[Bug c++/46600] New: Default move constructor copies array elements instead of moving them.

[Bug c++/46600] New: Default move constructor copies array elements instead of moving them.

[yacwroy at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46600

           Summary: Default move constructor copies array elements instead
                    of moving them.
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: yacwroy@gmail.com


Created attachment 22482
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22482
Complete example code. Compile with 4.6 or higher using -std=c++0x.

N3126: § 12.8.17 [move constructors]:
--(3): "an array is initialized by moving each element in the manner
appropriate to the element type"

If you have a class with a member array and you call the default move
constructor for said class, the move constructor COPIES said array elements.
From what the standard says, it seems it should MOVE these elements.



VERSION: 4.6.0 20100529 (experimental) (GCC)
4.5.1 is unable to explicitly default the move constructor.
I don't have any other functional versions between these two.
NOTE: I have added Pedro Lamarão's patch
http://gcc.gnu.org/ml/gcc-patches/2007-04/msg00620.html to my 4.6.0 but I can't
see this affecting anything.

TARGET: x86_64-unknown-linux-gnu
SYSTEM: Core2Duo / Ubuntu(64) 10.4.

ATTACHMENT:
Compiles OK with -std=c++0x.
OUTPUT:
copy
copy
move
PROBLEM:
According to the C++ spec (ver N3126), I think the first 2 "copy"s should be
"move"s.

[Bug c++/46600] Default move constructor copies array elements instead of moving them.

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46600

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2010-11-22 12:54:04 UTC ---
dup of PR 46103 which was fixed last month 

if you want to test the latest development version you shouldn't use a build
from 6 months ago

*** This bug has been marked as a duplicate of bug 46103 ***

[Bug c++/46600] Default move constructor copies array elements instead of moving them.

[yacwroy at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46600

--- Comment #2 from Simon Hill <yacwroy at gmail dot com> 2010-11-22 23:21:04 UTC ---
Sorry about that.
All that work and I didn't even notice my test GCC was the wrong one.

[Bug c++/46600] Default move constructor copies array elements instead of moving them.

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46600

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2010-11-22 23:48:47 UTC ---
you should definitely try a recent snapshot, there's been a lot of work on move
support and g++ is pretty close to the n3126 definitions (although those aren't
set in stone yet and might change)