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boost.python compilation error (newbie)
by maths soso 11 Jul '21

11 Jul '21

I'm new to boost, I decided installing it by following instructions provided at SO: https://stackoverflow.com/a/24086375/10213771 (The only difference is that I used version 1.76) Everything went fine, then I decided to compile this C++ file: char const* greet(){ return "hello, world";} #include <boost/python.hpp> BOOST_PYTHON_MODULE(hello_ext){ using namespace boost::python; def("greet", greet);} Since boost.python is not header only library, I needed to link to it on compilation, I used the following compile command: g++ -I ~/Desktop/boost_1_76_0/ -I /usr/include/python2.7/ main.cpp -o prog ~/Desktop/boost_1_76_0/stage/lib/libboost_python27.a but I get the following errors: /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start': (.text+0x24): undefined reference to `main' /usr/bin/ld: /home/sofiane/Desktop/boost_1_76_0/stage/lib/libboost_python27.a(registry.o): in function `boost::python::converter::registration::get_class_object() const': ... /usr/bin/ld: function_doc_signature.cpp:(.text+0x1de): undefined reference to `PyObject_IsTrue' /usr/bin/ld: function_doc_signature.cpp:(.text+0x23e): undefined reference to `PyInt_FromLong' /usr/bin/ld: function_doc_signature.cpp:(.text+0x28b): undefined reference to `PyInt_FromLong' ...

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[release] Boost 1.77.0 Beta 1 Release Candidate 1 is available
by Marshall Clow 10 Jul '21

10 Jul '21

The first release candidates for the 1.77.0 beta release are now available at: https://boostorg.jfrog.io/artifactory/main/beta/1.77.0.beta1/source/ 1aba2bf9416d71026c9e6bbd10a2b7cfb31b0950baa7ad0861dfb74984d96bd9 boost_1_77_0_b1_rc1.zip 55126d149664541ffc9fd1f41b2ec67146d69bdab92e41da4bb8610b755ca9ec boost_1_77_0_b1_rc1.7z 1aabe7704e91f4f8d97b81d03ddc21c3396f4b72fc4041f01bfcfc128bac0d73 boost_1_77_0_b1_rc1.tar.gz 3d5801790c96d2bc9ed23372c4f9fd963bc2f39fe540e35d7b4fe586ba77dfa7 boost_1_77_0_b1_rc1.tar.bz2 The web site has NOT YET been updated. 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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The Master branch will be closing for the 1.77.0 beta release TODAY!
by Marshall Clow 07 Jul '21

07 Jul '21

If you have changes for the beta, they need to be merged to master today. See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release managers

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The deadline for Major changes for Boost 1.77.0 is TODAY!
by Marshall Clow 04 Jul '21

04 Jul '21

See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release Managers

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Poor performance on windows with logging sinks::file_collector when two file logs use same directory. Thoughts?
by Nicholas Neumann 24 Jun '21

24 Jun '21

I've got two different rotating file logs that point to the same directory (with different file name patterns). Is this in general just a bad idea? They end up sharing the same file_collector, which seems wrong, so perhaps that is a clue that I shouldn't have my logs set up like this. In production I've got a service that compresses, archives, and manages the size of the logs. But in dev, I don't, so the number of files in the directory slowly grew. But the startup time for my program grew much faster. On windows the scan_for_files function in the collector has a loop that is O(mn), where m is the number of files in the directory, and n is the number that matched in previous calls to the scan_for_files function This means the scan_for_files for the first rotating file log in the directory has no issue (n is 0), but the second can be problematic. It iterates over the files in the directory and for each file in the directory, it calls filesystem::equivalent on all of the matches from previous scan_for_files calls. On windows, filesystem::equivalent is particularly heavy, opening handles to both files. Thoughts? Is the two file logs getting the same collector the real issue? Or is it my pointing two file logs to the same directory? I see some ways to mitigate the slowdown in scan_for_files - e.g., filesystem::equivalent could be called after all of the method/match_pattern check, but the two file logs sharing the same collector feels like the real issue.

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The deadline for new libraries and breaking changes in Boost 1.77.0 is this Wednesday, June 23
by Marshall Clow 21 Jun '21

21 Jun '21

See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release Managers

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Re: [boost] What has become of John Maddock's implementation of the Remez algorithm for Chebychev approximation?
by Bjorn Reese 18 Jun '21

18 Jun '21

On 6/15/21 11:48 PM, Joachim Wuttke via Boost wrote: > Until v1.53, Boost Math had doc pages [1,2] on the Remez algorithm. > This algorithm [3] computes the coefficents of the Chebyshev polynomial > that approximates a given function. Page [2] refers to actual code In addition to John's reply, I wanted to add that Boost.Math has direct support for Chebyshev polynomials now: https://www.boost.org/doc/libs/release/libs/math/doc/html/math_toolkit/sf_p…

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What has become of John Maddock's implementation of the Remez algorithm for Chebychev approximation?
by Joachim Wuttke 16 Jun '21

16 Jun '21

Until v1.53, Boost Math had doc pages [1,2] on the Remez algorithm. This algorithm [3] computes the coefficents of the Chebyshev polynomial that approximates a given function. Page [2] refers to actual code in directory libs/math/minimax. This code can still be found on GitHub [4], but maintenance status and dependences are unclear. Anybody around who knows anything about this code? Kind regards, Joachim [1] https://www.boost.org/doc/libs/1_53_0/libs/math/doc/sf_and_dist/html/math_t… [2] https://www.boost.org/doc/libs/1_53_0/libs/math/doc/sf_and_dist/html/math_t… [3] https://en.wikipedia.org/wiki/Remez_algorithm [4] https://github.com/boostorg/math/tree/develop/tools/minimax -- Dr. Joachim Wuttke group leader Scientific Computing Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science at MLZ https://computing.mlz-garching.de https://jugit.fz-juelich.de/mlz

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Using Boost.Test header-only from CMake
by Peter Dimov 15 Jun '21

15 Jun '21

Some libraries (I encountered this when porting the tests of Signals2) use Boost.Test in header-only mode, by including <boost/test/included/unit_test.hpp> without linking to anything. This worked in the "legacy" structure where all headers are always available, but doesn't work under CMake where you have to link to header-only libraries in order to get the proper include path. Should we make an attempt to support this use by declaring a special header-only target in Boost.Test (e.g. Boost::included_unit_test), or is that a waste of time? One can as well link to the proper Boost::unit_test_framework (and then even use it header-only, although there's not much point in doing so.) I'm inclined towards "waste of time".

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Re: [boost] boost-json apt-get packge
by Vollaro, John 14 Jun '21

14 Jun '21

Date: Fri, 11 Jun 2021 01:42:18 +0300 From: "Peter Dimov" <pdimov(a)gmail.com> To: <boost(a)lists.boost.org> Subject: Re: [boost] boost-json apt-get packge Message-ID: <05f001d75e49$decba2f0$9c62e8d0$(a)gmail.com> Content-Type: text/plain; charset="utf-8" Vollaro, John wrote: > Is their a apt package that includes boost-json? For what distro? debian > This apt packages did not include boost-json > > apt-get install libboost1.76-all-dev Should be libboost1.76-json-dev. Could not find this package. This e-mail, including attachments, may include confidential and/or proprietary information, and may be used only by the person or entity to which it is addressed. If the reader of this e-mail is not the intended recipient or his or her authorized agent, the reader is hereby notified that any dissemination, distribution or copying of this e-mail is prohibited. If you have received this e-mail in error, please notify the sender by replying to this message and delete this e-mail immediately.

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