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Building Boost With clang-cl.exe?
by Osman Zakir 12 Aug '20

12 Aug '20

I tried to build Boost version 1.73.0 with clang-cl.exe but ran into trouble. I've attached my project-config.jam file to this message for you guys to review, as well as the config.log file which shows the output for the run. The command I ran on the command line when invoking b2 was "b2 --build-type=complete address-model=64 install" But I saw in the output that the address model and architecture wasn't set and it seemed to think I was building for Linux. What went wrong?

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[release] Boost 1.74.0 Release Candidate 2
by Marshall Clow 12 Aug '20

12 Aug '20

The second release candidates for the 1.74.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.74.0/source/> The SHA256 checksums are as follows: 903fd40074de8dc733d2f0b6b0642e43b714653eaeb79289b12161b9567fae97 boost_1_74_0_rc2.7z 83bfc1507731a0906e387fc28b7ef5417d591429e51e788417fe9ff025e116b1 boost_1_74_0_rc2.tar.bz2 afff36d392885120bcac079148c177d1f6f7730ec3d47233aa51b0afa4db94a5 boost_1_74_0_rc2.tar.gz a0e7ce67c52d816708fdeccdd8c9725626ba61254c13c18770498cacd514710a boost_1_74_0_rc2.zip Changes from RC1: * Fix a recently introduced bug in Boost.Asio where it would read from uninitialized memory. As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

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[release] Boost 1.74.0 Release Candidate 1
by Marshall Clow 11 Aug '20

11 Aug '20

The first release candidates for the 1.74.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.74.0/source/> The SHA256 checksums are as follows: 9ea3fc8573413f4d4b2c4d448110b6cb0467df834304112e143c7edb09ae71e9 boost_1_74_0_rc1.7z 8b6c429a41f7cac1880594adf8d1d6f0cc1cf19f8980c6b86ac38ef8b3d8a4e0 boost_1_74_0_rc1.tar.bz2 a0a96a9bb3863863e034cafc825b2ddba4249c7d278b76df1277295e7c7afbf2 boost_1_74_0_rc1.tar.gz d4f31cce9d5fbd55691dc2f5fb73380e95aa66426c891ceb3ebdfc6616022842 boost_1_74_0_rc1.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

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Boost-1.71.0 upgrade issue
by Tej Kumar 28 Jul '20

28 Jul '20

Hi Team, Hope you guys are doing well. I am trying to upgrade Boost to 1.71.0 version. My code is compiling and building successfully but during test run i see below error. Error seems to be related with boost chrono, even though i have included boost_chrono lib in my makefile. *undefined symbol: _ZN5boost6chrono12steady_clock3nowEv* It will be a great help if you guys can suggest something here. Thanks & Regards, Tej

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[Graph] Unable to get the edge_color in depth_first_search
by Ashish Kumar 27 Jul '20

27 Jul '20

Hello, First of all, I am new to Boost Graph Library. So, there might be a simpler or easier fix to the problem I am facing. I am trying to get the edge color after executing the boost::depth_first_search algorithm on the graph. For that, I created an edge color map and passed it to the function. Also, to log the colors of the edges, I made a visitor class, passed the color of the edge to it, and printed it to the standard output stream, for the tree_edge, back_edge, etc. But, for every edge, the value of color comes out to be 0. So, I am not able to get the color of every edge. A small snippet of how I am calling the depth_first_search function: depth_first_search(graph, visitor(dfs_visitor(root, visited_order, colors, graph)) .edge_color_map(&colors) .root_vertex(root)); The complete code along with the visitor class can be found here: https://gist.github.com/krashish8/5f8d8e613e189857bd2b0fd46dd02b29 Please suggest any possible solution to this problem. Thank you, Ashish Kumar.

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[boost] Clang on Windows - No Autolink?
by Klaim - Joël Lamotte 27 Jul '20

27 Jul '20

Hi, am I correct that autolinking is not supported by Boost when using Clang on Windows? To be clear, I'm talking about both clang++ and clang-cl drivers. The behavior I observe suggests that I am correct but looking at the autolink.hpp header I didn't understand how it decides if it should work or not. A. Joël Lamotte

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Two Graphs Common Spanning Trees Issue [GSoC]
by Prakash Tiwari 24 Jul '20

24 Jul '20

Hello, Community Members and developers, I'm student of Google Summer Of Code and contributing to the pgRouting <https://github.com/pgRouting/pgrouting/>[1]. I need to use boost algorithm boost::two_graphs_common_spanning_trees. I have gone through the documentation and try to use it (with help of example.cpp) But I found that this algorithm is not returning the expected results. I have mentioned the example that I have used and explained the expected and given results <https://github.com/prakashupes/ProposalCodes/issues/1>.[2] So, please try to figure out that is it a bug implemented algorithm or It might be possible that I'm using the algorithm in the wrong way. Thanks Prakash Tiwari [1].https://github.com/pgRouting/pgrouting/ [2]. https://github.com/prakashupes/ProposalCodes/issues/1

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jpeg resize - file size increases
by Lloyd 24 Jul '20

24 Jul '20

Hi, We tried boost gil resize example to experiment with scaling down a jpeg image file. For some images, this causes the size of the file to increase. We are using bilinear_sampler algorithm. Our aim to reduce the input image size so as to save storage/network bandwidth. Quality can be compromised to a certain extent. Which algorithm/method should we use? The code fragment is given below:- boost::gil::rgb8_image_t img; boost::gil::read_and_convert_image(InStream, img, T()); float width = (float)(img.width() * Ratio) / 100; float height = (float)(img.height() * Ratio) / 100; boost::gil::rgb8_image_t resizedImg(width, height); boost::gil::resize_view(const_view(img), view(resizedImg), boost::gil::bilinear_sampler()); boost::gil::write_view(OutStream, boost::gil::const_view(resizedImg), T()); Thanks, Lloyd

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bjam resources
by Antonis Polykratis 18 Jul '20

18 Jul '20

Hello, are there any bjam tutorials documentation about how I could create a project using bjam? Thanks

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Boost ABI/Linkage of clang vs g++
by DV Henkel-Wallace 17 Jul '20

17 Jul '20

boost-users(a)lists.boost.org We build with clang++-10 w/libc++.a and g++-10 w/libstdc++.a, so build a copy of boost in each configuration as well. This works great on the Mac development machines but the clang case doesn't generate the correct linkage on the Linux deployment machines. The correct clang linkage is std::__1::basic_string... but boost builds with std::__cxx11::basic_string Here's the linkage of libc++: $ objdump -T /usr/lib/llvm-10/lib/libc++.so.1|c++filt|grep ::basic_string|head -1 0000000000057450 g DF .text 0000000000000048 Base std::__1::locale::locale(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&) Notice: std::__1::basic_string< ... When compiling my own code with clang++-10 the correct symbol is generated: $ nm options.cc.o |c++filt |fgrep __ |fgrep ::set_option_name |head -1 0000000000000000 W fmt::v6::basic_format_context<std::__1::back_insert_iterator<fmt::v6::internal::buffer<char> >, char>::iterator... Notice std::__1:: ... However the boost object have the wrong symbol name: $ nm 3P/llvm/lib/libboost_program_options.a |c++filt |fgrep __ |fgrep ::basic_string |head -1 0000000000000000 W boost::program_options::unknown_option::unknown_option(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) Notice std::__cxx11::basic_string< ... I'm compiling boost this way: export CC=clang CXX="clang++ -stdlib=libc++" CXXSTD=c++20 ; ./b2 stdlib=libc++ toolset=clang boost.locale.icu=off boost.locale.std=off --with-atomic --with-chrono --with-date_time --with-headers --with-locale --with-log --with-program_options --with-random --with-regex --with-system --with-thread threading=multi -sNO_COMPRESSION=1 link=static install It's 1.73.0

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