June 2019 - 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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out_ptr review is extended until Wednesday, July 10
by Zach Laine 26 Jun '19

26 Jun '19

We don't have enough reviews yet, so we're extending the review by two weeks. Please review this small and useful library! >From the original announcement: The formal review of JeanHeyd Meneide's out_ptr library starts Sunday, June 16th and ends on Wednesday, June 26th. out_ptr is a library for making it easy to interoperate between smart pointers and traditional C-style initialization and allocation interfaces. It also enables doing so in a way that allows library authors to opt into speed optimizations for their smart pointers that give them performance equivalent to typical C pointers (see benchmarks ( https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/benchmarks.adoc) and the Standard C++ proposal for more details). Online docs can be found here: https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc The GitHub repository is available here: https://github.com/ThePhD/out_ptr Also, there is an associated standards proposal: https://thephd.github.io/vendor/future_cxx/papers/d1132.html We encourage your participation in this review. At a minimum, please state: - Whether you believe the library should be accepted into Boost - Your name - Your knowledge of the problem domain You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s)? * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? All issues discussed during this review will be tracked on the library's GitHub issue tracker at https://github.com/ThePhD/out_ptr/issues. Zach

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out_ptr's formal review starts now!
by Zach Laine 25 Jun '19

25 Jun '19

Dear Boost community, The formal review of JeanHeyd Meneide's out_ptr library starts Sunday, June 16th and ends on Wednesday, June 26th. out_ptr is a library for making it easy to interoperate between smart pointers and traditional C-style initialization and allocation interfaces. It also enables doing so in a way that allows library authors to opt into speed optimizations for their smart pointers that give them performance equivalent to typical C pointers (see benchmarks ( https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/benchmarks.adoc) and the Standard C++ proposal for more details). Online docs can be found here: https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc The GitHub repository is available here: https://github.com/ThePhD/out_ptr Also, there is an associated standards proposal: https://thephd.github.io/vendor/future_cxx/papers/d1132.html We encourage your participation in this review. At a minimum, please state: - Whether you believe the library should be accepted into Boost - Your name - Your knowledge of the problem domain You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s)? * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? All issues discussed during this review will be tracked on the library's GitHub issue tracker at https://github.com/ThePhD/out_ptr/issues. Regards, Zach Laine

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[boost-users][asio] Make asio::strand using tcp::socket
by Fiver Dev 24 Jun '19

24 Jun '19

Hello everyone, How do I create this strand using the io_context of the socket in boost 1.70. asio::ip::tcp::socket socket; asio::io_context::strand strand( socket.get_executor().context() ); Thanks Tom

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[boost-users] [compiler] Boost VC++ 14.2 test compiler
by Alex J 23 Jun '19

23 Jun '19

Hi, Does anybody know when boost will add VC++ 14.2 as a 'primary compiler tested' ?. At the moment they only have 14.1. Thanks

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B2 release 4.0.0
by Rene Rivera 23 Jun '19

23 Jun '19

After even more years of development the landscape of build systems has changed considerably, and so has the landscape of compilers. This version marks the start of B2 transitioning to a C++ implementation. Initially this means that the engine will be compiled as C++ source but that source is still the base C implementation. Over time it will transform to a C++ code base in both the engine and build system. Some changes in this start: - Requires C++ 11 to build engine. - Simplified build scripts to make it easier to maintain. - Building with C++ optimizations gives an immediate performance improvement. *Other changes in this release:* - Add support for using prebuilt OpenSSL. -- *Damian Jarek* - Define the riscv architecture feature. -- *Andreas Schwab* - Add ARM64 as a valid architecture for MSVC. -- *Marc Sweetgall* - Set coverage flags, from coverage feature, for gcc and clang. -- *Damian Jarek* - Add s390x CPU and support in gcc/clang. -- *Neale Ferguson* - Support importing pkg-config packages. -- *Dmitry Arkhipov* - Support for leak sanitizer. -- *Damian Jarek* - Fix missing /manifest option in clang-win to fix admin elevation for exes - with "update" in the name. -- *Peter Dimov* - Add freertos to os feature. -- *tee3* - Default parallel jobs (-jX) to the available CPU threads. -- *Rene Rivera* - Simpler coverage feature. -- *Hans Dembinski* - Better stacks for sanitizers. -- *James E. King III* *WARNING*: The default number of parallel jobs has changed in this release from "1" to the number of cores. There are circumstances when that default can be larger than the allocated cpu resources, for instance in some virtualized container installs. *Continuously tested on:* - Linux Clang 3.5, 3.6, 3.7, 3.8, 3.9, 4, 5, 6, 7, 8 - Linux GCC 4.7, 4.8, 4.9, 5, 6, 7, 8, 9 - macOS Xcode 8.3.3, 9.0, 9.0.1, 9.1, 9.2, 9.3, 9.3.1, 9.4, 9.4.1, 10.0, 10.1, 10.2, 10.2.1 - Windows MinGW 8.1.0 - Windows VS 2013, 2015, 2017, 2019 Documentation and more at <https://boostorg.github.io/build/> -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

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[boost] Does boost 1.70 officially support VS2019 14.2 compiler
by Alex J 20 Jun '19

20 Jun '19

Hi, Does boost 1.70 officially support VS2019 14.2 compiler ? Boost.org doesn't explicitly say that they does or doesn't support VS2019 14.2. Also they have 14.1 listed as a "primary compiler tested". Thanks Alex

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[release] 1.71.0 deadline for new libraries approaching
by Michael Caisse 19 Jun '19

19 Jun '19

One week from today master will closed for new libraries and breaking changes. Thanks, -- The Boost Release Team Boost Calendar with the release schedule: <http://www.boost.org/development/index.html>

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How to set up user-config.jam properly?
by Robert Dailey 19 Jun '19

19 Jun '19

I am working on a user-config.jam file to build boost 1.70 against Android NDK r19. My jam file looks like this: ``` import os ; local ndk_cxx = [ os.environ CXX ] ; local ndk_ar = [ os.environ AR ] ; local ndk_ranlib = [ os.environ RANLIB ] ; local ndk_flags = [ os.environ CXXFLAGS ] ; using clang : x86 : "$(ndk_cxx)" : <cxxflags>"$(ndk_flags)" <archiver>"$(ndk_ar)" <ranlib>"$(ndk_ranlib)" <architecture>x86 <address-model>32 <binary-format>x86 <abi>x86 ; using clang : armeabi-v7a : "$(ndk_cxx)" : <cxxflags>"$(ndk_flags)" <archiver>"$(ndk_ar)" <ranlib>"$(ndk_ranlib)" <architecture>arm <address-model>32 <binary-format>elf <abi>aapcs ; ``` And my command line is: ``` ./bootstrap.sh --prefix=$INSTALL_DIR/boost || cat bootstrap.log ./b2 -j8 \ --without-python \ --without-test \ target-os=android \ toolset=clang-${ANDROID_ABI} \ variant=release \ threading=multi \ threadapi=pthread \ link=static \ runtime-link=shared \ install ``` When I run the commands above I get: ``` /_build/boost_1_70_0/tools/build/src/build/feature.jam:314: in implied-subfeature from module feature error: "armeabi" is not a known subfeature value of <toolset>clang /_build/boost_1_70_0/tools/build/src/build/feature.jam:497: in feature.validate-value-string from module feature /_build/boost_1_70_0/tools/build/src/build/property.jam:341: in validate1 from module property /_build/boost_1_70_0/tools/build/src/build/property.jam:367: in validate from module property /_build/boost_1_70_0/tools/build/src/build/property.jam:376: in property.validate-property-sets from module property /_build/boost_1_70_0/tools/build/src/build/toolset.jam:187: in toolset.flags from module toolset /_build/boost_1_70_0/tools/build/src/tools/common.jam:447: in common.handle-options from module common /_build/boost_1_70_0/tools/build/src/tools/clang-linux.jam:62: in clang-linux.init from module clang-linux /_build/boost_1_70_0/tools/build/src/build/toolset.jam:44: in toolset.using from module toolset /_build/boost_1_70_0/tools/build/src/tools/clang.jam:33: in clang.init from module clang /_build/boost_1_70_0/tools/build/src/build/toolset.jam:44: in toolset.using from module toolset /_build/boost_1_70_0/tools/build/src/build/project.jam:1104: in using from module project-rules /home/build/user-config.jam:28: in modules.load from module user-config /_build/boost_1_70_0/tools/build/src/build-system.jam:255: in load-config from module build-system /_build/boost_1_70_0/tools/build/src/build-system.jam:453: in load-configuration-files from module build-system /_build/boost_1_70_0/tools/build/src/build-system.jam:607: in load from module build-system /_build/boost_1_70_0/tools/build/src/kernel/modules.jam:295: in import from module modules /_build/boost_1_70_0/tools/build/src/kernel/bootstrap.jam:139: in boost-build from module /_build/boost_1_70_0/boost-build.jam:17: in module scope from module ``` The value of `ANDROID_ABI` is either `x86` or `armeabi-v7a`. What I'm not sure about is this syntax in the JAM file: ``` using <platform> : <subfeature> : <toolchain> ``` Why is this failing? Can someone explain this strange syntax in the JAM file? What is "subfeature" for and what values does it accept? How does this map to the command line arguments? How should I best set up my user config jam file for providing different build parameters per architecture in a cross-compilation setting (building for Android)?

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Re: [Boost-users] [CMake] Specifying name of library file on CMake command line?
by Osman Zakir 17 Jun '19

17 Jun '19

From: Kyle Edwards <kyle.edwards(a)kitware.com> Sent: Monday, June 17, 2019 6:49 PM To: Osman Zakir; cmake(a)cmake.org Subject: Re: [CMake] Specifying name of library file on CMake command line? On Mon, 2019-06-17 at 13:47 +0000, Osman Zakir wrote: >> I want to know how to specify the name of a library I file I want to >> link against. How do I do this? I wanted to build a library with a >> static runtime and static libs; it requires linking against a Boost >> library which I did build with static runtime but when I tried to >> build it, I had linker errors because the dynamic version of the >> library was used instead of the static one. I want to somehow make >> it use the static one. So yeah, how do I do this? Is there a way? >Are you using the FindBoost module? >https://cmake.org/cmake/help/v3.14/module/FindBoost.html >Kyle Yes, I'm using that module. I didn't make any changes to it; it came with the third-party library I'm trying to build.

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Boost.Units: unit type for dBm
by Carel Combrink 17 Jun '19

17 Jun '19

Hi, I have a system that uses dBm to indicate Signal Amplitude, how do I create a type using Boost.Units for this? At the moment I am not concerned about any type of conversions between power and this ratio. Any help will be appreciated. I am already using boost.unit successfully for other units and conversions with the help from the mailing list. I want to now define the correct strong type for this type for consistency. Regards, Carel

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Building Boost.Python for a custom Python installation
by Evan Driscoll 14 Jun '19

14 Jun '19

I have a build of Python I made that was installed (--prefix) at ~/python-3.5.2-asan/. I want to build Boost.Python against it. I have Boost 1.70.0. I have tried a variety of permutations of passing various --with-python options and such to both bootstrap and b2 with no success. Perhaps the closest I've gotten is ./bootstrap.sh --prefix=$HOME/boost-1.70.0/ --with-python=$HOME/python-3.5.2-asan/bin/python3.5 python-debugging=on ./b2 --with-python python-debugging=on -d+2 -j8 cxxflags=-fsanitize=address cflags=-fsanitize=address but with those commands compilation fails because it is looking for include files in ...../include/python3.5/ instead of ..../include/python3.5dm While I'm at it, I had to add cflags and cxxflags explicitly instead of doing what some documentation [1] said to, because: ./b2 --with-python python-debugging=on -d+2 -j8 address-sanitizer=1 /home/evan/Downloads/boost_1_70_0/tools/build/src/build/feature.jam:327: in validate-feature from module feature error: unknown feature "<address-sanitizer>" [1] https://boostorg.github.io/build/manual/develop/index.html#_sanitizers Evan

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[Process] Zombie Processes left behind
by Ryan Ruhge 05 Jun '19

05 Jun '19

Boost Team: We are trying to use boost process to have an always running process spawn child processes in a fire and forget manner (don't wait or block on the process that was just spawned). The issue we are running into is that the child processes become zombie processes when finished until the parent process completes. However in our system the parent process is never intended to complete, it is always running and listening. We have provided code snippets which give a simple example of the symptom we are experiencing. It's an infinite loop (imitating our always running process) that spawns processes that run and then become zombies instead of finishing (I included a sleep so it doesn't spawn processes too quickly). Please advise on whether there is something else we can do, if we are using child or spawn wrong, or if we are using boost process in a manner that it is not intended to be used. Thanks, Ryan Ruhge #include <boost/process.hpp> using namespace std; int main() { while (true) { boost::process::spawn("sleep 10"); sleep(5); } } #include <boost/process.hpp> using namespace std; int main() { while (true) { boost::process::child childProcess("sleep 10"); childProcess.detach(); sleep(5); } }

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