Bug 56011 - [C++11] std::atomic<bool> and std::atomic_bool miss volatile assignment operator overload
Summary: [C++11] std::atomic<bool> and std::atomic_bool miss volatile assignment opera...
Status: RESOLVED FIXED
Alias: None
Product: gcc
Classification: Unclassified
Component: libstdc++ (show other bugs)
Version: 4.8.0
: P3 normal
Target Milestone: 4.7.3
Assignee: Not yet assigned to anyone
URL:
Keywords: rejects-valid
Depends on:
Blocks:
 
Reported: 2013-01-16 20:47 UTC by Daniel Krügler
Modified: 2013-02-27 00:58 UTC (History)
0 users

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Known to fail:
Last reconfirmed: 2013-01-16 00:00:00

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Description Daniel Krügler 2013-01-16 20:47:14 UTC 
Using gcc 4.8.0 trunk the following program - compiled with the flags

-pedantic-errors -std=c++11 -Wall

is rejected:

//----------------------------------
#include <atomic>

int main() {
  volatile std::atomic<bool> ab1;
  ab1 = true;
  volatile std::atomic_bool ab2;
  ab2 = true;
}
//----------------------------------

"main.cpp||In function 'int main()':|
main.cpp|5|error: ambiguous overload for 'operator=' (operand types are 'volatile std::atomic<bool>' and 'bool')|
main.cpp|5|note: candidates are:|
[..]gcc\include\c++\4.8.0\atomic|485|note: std::atomic<bool>& std::atomic<bool>::operator=(const std::atomic<bool>&) volatile <deleted>|
[..]gcc\include\c++\4.8.0\atomic|64|note: std::atomic_bool& std::atomic_bool::operator=(const std::atomic_bool&) volatile <deleted>|
main.cpp|7|error: use of deleted function 'std::atomic_bool& std::atomic_bool::operator=(const std::atomic_bool&) volatile'|
[..]gcc\include\c++\4.8.0\atomic|64|error: declared here|
"

The problem is due to the missing overload (part of the specification):

bool operator=(bool __i) volatile noexcept;
Comment 1 Jonathan Wakely 2013-02-26 23:46:31 UTC 
Author: redi
Date: Tue Feb 26 23:46:21 2013
New Revision: 196296

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=196296
Log:
	PR libstdc++/56012
	* include/bits/atomic_base.h (atomic_flag): Fix narrowing conversion.
	* testsuite/29_atomics/atomic/operators/56012.cc: New.

	PR libstdc++/56011
	* include/std/atomic (atomic<bool>::operator=(bool) volatile): Add
	missing overload.
	* testsuite/29_atomics/atomic/operators/56011.cc: New.

Added:
    trunk/libstdc++-v3/testsuite/29_atomics/atomic/operators/56011.cc
    trunk/libstdc++-v3/testsuite/29_atomics/atomic_flag/cons/56012.cc
Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/bits/atomic_base.h
    trunk/libstdc++-v3/include/std/atomic
Comment 2 Jonathan Wakely 2013-02-27 00:57:45 UTC 
Author: redi
Date: Wed Feb 27 00:57:36 2013
New Revision: 196301

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=196301
Log:
	PR libstdc++/56012
	* include/bits/atomic_base.h (atomic_flag): Fix narrowing conversion.
	* testsuite/29_atomics/atomic/operators/56012.cc: New.

	PR libstdc++/56011
	* include/std/atomic (atomic<bool>::operator=(bool) volatile): Add
	missing overload.
	* testsuite/29_atomics/atomic/operators/56011.cc: New.

Added:
    branches/gcc-4_7-branch/libstdc++-v3/testsuite/29_atomics/atomic/operators/56011.cc
    branches/gcc-4_7-branch/libstdc++-v3/testsuite/29_atomics/atomic_flag/cons/56012.cc
Modified:
    branches/gcc-4_7-branch/libstdc++-v3/ChangeLog
    branches/gcc-4_7-branch/libstdc++-v3/include/bits/atomic_base.h
    branches/gcc-4_7-branch/libstdc++-v3/include/std/atomic
Comment 3 Jonathan Wakely 2013-02-27 00:58:28 UTC 
fixed