Re: [Boost-bugs] [Boost C++ Libraries] #10125: call_once: compile errors in variadic version with rvalue reference emulation

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #10125: call_once: compile errors in variadic version with rvalue reference emulation
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-06-29 21:45:57

#10125: call_once: compile errors in variadic version with rvalue reference
emulation
-------------------------------+----------------------
  Reporter:  raad@…            |      Owner:  viboes
      Type:  Bugs              |     Status:  assigned
 Milestone:  To Be Determined  |  Component:  thread
   Version:  Boost 1.55.0      |   Severity:  Problem
Resolution:                    |   Keywords:
-------------------------------+----------------------

Comment (by viboes):

 I have found this comment


 {{{
 // For C++11 call_once interface the compiler MUST support constexpr.
 // Otherwise once_flag would be initialized during dynamic initialization
 stage, which is not thread-safe.
 #if defined(BOOST_THREAD_PROVIDES_ONCE_CXX11)
 #if defined(BOOST_NO_CXX11_CONSTEXPR)
 #undef BOOST_THREAD_PROVIDES_ONCE_CXX11
 #endif
 #endif
 }}}


 And


 {{{
 #if BOOST_THREAD_VERSION>=3

 // ONCE_CXX11
 // fixme BOOST_THREAD_PROVIDES_ONCE_CXX11 doesn't works when thread.cpp is
 compiled BOOST_THREAD_VERSION 3
 #if ! defined BOOST_THREAD_DONT_PROVIDE_ONCE_CXX11 \
  && ! defined BOOST_THREAD_PROVIDES_ONCE_CXX11
 #define BOOST_THREAD_DONT_PROVIDE_ONCE_CXX11
 #endif
 }}}


 I will comeback with more insight.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10125#comment:4>
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