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[release] Boost 1.74.0 beta 1 released
by Marshall Clow 16 Jul '20

16 Jul '20

Boost release 1.74.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.74.0.beta.1/source/> The SHA256 checksums are as follows: 577a6b575ff2c227e14cce1b929c73d969475e58f3d2ab2901ad234f773bbd12 boost_1_74_0_b1.7z ba09c72dc848e7c0904922967014d853897b5a634926c910cc3b1fd627c31605 boost_1_74_0_b1.tar.bz2 2ccdc39efa076822cf1b359f9449f9d07707f3e27a18b393297b25885a9ff45b boost_1_74_0_b1.tar.gz c267c450166e040a374eaddab5e583cef09f6c3fe96a4db826172d0315c38dd5 boost_1_74_0_b1.zip For details of what's in the release, see < https://www.boost.org/users/history/version_1_74_0.html>. Please download the beta, give it a try, and report any problems you encounter. Issues that were found during the beta release process and will be fixed for the final 1.74.0 release: * The Boost.STLInterfaces documentation was left out of the beta. * Some of the Boost.Geometry documentation files have very long names; this could cause problems on platforms (like Windows) with shorter limits on path lengths. * There is a compile error in Boost.ASIO when compiling with 32-bit MSVC-14.2 with BOOST_BEAST_NO_TS_EXECUTORS. Thanks, -- The Boost Release Team

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[release] Boost 1.74.0 Beta 1 Release Candidate 1
by Marshall Clow 14 Jul '20

14 Jul '20

The release candidates for the first 1.74.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.74.0.beta.1/source/ The release notes are not yet available. The SHA256 checksums are as follows: 577a6b575ff2c227e14cce1b929c73d969475e58f3d2ab2901ad234f773bbd12 boost_1_74_0_b1_rc1.7z ba09c72dc848e7c0904922967014d853897b5a634926c910cc3b1fd627c31605 boost_1_74_0_b1_rc1.tar.bz2 2ccdc39efa076822cf1b359f9449f9d07707f3e27a18b393297b25885a9ff45b boost_1_74_0_b1_rc1.tar.gz c267c450166e040a374eaddab5e583cef09f6c3fe96a4db826172d0315c38dd5 boost_1_74_0_b1_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 Boost Release Managers

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bjam using boost-1.77
by Cho-Kuen Ng 11 Jul '20

11 Jul '20

I used to use a very old version of bjam and wanted to switch to the most recent version 1.77. When I use the new bjam, I encounter the following problems. o I have 2 projects with the same id, the error message is error: at nml/unit_test/Jamfile:1 error: Attempt to redeclare already registered project id '/test'. error: Original project: error: Name: Jamfile</Users/cho/work/distmesh/unit_test> error: Module: Jamfile</Users/cho/work/distmesh/unit_test> error: Main id: /test error: File: distmesh/unit_test/Jamfile error: Location: distmesh/unit_test error: New project: error: Module: Jamfile</Users/cho/work//nml/unit_test> error: File: nml/unit_test/Jamfile error: Location: nml/unit_test After I changed the id in one project, the errors disappeared. o I do bjam again, I have this error /Users/cho//doc/boost/boost_1_73_0/tools/build/src/build/generators.jam:1127: in ensure-type from module generators error: target { PNCDF_Variable.C. } has no type Once I changed the C extension to cpp, the error disappeared. I don't have these problems using the old bjam. Are there syntax changes in the Jamfile? Please help. Thanks, Cho

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[InterProcess] receiving notification when an item is added to the message queue
by Sean Farrow 11 Jul '20

11 Jul '20

Good afternoon, I am looking to use the message queue in the Interprocess library to communicate between two Windows processes. I was wondering whether there was an in-built mechanism to signal to the process reading from the queue that a message is available for consumption. If there isn't anything in-built, I was wondering what the best way to do this is and whether anybody has any working sample code they would be willing to share? Any help appreciated as always. Kind regards Sean.

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Re: [Boost-users] Boost ABI/Linkage of clang vs g++
by DV Henkel-Wallace 10 Jul '20

10 Jul '20

> Date: Thu, 9 Jul 2020 16:44:58 +0100 > From: <pbristow(a)hetp.u-net.com> > > Does b2 -debug-configuration help? > > https://boostorg.github.io/build/manual/master/index.html section 3.3 configuration > > ? > You can use the --debug-configuration option to find which configuration files are actually loaded. Thanks, Paul, this helped me figure out a colleague had modified a .jam file and checked it in. -d

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[ASIO] Using boost::asio::thread_pool with sockets without boost::asio::io_context
by Aniruddh Agarwal 09 Jul '20

09 Jul '20

Hello, One strategy to load-balance I/O processing across multiple threads is to use a single io_context object for multiplexing and to call io_context::run from all threads in the thread pool. This can be set up by, for example, defining a type which holds a vector of threads, all of which are calling io_context::run. My first question is: is this approach of calling io_context::run from several threads somewhat equivalent to using boost::asio::thread_pool as the default execution context and not (explicitly, at least) creating a boost::asio::io_context object at all? Somewhat more specifically, is it safe to define TCP sockets/acceptors/etc. with execution contexts set to a boost::asio::thread_pool instead of io_context, and will that work as expected (i.e., as a single io_context object scheduling tasks out to several threads calling io_context::run would)? -Ani

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Concurrency support in iostream mapped_file_source
by Lloyd 03 Jul '20

03 Jul '20

Hi, Does boost iostream mapped_file_source support concurrent read from multiple threads? What is the best way to implement concurrent read on a performance sensitive application? The file is a read only one and its size is in gigabytes/terabytes Thanks, Lloyd

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[serialization] Backward compatibility problem with 1:73
by Kai Benndorf 25 Jun '20

25 Jun '20

Hi all, we are using boost serialization for writing and reading data and just switched from boost 1:67 to boost 1:73. We now cannot read back the data written with boost 1:67 or prior. We get an archive_exception::input_stream_error exception. Examining the files shows the difference. The old files are starting with 22 serialization::archive 16 The new files are missing this data. Removing it from the files enabled the reading with boost 1:73. But strangely, if trying a small example program (the gps example from the documentation) also boost 1:73 produces this data: 22 serialization::archive 18 Any idea what has changed in between these versions and could cause this problem? Thanks in advance for any hint. Our application uses an own derived archive class. Maybe I have to changed something there? Best regards Kai Benndorf ---------------------------------------------------------------- Kai Benndorf E-Mail: kai.benndorf(a)web.de Zur Maibolte 44 MOBILE: 0151 55627946 32657 Lemgo WORK: 05251 150623 Germany PHONE: 05261 14465 ----------------------------------------------------------------

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[boost][mp11][GIL]
by Debabrata Mandal 18 Jun '20

18 Jun '20

Hi, I am trying to implement a histogram class that will be able to store tuples of any data type. Most likely, I chose std::tuple for the job. So, in brief I used std::tuple as the key type in an unordered_map. I used boost::hash_value to supply the hasher in place of std::hash in the third template argument to unordered_map. Now, fast forwarding to my problem, I want to be able to provide a sub-histogram based on a few axes of the histogram. The code below, quite similar to what I want, refuses to work with msvc-14.0 (coming to it shortly). ----Sample Code---- #include <boost/mp11.hpp> template<typename... T> struct histogram { using type_list = boost::mp11::mp_list<T...>; template<std::size_t... D> void d() { // Error in below line histogram<boost::mp11::mp_at_c<type_list, D>...> f; } }; int main() { histogram<int, int, int, int> f; f.d<1,2>(); return 0; } ---END--- So, msvc-14.0 gives the error (after tracing to the last function call in stack) at the position specified above. The error message which is coming from the AppVeyor logs (since I do not have msvc-14.0) ... C:\projects\boost-root\boost/mp11/utility.hpp(53): error C2971: 'boost::mp11::detail::mp_if_c_impl': template parameter 'C': 'C': a variable with non-static storage duration cannot be used as a non-type argument C:\projects\boost-root\boost/mp11/utility.hpp(38): note: see declaration of 'boost::mp11::detail::mp_if_c_impl' C:\projects\boost-root\boost/gil/histogram.hpp(247): note: see declaration of 'C' ... I am not sure if the issue is with mp11 or the msvc-14.0, but I did find some references which claim a similar issue with the latter case. This links <https://developercommunity.visualstudio.com/content/problem/719235/erroneou…> to a very similar case of the error C2971 which seems to be fixed in the future releases. Also, the code above compiles fine with GCC and Clang. Any comments or suggestions on this are most welcome. Thanks, Deb GSOC 2020 student in Boost.GIL

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Re: [Boost-users] [boost] [review] [text] Text formal review
by Vinnie Falco 17 Jun '20

17 Jun '20

On Fri, Jun 12, 2020 at 10:36 AM Rainer Deyke via Boost <boost(a)lists.boost.org> wrote: > String layer: overall, a solution looking for a problem. I created boost::json::string to use instead of std::string for a couple of reasons: 1. It uses a type-erased, reference counted memory resource instead of Allocator template parameter 2. The class is laid out a certain way to greatly minimize its size 3. The class layout is optimized to keep the size of the enclosing variant (the JSON DOM value type) small 4. The API is the same for all C++ versions (unlike std::string) 5. It is not a class template I would like to know what are the exact _technical_ benefits of Boost.Text's String layer, beyond "because I don't like std::string" Thanks

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