August 2014 - Boost - lists.preview.boost.org

[utility] string_ref construction from rvalue reference to string
by Андрей Давыдов 03 Aug '14

03 Aug '14

Hello, boost. Are the any reasonable cases when construction boost::string_ref from std::string && is desirable? I mean that usage string_ref in the following examples is totally wrong, but not for compiler: using std::string; using boost::string_ref; // 1 { auto ref = string_ref(string("abacaba") + string("upyachka")); std::cout << ref << std::endl; } // 2 { string very_long(1000000, 'a'); auto ref = string_ref(very_long + "b"); std::cout << ref << std::endl; } In practice it gets worse, because the first example example works (gcc 4.9.1) thanks to optimizations with short literals, I suspect, and the second example leads to segmentation fault, as expected. Those errors can be caught at compile time if class "basic_string_ref" defintion would contain lines like following: template<typename Allocator> basic_string_ref(std::basic_string<charT, traits, Allocator> &&) = delete; I cannot understant does it prevent any correct usage of string_ref? -- Andrey Davydov

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Hangs with Boost 1.56 on clang armhf
by Niall Douglas 03 Aug '14

03 Aug '14

I'm seeing consistent hangs of AFIO on Boost 1.56 on Ubuntu 14.04 LTS for clang armhf. GCC armhf works fine, so this is a clang armhf related issue. https://ci.nedprod.com/view/Boost.AFIO/job/Boost.AFIO%20Test%20POSIX_A RM_clang%203.4/10/console I talked to Ubuntu upstream about this, and I had the idea of trying the LLVM armhf binaries provided at http://llvm.org/releases/3.4.2/clang+llvm-3.4.2-armv7a-linux-gnueabihf .tar.xz as surely LLVM provide good binaries. Same problem - tests hang. I tried running a test manually and I get this: terminate called after throwing an instance of 'boost::thread_interrupted' terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively terminate called recursively Remember, this is identical code to any other Linux target, plus this works a-ok for GCC armhf. A quick backtrace with gdb reveals this: terminate called after throwing an instance of 'boost::thread_interrupted' [Thread 0xb5b76450 (LWP 12610) exited] Program received signal SIGABRT, Aborted. [Switching to Thread 0xb6376450 (LWP 12609)] __libc_do_syscall () at ../ports/sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:44 44 ../ports/sysdeps/unix/sysv/linux/arm/libc-do-syscall.S: No such file or directory. (gdb) bt #0 __libc_do_syscall () at ../ports/sysdeps/unix/sysv/linux/arm/libc-do-syscall.S:44 #1 0xb639f0fe in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56 #2 0xb63a1956 in __GI_abort () at abort.c:89 #3 0xb65377a8 in __gnu_cxx::__verbose_terminate_handler() () from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 #4 0xb65361c8 in ?? () from /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 Backtrace stopped: previous frame identical to this frame (corrupt stack?) What looks to be happening here is that thread cancellation, which works by having an exception thrown, appears to not be caught by the thread being cancelled for some odd reason. I don't have time to investigate this until maybe Saturday. I guess we'll just have to ship 1.56 and look into this for 1.57. Niall -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Re: [boost] [1.56.0] Release candidates available
by Eric Niebler 03 Aug '14

03 Aug '14

On 07/29/2014 02:44 PM, Boris Schäling wrote: > On Tue, 29 Jul 2014 19:06:43 +0200, Marshall Clow > <mclow.lists(a)gmail.com> wrote: > >> Release candidate files for 1.56.0 are available at >> http://boost.cowic.de/rc/ > > I get a compiler error with g++ 4.8.3 on Cygwin (64-bit): > > In file included from libs\system\src\error_code.cpp:19:0: > ./boost/system/detail/error_code.ipp: In member function ‘virtual > std::string > boost::system::{anonymous}::system_error_category::message(int) const’: > ./boost/system/detail/error_code.ipp:413:5: error: > ‘local_free_on_destruction’ is not a member of ‘boost::detail’ > detail::local_free_on_destruction lfod(lpMsgBuf); > ^ > > This looks like the bug Eric had reported at > <https://svn.boost.org/trac/boost/ticket/10137>. Crud. Beman, did a merge get missed? Eric

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Re: [boost] b2 headers is unreliable on 1.56 on Windows
by Matthew Musto 01 Aug '14

01 Aug '14

Nial, I found you need to run your cmd prompt as administrator before running b2 in order for the sym links to work correctly, otherwise you end up with hard links and the process fails 9 times out of 10. At least that is what I found on Win 8.1, -Matt From: Niall Douglas <s_sourceforge <at> nedprod.com> Subject: b2 headers is unreliable on 1.56 on Windows <http://news.gmane.org/find-root.php?message_id=53D91411.15683.55F433CE%40s%…> Newsgroups: gmane.comp.lib.boost.devel <http://news.gmane.org/gmane.comp.lib.boost.devel> Date: 2014-07-30 15:49:37 GMT (8 hours and 40 minutes ago) Anyone else found that b2 headers in 1.56 randomly misses things to hard link on Windows? If you run it four or five times it eventually hard links everything through monte-carlo, but it is a bit annoying. Niall -- ned Productions Limited Consultinghttp://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Boost logos on mailing list archives linking to non-boost pages instead of boost.org
by Curdeius Curdeius 01 Aug '14

01 Aug '14

Hi all, I have just spotted a curious detail on 3 Boost mailing lists. The logos (C++ Boost / Boost C++ libraries) point to web pages that are not affiliated in any way to boost. The concerned lists are: - http://lists.boost.org/boost-docs/ points to www [dot] boost [dot] com - http://lists.boost.org/boost-testing/ points to www [dot] boost [dot] com - http://lists.boost.org/geometry/ points to www [dot] osl [dot] iu [dot] edu I am not sure if this is the correct list to write to. If anyone knows what to do about it, please answer to the list or inform the correct person. Regards, Marek Kurdej

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Understanding Jam Files
by Axel Ismirlian 01 Aug '14

01 Aug '14

I have been working on boost for about a month now, but I still don't fully understand boost's build configuration very well. More specifically, I do not understand where the properties array gets filled in and where that data comes from. I saw the property.jam file which seems to refine the list of properties and take away unmet conditions, and bind dependencies. I also saw the property-set.jam file which creates property lists from raw properties, but where do the raw properties come from exactly? Does every property-set created come through this file? It would be very helpful if someone could point me in the right direction. Sincerely, -Axel

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synchorize or strand
by dd 01 Aug '14

01 Aug '14

Hi all, There is multi-threaded application which will access data containers at the same time. Which is the best choice between synchronization and strands. Thanks, dd

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