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CMake Announcement from Boost Steering Committee
by Jon Kalb 18 Jul '17

18 Jul '17

The libraries produced by the Boost community have had a greater impact on the way that the C++ community writes code than any other library implementation. The focus of the Boost community will always be on the libraries, but it is undeniable that we are dependent on and often limited by the infrastructure of our trade. Years ago, the move to Git was contentious; yet, it was required to improve development. In a similar vein our build system has become an impediment for many developers and users, existing and prospective. Therefore, we, the Steering Committee, announce to the Boost community our desire and intent to move Boost’s build system to CMake for users and developers alike. We are soliciting comments and proposals from the community to guide the process and the goals. Our desire is that the community can come to consensus by the end of the calendar year with a vision of supporting users and developers. We understand that the actual process of achieving the end goal will be long, time consuming, and not without its share of conflict. We also recognize that the Boost community is comprised of bright and passionate individuals that are eager to get involved and help get work done. The members of the Steering Committee have been encouraged by the discussions and activity surrounding CMake on the mailing lists over the years and know that many people have voiced visions. We hope that each of you rejoins the discussion to support this initiative and contributes to the common goal of improving Boost’s integration into the broader C++ ecosystem. For the Boost Steering Committee, Jon Kalb, Chair jonkalb(a)boost.org

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Re: [Boost-users] CMake Announcement from Boost Steering Committee
by Oliver Kowalke 18 Jul '17

18 Jul '17

Cmake file for boost.context is missing support for segmented stack (split-stack), valgrind ...? Is the Cmake port is not complete?

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Boost 1.65.0 Beta 1
by Marshall Clow 16 Jul '17

16 Jul '17

Boost release 1.65.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.65.0.beta.1/source/> The SHA256 checksums are as follows: d54d29568c4e4933cbfe40a292b6cb84a7f68121e34f6a83f7d0f7c652b6b2d8 boost_1_65_0_beta1.7z 092676557513e992347d30dd0cd058fb8af2a401e5da4f4413f5b577852d726b boost_1_65_0_beta1.tar.bz2 31fa3c807e2205e18f7d5c74f77f540677f7b0937af1e37f595c137e1e87bf84 boost_1_65_0_beta1.tar.gz 83c8d8b76fa9591572226a1a49fd191d76db3011b52b907cbbc8d37d46213bd2 boost_1_65_0_beta1.zip Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

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Boost Regex Back Reference Issue
by Nick 14 Jul '17

14 Jul '17

According to the Boost documentation for Back references (http://www.boost.org/doc/libs/1_64_0/libs/regex/doc/html/boost_regex/syntax…) which seems to be the same at least from 1.37 - 1.64. Quoting a piece of the documentation: ----- For example the expression: ^(a*).*\1$ Will match the string: aaabbaaa But not the string: aaabba ----- I'm finding two issues with the example cited. 1. It seems to me that the example of the string which should not match, should actually match. Ultimately, shouldn't the engine match the marked sub-expression with the first 'a' in order to satisfy the backreference? I tested this example with Oniguruma and with PHP's PCRE and they both matched the string noted here to not match. But also, since the marked sub-expression is (a*) then I wonder what the behavior would be if it couldn't make a match on 'a', since the '*' will allow for zero matches. In fact, it seems like everything in the pattern is effectively "optional" due to the '*' operator. I'm a novice with Perl, but unless I made a mistake, it will match unconditionally: print "It matches\n" if "aaabba" =~ /^(a*).*\1$/; It matches print "It matches\n" if "aaabbac" =~ /^(a*).*\1$/; It matches print "It matches\n" if "" =~ /^(a*).*\1$/; It matches print "It matches\n" if "x" =~ /^(a*).*\1$/; It matches print "It matches\n" if "xyz" =~ /^(a*).*\1$/; It matches print "It matches\n" if "123" =~ /^(a*).*\1$/; It matches 2. The other issue is that when I try this example with the string which is posted to not match, the Boost regex engine runs for a while and ultimately crashes with a memory error. (seems like it might be an endless loop of some sort). Is that a bug? Nick

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boost::unordered_map takes too long when I have only two elements in it
by Ram 14 Jul '17

14 Jul '17

Hi, I am using a boost::unordered_set but I sometimes have just two elements in it. It takes a long time then. Is it wrong if I have too few elements? Thanks, Ram

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rational - 1.64 version shear?
by Nicholas Devenish 14 Jul '17

14 Jul '17

With boost/rational.hpp, the code: boost::rational<int> a{1}; long b{1}; auto c{a * b}; Works fine up to 1.63.0, but fails to compile in 1.64+ on the multiplication with "error: invalid operands to binary expression". This seems to be due to some restructuring that changed the way multiplications are declared, which (as far as I can tell), meant the operation declaration became conditional on number of representable digits. This breaking change isn't listed on the release notes or the ::rational documentation, so I'm wondering if it was accidental and therefore a bug (whose behaviour might change), or a deliberate change to prevent downcasting and just undocumented? Nick (I've come onto a project stuck on 1.56 and trying to update it)

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⁨[process] problem with boost::process::on_exit
by Sandy Martel 14 Jul '17

14 Jul '17

The code below outputs: 1- child about to sleep for 2s 2- child about to sleep for 4s 3- child finish sleeping for 2s 6- sleep 4s child finished 5- child finish sleeping for 4s 4- sleep 2s child finished in a posix environment. I would expect the output to be in-order, looks like I get the wrong on_exit notification for the child processes I launch. Q: is this a bug or am I doing something wrong ? What is the correct way to get notified of specific process termination ? Regards, Sandy. code: #include <boost/process.hpp> #include <boost/asio.hpp> #include <thread> #include <iostream> int main( int argc, char **argv ) { if ( argc > 2 && strcmp( argv[1], "sleep" ) == 0 ) { auto s = atoi(argv[2]); std::cout << (s/2) << "- child about to sleep for " << s << "s" << std::endl; std::this_thread::sleep_for( std::chrono::seconds(s) ); std::cout << (s+1) << "- child finish sleeping for " << s << "s" << std::endl; return 0; } namespace bp = boost::process; boost::asio::io_service ios; // launch a child that will sleep for 2s auto c1 = bp::child( argv[0], "sleep", "2", ios, bp::on_exit( [](int, const std::error_code&) { std::cout << "4- sleep 2s child finished" << std::endl; }) ); // wait a bit, make sure the child startup for my test std::this_thread::sleep_for( std::chrono::milliseconds(10) ); // launch a child that will sleep for 4s auto c2 = bp::child( argv[0], "sleep", "4", ios, bp::on_exit( [](int, const std::error_code&) { std::cout << "6- sleep 4s child finished" << std::endl; }) ); // wait for the notifications ios.run(); }

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[serialization] "Archive" type turns into abstract class during save/load!
by r＠primef.actor 13 Jul '17

13 Jul '17

In a member load function function I call a static method that loads another archive file, i.e. something like this: ```c++ struct Bar; struct Foo { std::shared_ptr<Bar> data; template <class Archive> void load(Archive& archive, const unsigned /*version*/) { std::string key; archive >> key; data = Bar::loadSomewhere<Archive>(std::move(key)); } }; struct Bar { template <class Archive> std::shared_ptr<Bar> loadSomewhere(std::string key) { std::ifstream input(key); Archive ar(input); std::shared_ptr<Bar> bar(new Bar()); ar >> *bar; return bar; } }; ``` The problem is that `Bar::loadSomewhere` is passed a `boost::archive::polymorphic_iarchive`, while I invoke the serialization library with a `boost::archive::xml_iarchive`. This is an abstract class, so I can't instantiate it! So somewhere down the road the `xml_iarchive` is turned into a `polymorphic_iarchive`. I would like to prevent this from happening, because I instantiate an `Archive` object in the `Bar::loadSomewhere` function. How can I get around this problem?

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Re: [Boost-users] Boost 1.65.0 Beta 1 Release Candidate 2
by Matthieu Brucher 11 Jul '17

11 Jul '17

This happens a lot when people develop on gcc or visual studio and then try building with clang. Having a function and a class with the same name is bound to generate errors. So properly should be tagged as a bug. Le 11 juil. 2017 11:14 AM, "Raffi Enficiaud via Boost-users" < boost-users(a)lists.boost.org> a écrit : Le 11.07.17 à 02:14, Marshall Clow via Boost-users a écrit : The second release candidates for the 1.65.0 beta release are now > available at: > > > https://dl.bintray.com/boostorg/beta/1.65.0.beta.1/source/ > boost_1_65_0_beta1_rc2.7z > > https://dl.bintray.com/boostorg/beta/1.65.0.beta.1/source/ > boost_1_65_0_beta1_rc2.tar.bz2 > > https://dl.bintray.com/boostorg/beta/1.65.0.beta.1/source/ > boost_1_65_0_beta1_rc2.tar.gz > > https://dl.bintray.com/boostorg/beta/1.65.0.beta.1/source/ > boost_1_65_0_beta1_rc2.zip > > The SHA256 checksums are as follows: > > d54d29568c4e4933cbfe40a292b6cb84a7f68121e34f6a83f7d0f7c652b6b2d8 > boost_1_65_0_beta1_rc2.7z > 092676557513e992347d30dd0cd058fb8af2a401e5da4f4413f5b577852d726b > boost_1_65_0_beta1_rc2.tar.bz2 > 31fa3c807e2205e18f7d5c74f77f540677f7b0937af1e37f595c137e1e87bf84 > boost_1_65_0_beta1_rc2.tar.gz > 83c8d8b76fa9591572226a1a49fd191d76db3011b52b907cbbc8d37d46213bd2 > boost_1_65_0_beta1_rc2.zip > > > This RC contains a single fix to the stacktrace library. > > 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. > > Thanks! > > -- The release managers > Hi, I have this error during the build on OSX. Built with: ./b2 cxxflags="-std=c++11 -stdlib=libc++" linkflags="-stdlib=libc++" --without-log --layout=versioned install ...on 14200th target... common.mkdir bin.v2/libs/fiber/build/darwin-4.2.1/release/threading-multi common.mkdir bin.v2/libs/fiber/build/darwin-4.2.1/release/threading- multi/numa darwin.compile.c++ bin.v2/libs/fiber/build/darwin-4.2.1/release/threading- multi/numa/pin_thread.o libs/fiber/src/numa/pin_thread.cpp:23:10: warning: pin_thread() not supported [-W#pragma-messages] # pragma message "pin_thread() not supported" ^ 1 warning generated. darwin.compile.c++ bin.v2/libs/fiber/build/darwin-4.2.1/release/threading- multi/numa/topology.o libs/fiber/src/numa/topology.cpp:23:10: warning: topology() not supported [-W#pragma-messages] # pragma message "topology() not supported" ^ libs/fiber/src/numa/topology.cpp:27:14: error: use of undeclared identifier 'topology'; did you mean 'fibers::numa::topology'? std::vector< topology > topology() { ^~~~~~~~ fibers::numa::topology ./boost/fiber/numa/topology.hpp:38:21: note: 'fibers::numa::topology' declared here std::vector< node > topology(); ^ libs/fiber/src/numa/topology.cpp:27:14: error: template argument for template type parameter must be a type std::vector< topology > topology() { ^~~~~~~~ /Applications/Xcode8.1.app/Contents/Developer/Toolchains/Xco deDefault.xctoolchain/usr/bin/../include/c++/v1/vector:456:17: note: template parameter is declared here template <class _Tp, class _Allocator = allocator<_Tp> > ^ 1 warning and 2 errors generated. "g++" -ftemplate-depth-128 -O3 -Wall -dynamic -gdwarf-2 -fexceptions -Wno-inline -fPIC -arch x86_64 -std=c++11 -stdlib=libc++ -DBOOST_ALL_NO_LIB=1 -DBOOST_CONTEXT_DYN_LINK=1 -DBOOST_DISABLE_ASSERTS -DBOOST_FIBERS_DYN_LINK=1 -DBOOST_FIBERS_SOURCE -DBOOST_FILESYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/fiber/build/darwin-4.2.1/release/threading-multi/numa/topology.o" "libs/fiber/src/numa/topology.cpp" ...failed darwin.compile.c++ bin.v2/libs/fiber/build/darwin -4.2.1/release/threading-multi/numa/topology.o... _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org https://lists.boost.org/mailman/listinfo.cgi/boost-users

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Boost 1.65.0 Beta 1 Release Candidate 1
by Marshall Clow 09 Jul '17

09 Jul '17

The release candidates for the 1.61.0 release are now available at: https://dl.bintray.com/boostorg/beta/boost_1_65_0_beta1_rc1.7z https://dl.bintray.com/boostorg/beta/boost_1_65_0_beta1_rc1.tar.bz2 https://dl.bintray.com/boostorg/beta/boost_1_65_0_beta1_rc1.tar.gz https://dl.bintray.com/boostorg/beta/boost_1_65_0_beta1_rc1.zip The SHA256 checksums are as follows: cd7429340bb4aae38e0ad2e9f59c39e66335302c41577956123e55fc1e2a28ee boost_1_65_0_beta1_rc1.7z fda076f7b3c994524d9cd41926c72f4a9b7c017bef310a055956fdd0bed7c358 boost_1_65_0_beta1_rc1.tar.bz2 0d1473041f7a9fa9ce1e256c870cc52af6f98abf723cf4f1ac61c2b45f45d38a boost_1_65_0_beta1_rc1.tar.gz f45bbb75b84cdc0c66f8a571d77c518cfbac076d7a6fc7937c4812f0f242a792 boost_1_65_0_beta1_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. Thanks! -- The release managers

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