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Lambda testcase fails when optimization enabled in gcc and llvm
by navya deepika garakapati 19 Jul '19

19 Jul '19

Hi Devs, consider below reduced testcase from boost lamda. $cat result_of_tests.cpp #include <boost/lambda/lambda.hpp> #include <stdio.h> template<class A, class F> typename boost::result_of<F(A)>::type apply1(F f, A b) { return f(b); } using namespace boost::lambda; int main(int, char *[]) { int one = 1; int d= (apply1<int>(_1 ,one) == 1); printf("\n%d\n",d); return 0; } when compiled with optimization O2 $g++ result_of_tests.cpp -I ./boost_1_70_0 -O2 $./a.out 0 And,when we compile same testcase with O0 $g++ result_of_tests.cpp -I ./boost_1_70_0 -O0 $./a.out 1 The above testcases is demonstrated with g++ compiler but behavior is same on clang as well. so we thought that this may be boost testcase issue. When we replace , int d= (apply1<int>(_1 ,one) == 1); with int d= (apply1<int&>(_1 ,one) == 1); testcase gives correct result with or without optimization. Wanted to confirm here,is it valid testcase or we have to modify testcase as per above? Thanks, Navya

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Review request for LEAF, review manager needed
by Emil Dotchevski 19 Jul '19

19 Jul '19

I'm requesting a formal review for LEAF, a C++11 error-handling library: https://zajo.github.io/leaf. Features: * Header-only, no dependencies. * No dynamic memory allocations. * Compatible with std::error_code, errno and any other error code type. * Can be used with or without exception handling. LEAF comes complete with its own result<T> type, but it is compatible with any other type with value-or-error variant semantics (like outcome::result<T>) as long as .error() returns a std::error_code. https://travis-ci.org/zajo/leaf https://ci.appveyor.com/project/zajo/leaf

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Re: [boost] [release] 1.71.0 closed for Beta
by Kenneth Porter 19 Jul '19

19 Jul '19

I'm seeing the following block of warnings repeated with several MSVC compiler versions. I'd suggest changing int to ptrdiff_t or size_t for the target type. f:\devel\Boost\boost_1_71_0\libs\locale\src\win32\api.hpp(149): warning C4244: 'argument': conversion from '__int64' to 'int', possible loss of data f:\devel\Boost\boost_1_71_0\libs\locale\src\win32\api.hpp(153): warning C4267: 'argument': conversion from 'size_t' to 'int', possible loss of data f:\devel\Boost\boost_1_71_0\libs\locale\src\win32\api.hpp(153): warning C4244: 'argument': conversion from '__int64' to 'int', possible loss of data f:\devel\Boost\boost_1_71_0\libs\locale\src\win32\api.hpp(170): warning C4244: 'argument': conversion from '__int64' to 'int', possible loss of data f:\devel\Boost\boost_1_71_0\libs\locale\src\win32\api.hpp(245): warning C4244: 'argument': conversion from '__int64' to 'int', possible loss of data f:\devel\Boost\boost_1_71_0\libs\locale\src\win32\api.hpp(249): warning C4244: 'argument': conversion from '__int64' to 'int', possible loss of data My build command: call .\bootstrap.bat --without-python .\b2 --without-python toolset=msvc-14.2,msvc-14.0,msvc-12.0,msvc-10.0 runtime-link=shared,static address-model=32,64

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[release] 1.71.0 closed for Beta
by Michael Caisse 19 Jul '19

19 Jul '19

The master branch is now closed for all changes except by permission for the Beta release. Also, remember to add your libraries' changes to the release notes at: <https://github.com/boostorg/website/blob/master/feed/history/boost_1_71_0.q…> Thanks, -- The Boost Release Team

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Any sample code to configure boost log for syslog?
by JH 18 Jul '19

18 Jul '19

Hi, I am using boost log to write log file in the disk of the desktop, but for an embedded system application where the NAND flash is used, to prolong the flash service life time, I try not to write log files in flash, but use journalctl to view the log in RAM. Are there any simple example to configure boost log for syslog? Thank you. - jh

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Something off my chest about Boost
by Maarten Verhage 18 Jul '19

18 Jul '19

Dear Boost people, Sorry but I need to get something off my chest regarding the Boost culture. To start of with something nice: I’m convinced Boost provides really useful facilities for C++ and some of them even make it into the standard C++ library. I do believe I can also contribute in a reasonable way. But the terse documentation keeps me from advancing. How it is currently stated on https://www.boost.org/users/faq.html “What about documentation? A very simple library might be accepted with only a well commented header file. For more substantial libraries, some form of documentation is certainly going to be expected. HTML is the preferred form.” To make Boost more accessible to people I believe Boost should ask more on this from current and new library authors. Speaking for myself. I think the first bits to get started with a library are on a sufficient level. You know the tutorial and the example code. But I get lost when I want to use the library for my own application domain. Then I do need library facilities not covered in the example code and sometimes the documentation mentions only the syntax. As I would imagine the library author working on his/her library judging whether to add a facility or not. Finally decided to add something: *the thought/motivation that goes along with that*, that would be so valuable for me to read that in the documentation!! Yes, I’m annoyed that I cannot read that in the documentation. Another issue is when example code introduces three or more facilities at once. Then it is very hard for me to see how these bits relate to each other to make it useful for myself. Ok, a few examples for what I would like to ask the Boost community to demand from the library authors: 1) In general, for the classes/functions where the user should directly deal with documentation like cppreference.com. So, with function prototypes showing the argument- and return types and a complete list of members along with what they do. 2) Specifically for Spirit X3, a part on Parser Directives: https://www.boost.org/doc/libs/develop/libs/spirit/doc/x3/html/spirit_x3/qu… I would very much like that the reason why each directive is added along with a minimal example that shows how to use just that directive. Anyway, I hope people are also interested to discus documentation policies on this mailing list. I do believe it is important. Best regards, Maarten Verhage

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ASIO socket termination crashed at boost::asio::async_read
by JH 17 Jul '19

17 Jul '19

Hi, I use boost TCP socket for months, it works well until I call a termination of smart pointer which is running at boost::asio::async_read. Could anyone explain what could be the cause for the following errors? void Comms::HandleReadBody(const boost::system::error_code &error, const uint32_t length) { ................ boost::asio::async_read(this->mHandler->Socket(), boost::asio::buffer(this->mHeader, sizeof(this->mHeader)), [=](const boost::system::error_code &status, const uint32_t length) {this->HandleReadHeader(status, length);}); ............... } (gdb) run 2019-07-15 11:47:32.396184: Sanity check socket connection and terminate it when it is inactive ............. pure virtual method called terminate called without an active exception Program received signal SIGABRT, Aborted. (gdb) backtrace #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51 #1 0x00007ffff7a24801 in __GI_abort () at abort.c:79 #2 0x00007ffff5565957 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #3 0x00007ffff556bab6 in ?? () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #4 0x00007ffff556baf1 in std::terminate() () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #5 0x00007ffff556c8bf in __cxa_pure_virtual () from /usr/lib/x86_64-linux-gnu/libstdc++.so.6 #6 HandleReadHeader(boost::system::error_code const&, unsigned int) () #7 0x00007ffff679a116 in boost::asio::detail::read_op<boost::asio::ssl::stream<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> > >, boost::asio::mutable_buffers_1, boost::asio::detail::transfer_all_t, HandleReadBody(boost::system::error_code const&, unsigned int)::{lambda(boost::system::error_code const&, unsigned int)#1}>::operator()(boost::system::error_code const&, unsigned long, int) () #8 0x00007ffff6799c20 in boost::asio::ssl::detail::io_op<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >, boost::asio::ssl::detail::read_op<boost::asio::mutable_buffers_1>, boost::asio::detail::read_op<boost::asio::ssl::stream<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> > >, boost::asio::mutable_buffers_1, boost::asio::detail::transfer_all_t, HandleReadBody(boost::system::error_code const&, unsigned int)::{lambda(boost::system::error_code c---Type <return> to continue, or q <return> to quit--- onst&, unsigned int)#1}> >::operator()(boost::system::error_code, unsigned long, int) () #9 0x00007ffff679b547 in boost::asio::detail::reactive_socket_recv_op<boost::asio::mutable_buffers_1, boost::asio::ssl::detail::io_op<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> >, boost::asio::ssl::detail::read_op<boost::asio::mutable_buffers_1>, boost::asio::detail::read_op<boost::asio::ssl::stream<boost::asio::basic_stream_socket<boost::asio::ip::tcp, boost::asio::stream_socket_service<boost::asio::ip::tcp> > >, boost::asio::mutable_buffers_1, boost::asio::detail::transfer_all_t, HandleReadBody(boost::system::error_code const&, unsigned int)::{lambda(boost::system::error_code const&, unsigned int)#1}> > >::do_complete(boost::asio::detail::task_io_service*, boost::asio::detail::task_io_service_operation*, boost::system::error_code const&, unsigned long) () #10 0x000055555559f5c0 in boost::asio::detail::task_io_service::do_run_one(boost::asio::detail::scoped_lock<boost::asio::detail::posix_mutex>&, boost::asio::detail::task_io_service_thread_info&, boost::system::error_code const&) () #11 0x000055555559f747 in boost::asio::detail::task_io_service::run(boost::system::error_code&) ()

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Useful Release Notes
by James E. King III 13 Jul '19

13 Jul '19

I'd suggest we make sure our release notes are useful to end users; I found some examples that are in the 1.71 that are not useful when reading the notes: * [phrase library..[(a)/libs/flyweight/index.html Flyweight]:] * Maintenance work. * [phrase library..[@/libs/poly_collection/ PolyCollection]:] * Maintenance work. Thanks, Jim

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meeting today
by Robert Ramey 12 Jul '19

12 Jul '19

I was impressed with your presentation today. you can find current renderings at this link: https://we.tl/t-TDoBHgw9AF Robert Ramey

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The out_ptr review is now over
by Zach Laine 11 Jul '19

11 Jul '19

Thanks to all that participated. A review result with be posted sometime in the next couple of weeks (the upcoming C++ standards meeting next week will delay it a bit). Zach

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