutine --without-coroutine2 --without-graph --without-graph_parallel --without-iostreams --without-locale --without-math --without-mpi --without-serialization --without-signals --without-type_erasure --without-wave -j4 --abbreviate-paths --without-python -d2 Any help would of something to look at or change would be appreciated. Thanks for your time, Nathan

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[release] Boost 1.67.0 Beta 1
by Daniel James 07 Apr '18

07 Apr '18

Boost release 1.67.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.67.0.beta.1/source/> The SHA256 checksums are as follows: 154cf490da858fd9c2307bb904b07a42cbe8355ecf99d5477f0d843c6d03cdda boost_1_67_0_b1.7z 0d854b208fefaeb5837d6c417f505b189275e32d017f6226001fb165a5ac51ed boost_1_67_0_b1.tar.bz2 6eb3f9ca8db355765f41361e1e26976228f0c2dff400aade8a5e97aec6aa59f4 boost_1_67_0_b1.tar.gz 678a6459f2517932536ec97297be1de46ea073f2e2ee17ec8397b80aa0953f49 boost_1_67_0_b1.zip For details of what's in the release, see <http://www.boost.org/users/history/version_1_67_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

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Pointer Container Library changes in 1.66.0
by Kevin Hardman 06 Apr '18

06 Apr '18

I am seeing changes in the Pointer Container Library that are preventing my existing application from compile. I see no notice of changes in the 1.66.0 release notes <http://www.boost.org/users/history/version_1_66_0.html <http://www.boost.org/users/history/version_1_66_0.html>>. Is there documentation on the changes and what is required to migrate existing users to the new library? —kevin

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[ptr_map] Warning about returning address of local variable
by Bill Buklis 05 Apr '18

05 Apr '18

I'm not sure if this a potential bug/problem or just a benign warning, but when using the map_values range adaptor with a ptr_map container I get a warning about returning an address of a local variable. It seems benign as the expected processing happens, but this type of warning generally doesn't sound like a good thing. The following useless code will trigger it. #include <boost/ptr_container/ptr_map.hpp> #include <boost/range/algorithm.hpp> #include <boost/range/adaptors.hpp> struct sample { int value; }; typedef boost::ptr_map<int, sample> themap; int main() { themap data; int key = 5; data.insert(key, new sample); boost::for_each(data | boost::adaptors::map_values, [](sample* s) { s->value = 10; }); return 0; } I'm using Visual Studio 2017. I also have conformance mode (/permissive-) turned on for stricter language compliance in case it makes a difference. As an aside, I was a little surprised when trying out this little sample that the inclusion of the above headers is enough to require linking with the boost regex library. I figure it's probably a reference in the adaptors somewhere. It's not a big deal. These lib files are normally available anyway. -- Bill

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Crossbuilding for ARM
by Mats Webjörn/WIKAB 30 Mar '18

30 Mar '18

I'm trying to build for ARM, and have some problems in making b2 find user-config.jam when it's located outside boost root dir. First I go to boost/tools/build and run ./b2 install -prefix=/home/administrator/project/myproj/build/boost Then I run ./b2 toolset=gcc-arm --build-dir=/home/administrator/project/myproj/build/boost stage According to http://www.boost.org/build/doc/html/bbv2/overview/configuration.html Boost.Build<http://www.boost.org/build/doc/html/bbv2/overview/configuration.html%20Boos…> will search $HOME and $BOOST_BUILD_PATH, but if I add --debug-configuration to b2 command then I can see that it searches '/home/administrator' = $HOME '/home/administrator/project/myproj/externals/boost/tools/build/src/kernel' '/usr/share/boost-build' '/home/administrator/project/myproj/externals/boost/tools/build/src/kernel' '/home/administrator/project/myproj/externals/boost/tools/build/src/util' '/home/administrator/project/myproj/externals/boost/tools/build/src/build' '/home/administrator/project/myproj/externals/boost/tools/build/src/tools' '/home/administrator/project/myproj/externals/boost/tools/build/src/contrib' '/home/administrator/project/myproj/externals/boost/tools/build/src/.'. Where none of the directories searched is the one I've provided as buid directory. It seems odd that $BOOST_BUILD_PATH should be "the one in the top-level directory of your Boost.Build installation" since http://www.boost.org/build/doc/html/bbv2/overview/invocation.html describes --build-dir as "the build directories for all project roots being built". It seems like the documentation isn't correct. I'm just not sure which one is right and which is wrong. Has anyone crossbuilt for ARM on Linux? Regards Mats Webjörn E-Mail: konsult(a)webjorn.com Webjörn IngenjörsKonsult AB Tel +46 8 584 238 80 Solhemsbackarna 75A Fax +46 8 445 69 21 SE-163 56 SPÅNGA Mobil +46 70 639 16 99 Sweden

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[Boost::Test] short form of catch_system_errors not working
by Konstantin Kivi 30 Mar '18

30 Mar '18

Occasionally I need a core dump if testing goes wrong. Boost test have the following option ------------ Parameter: catch_system_errors Allows to switch between catching and ignoring system errors (signals). Command line formats: --[no_]catch_system_errors[=<boolean value>] -s[ <boolean value>] ------------------- I never managed to get short options to work and has to search for a long option exact name. Neither '-s no', '-s false' , -sno with or without quotes are not accepted. examples ----- $ test_app -s no Boost.Test WARNING: token "no" does not correspond to the Boost.Test argument and should be placed after all Boost.Test arguments and the -- separator. For example: test_app --random -- no ------ $ test_app "-s no" Invalid separator for the parameter catch_system_errors in the argument -s no ----- Is it a known bug? Best regards, Konstantin

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[boost][interprocess] Need clarification on file_lock documentation
by Rob Conde 29 Mar '18

29 Mar '18

The documentation of boost::interprocess::file_lock has some cautions on synchronization limitations: * It's unspecified if a file_lock synchronizes two threads from the same process. * It's unspecified if a process can use two file_lock objects pointing to the same file. But then gives the guidance: * For each file, use a single file_lock object per process. * Use the same thread to lock and unlock a file. I then created the following example: <https://wandbox.org/permlink/dO2rRDCHVWBE3pGr>https://wandbox.org/permlink/3CNfkA3RcMkwbd2v #include <fstream> #include <iostream> #include <cstdlib> #include <boost/interprocess/sync/file_lock.hpp> #include <boost/interprocess/sync/scoped_lock.hpp> #include <boost/filesystem.hpp> #include <mutex> #include <thread> #include <chrono> int main() { std::ofstream("f.txt"); boost::interprocess::file_lock lock("f.txt"); std::mutex mtx; const size_t max = 100; size_t t1Count = 0; std::thread t1 ( [&lock,&t1Count,&mtx,max]() { while(t1Count < max) { //std::lock_guard<std::mutex> mtxLock(mtx); boost::interprocess::scoped_lock<boost::interprocess::file_lock> guard(lock); std::cout << "Number 1" << std::endl; t1Count++; std::this_thread::sleep_for(std::chrono::milliseconds(1)); } } ); size_t t2Count = 0; std::thread t2 ( [&lock,&t2Count,&mtx,max]() { while(t2Count < max) { //std::lock_guard<std::mutex> mtxLock(mtx); boost::interprocess::scoped_lock<boost::interprocess::file_lock> guard(lock); std::cout << "Number 2" << std::endl; t2Count++; std::this_thread::sleep_for(std::chrono::milliseconds(1)); } } ); t1.join(); t2.join(); return 0; } It only works properly if the std::mutex is used in addition to the file_lock. That was originally my thought when I read "It's unspecified if a file_lock synchronizes two threads from the same process.", but it seemed like I was following the guidance "Use the same thread to lock and unlock a file.". If I haven't messed anything up, I would probably update the documentation to say something like: "If utilitizing the file_lock from multiple threads within the same process, synchronize access to the file_lock with an intraprocess synchronization mechanism such as a mutex." Otherwise, is it a bug? Thanks, Rob

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[beast] Custom, application specific header
by DePizzottri 28 Mar '18

28 Mar '18

Hi, I need to send custom application specific header in the response, but http::response operates only with set of predefined http::field values. Does anyone know how can I set custom field without implementing own `fields` class? Or is there any tips or example how can it be implemented (I know about Fields/FieldsWriter concepts)? -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Users-f2553780.html

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