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From: "thomas.sanchz at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/60966] std::call_once sometime hangs Date: Mon, 28 Apr 2014 07:55:00 -0000 [thread overview] Message-ID: <bug-60966-4-qMkJU6uZi0@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-60966-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60966 --- Comment #4 from Thomas Sanchez <thomas.sanchz at gmail dot com> --- (In reply to Jonathan Wakely from comment #3) > > > N.B. the std::move in Manager::cancelConnection is redundant, the return > > > value from cancel_connection is already an rvalue. > > > > Yes, I know, the problem is I have some hard time to avoid doing this as it > > is more for me and what I expect the compiler to do or the semantics I want > > the code to have :) > > OK, but it makes the code worse. Here the compiler will elide the move > constructor (aka return value optimisation): > > auto future = cancel_connection(c); > > Whereas here the compiler cannot do that and must call a move constructor: > > auto future = std::move(cancel_connection(c)); I did not meant to say I should continue, far from here :) Thank for the notice! Anyway, I pushed the actual code in this branch: https://github.com/daedric/httpp/tree/bug-promise-test I was able to do a small test that can *sometimes* reproduce the bug: https://github.com/daedric/httpp/blob/bug-promise-test/tests/client/promise.cpp Since I was able to trigger the problem, here are what you asked for: >From the get side, (from here https://github.com/daedric/httpp/blob/bug-promise-test/src/httpp/http/client/Manager.cpp#L113) (gdb) print future $1 = { <std::__basic_future<void>> = { <std::__future_base> = {<No data fields>}, members of std::__basic_future<void>: _M_state = std::shared_ptr (count 2, weak 0) 0x805468 }, <No data fields>} (gdb) print promise $2 = { _M_future = std::shared_ptr (count 2, weak 0) 0x805468, _M_storage = std::unique_ptr<std::__future_base::_Result<void>> containing 0x805780 } (gdb) print &promise $3 = (std::promise<void> *) 0x7fffffffce90 >From the thread calling the pthread_once: #4 0x0000000000500d67 in std::promise<void>::set_value (this=0x7fffffffce90) at /usr/include/c++/4.8/future:1197 1197 _M_future->_M_set_result(std::move(__setter)); (gdb) print *this $4 = { _M_future = std::shared_ptr (count 2, weak 0) 0x805468, _M_storage = std::unique_ptr<std::__future_base::_Result<void>> containing 0x805780 } This is seems to be correct. This has been produced with commit: 850ebba9a72d102b54de6912e820889618a4f30d I'm testing now with the lambdas replaced :) http://reproducible.io/
next prev parent reply other threads:[~2014-04-28 7:55 UTC|newest] Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-04-25 13:57 [Bug libstdc++/60966] New: " thomas.sanchz at gmail dot com 2014-04-25 17:53 ` [Bug libstdc++/60966] " redi at gcc dot gnu.org 2014-04-25 18:36 ` redi at gcc dot gnu.org 2014-04-28 7:55 ` thomas.sanchz at gmail dot com [this message] 2014-04-28 8:09 ` thomas.sanchz at gmail dot com 2014-04-28 8:15 ` thomas.sanchz at gmail dot com 2014-04-28 8:22 ` redi at gcc dot gnu.org 2014-05-05 7:48 ` thomas.sanchz at gmail dot com 2014-05-05 15:16 ` redi at gcc dot gnu.org 2014-05-13 22:24 ` fawaka at gmail dot com 2014-05-14 1:58 ` hideaki.kimura at gmail dot com 2014-05-14 7:27 ` thomas.sanchz at gmail dot com 2014-05-14 10:43 ` redi at gcc dot gnu.org 2014-05-15 3:13 ` hideaki.kimura at gmail dot com 2014-05-15 21:05 ` redi at gcc dot gnu.org 2014-05-15 21:30 ` redi at gcc dot gnu.org 2014-05-15 22:02 ` hideaki.kimura at gmail dot com 2014-05-15 22:14 ` redi at gcc dot gnu.org 2014-05-15 22:55 ` redi at gcc dot gnu.org 2014-05-15 22:59 ` redi at gcc dot gnu.org 2014-05-15 23:39 ` redi at gcc dot gnu.org 2014-05-16 0:05 ` hideaki.kimura at gmail dot com 2014-05-16 0:15 ` redi at gcc dot gnu.org 2014-05-16 0:28 ` fawaka at gmail dot com 2014-05-16 7:18 ` redi at gcc dot gnu.org 2014-05-16 7:31 ` thomas.sanchz at gmail dot com 2014-05-17 12:59 ` redi at gcc dot gnu.org 2014-05-17 13:02 ` redi at gcc dot gnu.org 2014-05-17 13:09 ` redi at gcc dot gnu.org 2014-06-03 18:00 ` redi at gcc dot gnu.org 2014-06-03 18:01 ` redi at gcc dot gnu.org 2015-01-09 14:41 ` redi at gcc dot gnu.org 2015-01-09 14:41 ` redi at gcc dot gnu.org
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