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Boost.Fiber mini-review May 23 - June 1
by Nat Goodspeed 02 Jun '16

02 Jun '16

Hi all, The Boost.Fiber candidate library by Oliver Kowalke begins a mini-review today, Monday May 23, which will close Wednesday June 1. It was last reviewed in September 2015; the verdict at that time was "not yet." Oliver has been working steadily to address review comments and to improve the library in other ways, and has brought the library back for mini-review. The updated documentation is here: http://olk.github.io/libs/fiber/doc/html/index.html The code is on the master branch of this repository: https://github.com/olk/boost-fiber/tree/master I believe it is Oliver's intention to respond to review feedback on the develop branch, leaving the master branch stable during the review. I will monitor reviews and discussion on both the boost-users@ list and the boost@ developers' list. Please include at least "fiber" and "review" in the subject line of your mail, e.g. by replying to this message. (Please reply to only ONE list, however.) I will also check the Boost Library Incubator for Fiber reviews: http://rrsd.com/blincubator.com/bi_library/fiber/?gform_post_id=859 though I check that less frequently than email. Please do remember to state in your review whether you think the library should be accepted as a Boost library. Thank you for your interest and your feedback! ----------------------------------------------------- Here follows a synopsis of issues raised during the September 2015 review: Cross-thread fiber migration: Evidently the community strongly desires the ability to transfer a suspended fiber from one thread to another. Now supported, with documentation. Cross-thread migration support implies a requirement to document the thread safety requirements of the customization API. Addressed. Standard required timing specifications: meet (30.2.4 Timing specifications [thread.req.timing]). Addressed. Adapt one or more existing test suites for thread facilities to validate the correctness of the Fiber library's synchronization constructs. The requester clarified in private mail that I misstated his suggestion: he wanted Oliver to review one or more such test suites to discover the kinds of issues that can arise with thread synchronization constructs. He has professed himself satisfied with the current state of the Fiber library's synchronization constructs. std::chrono support: ensure that wait_until() can accept any supported time_point specialization. Addressed. C++11 compatibility. Addressed. Document that this_fiber::yield() (et al.) are valid from main(), or in general from a thread function, as well as from explicitly-launched fibers. Addressed. Make shared_state lock requirements explicit: for example, make mark_ready_and_notify_() accept a std::unique_lock<>& (or &&) to force its caller to provide one. Addressed. Avoid holding mutex during condition_variable::notify_*() calls. Addressed. packaged_task must not decay-copy its task arguments. Addressed. Align fibers::async() signature, result description and invoke_helper implementation with std::async(). Avoid returning std::move(...). Addressed. Wait list implementation: try an intrusive linked list of fiber_context objects. Addressed. Avoid sleeping thread when no fibers are ready -- block on external event. Better handling of waiting tasks (decentralized wait queues?). Addressed. Optimization to resume awakened fiber on the thread that awakens it. Hooks provided. Template redundancy: eliminate duplication between specializations for T, T& and void. The future, shared_future, shared_state, promise and task_object templates were specifically cited. Addressed. Leverage predicate-based condition::wait() overload internally. Addressed. Nested schedulers: make schedulers be schedulable entities themselves. Not implemented. Improve robustness of `promise' handling in Asynchronous Callbacks documentation. Avoid overconfident remarks about it. Addressed. Fix Note overstating the requirements on condition_variable::wait(). Addressed.

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[optional] using name boost::in_place -- need your opinion/advice
by Andrzej Krzemienski 30 May '16

30 May '16

Hi Everyone, I have stumbled upon a problem that I do not know how to address. I would like to seek an advice from the people in this list. I am trying to make boost::optional resemble std::optional (where it is reasonably easy to achieve). std::optional has this nice and useful "placement" constructor: std::optional<std::mutex> m {std::in_place}; std::in_place is a tag type, that instructs std::optional to create an object using placement-new syntax, from the provided arguments (zero in the example), without incurring any move construction. I cannot easily copy 1-to-1 this solution, because in namespace boost name in_place is reserved for the in-place factories: http://www.boost.org/doc/libs/1_61_0/libs/utility/in_place_factories.html I could simply go with a different name for a tag, but something tells me it would introduce an unnecessary complications for users that want to migrate from one optional to another. I could hack in-place factories so that they can also be used as a tag, although, I am not sure it is doable in a type-safe manner, and if it would not confuse people to have this boost::in_place do a number of different things. I could use a different namespace, but again, this might look surprising.I am a bit torn. I wonder if anyone here needed to face a similar problem, and if you can think of an elegant solution. Thanks, &rzej

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[Boost.Test][Boot.Timer v2] header only boost.test conflicts with Boot.Timer V2
by Tan, Tom (Shanghai) 30 May '16

30 May '16

This following simple snippet would yield an error with visual studio 2015 for both boost1.60.61: boost/timer/timer.hpp(32): error C2757: 'timer': a symbol with this name already exists and therefore this name cannot be used as a namespace name // compiled with cl.exe /EHsc #define BOOST_TEST_MODULE test #include <boost/test/included/unit_test.hpp> #include <boost/timer/timer.hpp> The following variants are ok // compiled with cl.exe /EHsc #define BOOST_TEST_MODULE test #include <boost/test/unit_test.hpp> #include <boost/timer/timer.hpp> Or // compiled with cl.exe /EHsc #define BOOST_TEST_MODULE test #include <boost/test/included/unit_test.hpp> #include <boost/timer.hpp> It looks like Boost.Test is relying on boost.timer v1, which is deprecated in documentation and conflict with V2.

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[boost.timer v2] auto_cpu_timer does not compile
by Tan, Tom (Shanghai) 29 May '16

29 May '16

This following snippet generates an error with VS2015 both fo 1.60&1.61: libboost_timer-vc140-mt-s-1_61.lib(cpu_timer.obj) : error LNK2019: unresolved external symbol "public: static class boost::chrono::time_point<class boost::chrono::steady_clock,class boost::chrono::duration<__int64,class boost::ratio<1,1000000000> > > __cdecl boost::chrono::steady_clock::now(void)" (?now@steady_clock@chrono@boost@@SA?AV?$time_point@Vsteady_clock@chrono@boost@@V?$duration@_JV?$ratio@$00$0DLJKMKAA@@boost@@@23@@23@XZ) referenced in function "public: struct boost::timer::cpu_times __cdecl boost::timer::cpu_timer::elapsed(void)const " (?elapsed@cpu_timer@timer@boost@@QEBA?AUcpu_times@23@XZ) // compile with cl.exe /EHSc #include <boost/timer/timer.hpp> int main() { boost::timer::auto_cpu_timer t; } What's interesting is that uncommenting line #14 in file boost/timer/timer.hpp would get rid of this error. - Why is there such a line but commented out there? - Is there a better way to get it through without modifying this file - the binary is downloaded from sourceforge, not a custom build. - Thanks.

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Re: [boost] Boost.Fiber mini-review May 23 - June 1
by Bjorn Reese 28 May '16

28 May '16

On 05/23/2016 06:20 PM, Nat Goodspeed wrote: > Please do remember to state in your review whether you think the > library should be accepted as a Boost library. Yes, I vote for unconditional acceptance of Boost.Fiber. I did not participate in the formal review (due to time constraints), so I am not going to address the individual issues. I happened to have studied Boost.Fiber recently because I came across limitations of the inter-coroutine interaction in Boost.Coroutine, and Boost.Fiber addresses these limitations rather nicely. I especially like the message passing channels, which makes Boost.Fiber an obvious choice for building a coroutine-based actor framework. The only finding I have is that several Boost.Fiber headers include detail headers from Boost.Context. While this is not a problem per se (because Oliver is the maintainer of both libraries), it may be an idea to consider if these detail headers should be made public.

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[iterator] strided, recursive variants
by Jeremy Murphy 28 May '16

28 May '16

Dear Boosters, I was wondering why a strided iterator has not made it into the Boost.Iterator library? There is a strided range in Boost.Range based on a private implementation of such an iterator, and Boost.Compute has their own implementation too. Just an untied loose end? On a related note, what about variants of such iterators that work in recursive algorithms? That is, if you stride a strided iterator, existing implementations will keep nesting the stride type, which the compiler fails to do recursively because there is no stopping criterion. So I wrote a variant of strided iterator that when you stride a strided iterator, it just multiplies the two strides together and takes the base pointer type from the original strided iterator. I assume some of the other iterator adaptors are limited in the same way. Anyway, it's no big deal to me, but I just thought I'd canvas whether that's something people (especially the maintainers) are interested in? Cheers. Jeremy

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compiling mysql-5.7.12, cannot use DTRACE
by Mariano Apilado 26 May '16

26 May '16

Hi, I get the following error when compiling mysql-5.7.12 on Nexenta 4.0.4 OS ( Formerly known as Open Solaris / Illumos ). To temporarily bypass this problem, I chose not to use DTRACE with the compiler options. However, it should be fixed to use DTRACE. # cmake -DENABLE_DTRACE=0 Thanks and Regards,Mariano [ 15%] Linking CXX static library libmysys_ssl.a cd /usr/local/mysql-5.7.12/mysys_ssl && /usr/local/bin/cmake -P CMakeFiles/mysys_ssl.dir/cmake_clean_target.cmake cd /usr/local/mysql-5.7.12/mysys_ssl/CMakeFiles/mysys_ssl.dir && /usr/local/bin/cmake -DDTRACE=/usr/sbin/dtrace -DOUTFILE=/usr/local/mysql-5.7.12/mysys_ssl/CMakeFiles/mysys_ssl.dir/mysys_ssl_dtrace.o -DDFILE=/usr/local/mysql-5.7.12/include/probes_mysql.d -DDTRACE_FLAGS=-64 -DDIRS=. -DTYPE=STATIC_LIBRARY -P /usr/local/mysql-5.7.12/cmake/dtrace_prelink.cmake dtrace: failed to link script /usr/local/mysql-5.7.12/include/probes_mysql.d: No probe sites found for declared provider cd /usr/local/mysql-5.7.12/mysys_ssl && /usr/local/bin/cmake -E cmake_link_script CMakeFiles/mysys_ssl.dir/link.txt --verbose=1 /usr/bin/ar qc libmysys_ssl.a CMakeFiles/mysys_ssl.dir/crypt_genhash_impl.cc.o CMakeFiles/mysys_ssl.dir/mf_tempdir.cc.o CMakeFiles/mysys_ssl.dir/my_default.cc.o CMakeFiles/mysys_ssl.dir/my_getopt.cc.o CMakeFiles/mysys_ssl.dir/my_aes.cc.o CMakeFiles/mysys_ssl.dir/my_sha1.cc.o CMakeFiles/mysys_ssl.dir/my_sha2.cc.o CMakeFiles/mysys_ssl.dir/my_md5.cc.o CMakeFiles/mysys_ssl.dir/my_rnd.cc.o CMakeFiles/mysys_ssl.dir/my_murmur3.cc.o CMakeFiles/mysys_ssl.dir/my_aes_yassl.cc.o /usr/bin/ranlib libmysys_ssl.a cd /usr/local/mysql-5.7.12/mysys_ssl && /usr/bin/ar r /usr/local/mysql-5.7.12/mysys_ssl/libmysys_ssl.a /usr/local/mysql-5.7.12/mysys_ssl/CMakeFiles/mysys_ssl.dir/mysys_ssl_dtrace.o ar: cannot open /usr/local/mysql-5.7.12/mysys_ssl/CMakeFiles/mysys_ssl.dir/mysys_ssl_dtrace.o: No such file or directory ar: /usr/local/mysql-5.7.12/mysys_ssl/CMakeFiles/mysys_ssl.dir/mysys_ssl_dtrace.o not found gmake[2]: *** [mysys_ssl/libmysys_ssl.a] Error 1 gmake[2]: *** Deleting file `mysys_ssl/libmysys_ssl.a' gmake[2]: Leaving directory `/usr/local/mysql-5.7.12' gmake[1]: *** [mysys_ssl/CMakeFiles/mysys_ssl.dir/all] Error 2 gmake[1]: Leaving directory `/usr/local/mysql-5.7.12’ gmake: *** [all] Error 2

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Call for Papers for Meeting C++ 2016 ends on Friday night!
by Jens Weller 25 May '16

25 May '16

Hello Boost Community! a short reminder, that the deadline is coming up for submitting your talk to this years Meeting C++ conference! Meeting C++ 2016 Page: http://meetingcpp.com/index.php/mcpp2016.html Talk submission page: https://meetingcpp.com/mcpp/submittalk/ thanks, Jens Weller

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Error while compiling mysql-5.7.12 /usr/xpg4/include/term.h:596: error: conflicting types for ‘tgoto’
by Mariano Apilado 25 May '16

25 May '16

Hi, I get the following error when compiling mysql-5.7.12 on Nexenta 4.0.4 OS ( Formerly known as Open Solaris / Illumos ). In order to temporarily bypass this problem, I commented out. However, this is not the solution. /usr/local/mysql-5.7.12/cmd-line-utils/libedit/terminal.c:60: /* *#ifdef HAVE_CURSES_H *#include <curses.h> *#elif HAVE_NCURSES_H *#include <ncurses.h> *#endif */ Thanks and Regards,Mariano Error: [ 4%] Building C object cmd-line-utils/libedit/CMakeFiles/edit.dir/terminal.c.o cd /usr/local/mysql-5.7.12/cmd-line-utils/libedit && /usr/bin/gcc -DHAVE_CONFIG_H -D_FILE_OFFSET_BITS=64 -D_POSIX_PTHREAD_SEMANTICS -D_PTHREADS -D_REENTRANT -D__EXTENSIONS__ -I/usr/local/mysql-5.7.12/cmd-line-utils/libedit -I/usr/local/mysql-5.7.12/include -I/usr/local/mysql-5.7.12/extra/rapidjson/include -I/usr/local/mysql-5.7.12/libbinlogevents/include -I/usr/local/mysql-5.7.12/libbinlogevents/export -I/usr/xpg4/include -m64 -O3 -g -fabi-version=2 -fno-omit-frame-pointer -fno-strict-aliasing -DDBUG_OFF -fPIC -m64 -lstdc++ -R'RIGIN/../lib' -R/usr/lib/amd64 -o CMakeFiles/edit.dir/terminal.c.o -c /usr/local/mysql-5.7.12/cmd-line-utils/libedit/terminal.c In file included from /usr/xpg4/include/curses.h:43, from /usr/local/mysql-5.7.12/cmd-line-utils/libedit/terminal.c:60: /usr/xpg4/include/term.h:596: error: conflicting types for ‘tgoto’ /usr/local/mysql-5.7.12/cmd-line-utils/libedit/sys.h:137: note: previous declaration of ‘tgoto’ was here gmake[2]: *** [cmd-line-utils/libedit/CMakeFiles/edit.dir/terminal.c.o] Error 1 gmake[2]: Leaving directory `/usr/local/mysql-5.7.12' gmake[1]: *** [cmd-line-utils/libedit/CMakeFiles/edit.dir/all] Error 2 gmake[1]: Leaving directory `/usr/local/mysql-5.7.12’ gmake: *** [all] Error 2

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Having problems installing mysql 5.7.12 with boost ELF 32 bit, wrong ELF Class
by Mariano Apilado 25 May '16

25 May '16

Hi, I get the following error when compiling mysql-5.7.12 on Nexenta 4.0.4 OS ( Formerly known as Open Solaris / Illumos ). How do I fix the compile options or get the necessary files required to make the compile successful? Thanks and Regards, Mariano The files libboost_system.so and libboost_chrono.so are the wrong ELF class: ELFCLASS32. root@nex-01-test:/volumes# file /root/boost_1_59_0/stage/lib/libboost_system.so /root/boost_1_59_0/stage/lib/libboost_system.so: ELF 32-bit LSB dynamic lib 80386 Version 1, dynamically linked, not stripped, no debugging information available root@nex-01-test:/volumes# file /root/boost_1_59_0/stage/lib/libboost_system.so /root/boost_1_59_0/stage/lib/libboost_system.so: ELF 32-bit LSB dynamic lib 80386 Version 1, dynamically linked, not stripped, no debugging information available Error Message: [ 95%] Linking CXX executable ../mysqlpump cd /root/mysql-5.7.12/client/dump && /usr/local/bin/cmake -E cmake_link_script CMakeFiles/mysqlpump.dir/link.txt --verbose=1 /usr/bin/g++ -w -fpermissive -m64 -Wall -Wextra -Wformat-security -Wvla -Woverloaded-virtual -Wno-unused-parameter -O3 -g -fabi-version=2 -fno-omit-frame-pointer -fno-strict-aliasing -DDBUG_OFF -R'$ORIGIN/../lib' -R/usr/lib/amd64 CMakeFiles/mysqlpump.dir/program.cc.o -o ../mysqlpump libmysqlpump_lib.a -lboost_system -lboost_chrono ../base/libclient_base.a ../../libmysql/libmysqlclient.a -lsocket -lnsl -lm ../../extra/liblz4_lib.a ld: fatal: file /root/boost_1_59_0/stage/lib/libboost_system.so: wrong ELF class: ELFCLASS32 ld: fatal: file /root/boost_1_59_0/stage/lib/libboost_chrono.so: wrong ELF class: ELFCLASS32 ld: fatal: file processing errors. No output written to ../mysqlpump collect2: ld returned 1 exit status gmake[2]: *** [client/mysqlpump] Error 1 gmake[2]: Leaving directory `/root/mysql-5.7.12' gmake[1]: *** [client/dump/CMakeFiles/mysqlpump.dir/all] Error 2 gmake[1]: Leaving directory `/root/mysql-5.7.12’ gmake: *** [all] Error 2

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