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* [Bug c++/51379] New: reinterpret_cast is not particularly useful
@ 2011-12-01 12:57 piotr.wyderski at gmail dot com
2011-12-01 12:58 ` [Bug c++/51379] " piotr.wyderski at gmail dot com
` (6 more replies)
0 siblings, 7 replies; 8+ messages in thread
From: piotr.wyderski at gmail dot com @ 2011-12-01 12:57 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51379
Bug #: 51379
Summary: reinterpret_cast is not particularly useful
Classification: Unclassified
Product: gcc
Version: 4.6.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: piotr.wyderski@gmail.com
The following code:
int main() {
unsigned long t1 = 0;
unsigned long t2 = 1;
t1 = reinterpret_cast<unsigned long>(t2);
return 0;
}
compiled using GCC 4.6.2 on Linux/x64:
g++ test.cpp
fails displaying:
test.cpp:5:44: error: invalid cast from type 'long unsigned int' to type 'long
unsigned int'
IMHO this is a rather urgent issue.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/51379] reinterpret_cast is not particularly useful
2011-12-01 12:57 [Bug c++/51379] New: reinterpret_cast is not particularly useful piotr.wyderski at gmail dot com
@ 2011-12-01 12:58 ` piotr.wyderski at gmail dot com
2011-12-01 13:20 ` redi at gcc dot gnu.org
` (5 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: piotr.wyderski at gmail dot com @ 2011-12-01 12:58 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51379
--- Comment #1 from Piotr Wyderski <piotr.wyderski at gmail dot com> 2011-12-01 12:58:16 UTC ---
Both static_cast and C-type cast work as expected.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/51379] reinterpret_cast is not particularly useful
2011-12-01 12:57 [Bug c++/51379] New: reinterpret_cast is not particularly useful piotr.wyderski at gmail dot com
2011-12-01 12:58 ` [Bug c++/51379] " piotr.wyderski at gmail dot com
@ 2011-12-01 13:20 ` redi at gcc dot gnu.org
2011-12-01 13:59 ` jakub at gcc dot gnu.org
` (4 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: redi at gcc dot gnu.org @ 2011-12-01 13:20 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51379
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-12-01 13:20:16 UTC ---
This is required by the standard.
[expr.reinterpret.cast] explicitly lists all the conversion allowed by
reinterpret_cast
You'll get the same result from http://llvm.org/demo/ and
http://www.comeaucomputing.com/tryitout/
If GCC, EDG and Clang all reject your code then your code is probably wrong.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/51379] reinterpret_cast is not particularly useful
2011-12-01 12:57 [Bug c++/51379] New: reinterpret_cast is not particularly useful piotr.wyderski at gmail dot com
2011-12-01 12:58 ` [Bug c++/51379] " piotr.wyderski at gmail dot com
2011-12-01 13:20 ` redi at gcc dot gnu.org
@ 2011-12-01 13:59 ` jakub at gcc dot gnu.org
2011-12-01 14:07 ` redi at gcc dot gnu.org
` (3 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: jakub at gcc dot gnu.org @ 2011-12-01 13:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51379
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org,
| |jason at gcc dot gnu.org
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-12-01 13:58:29 UTC ---
I wonder about the C++11 wording though, in C++03 it said:
"The reinterpret_cast operator shall not cast away constness. [Note: see 5.2.11
for the definition of ‘‘casting away constness’’. Subject to the restrictions
in this section, an expression may be cast to its own type using a
reinterpret_cast operator. ]"
but in C++11:
"The reinterpret_cast operator shall not cast away constness (5.2.11). An
expression of integral, enumeration, pointer, or pointer-to-member type can be
explicitly converted to its own type; such a cast yields the
value of its operand."
For the latter wording it isn't obvious if the second sentence is subject to
the other restrictions or not.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/51379] reinterpret_cast is not particularly useful
2011-12-01 12:57 [Bug c++/51379] New: reinterpret_cast is not particularly useful piotr.wyderski at gmail dot com
` (2 preceding siblings ...)
2011-12-01 13:59 ` jakub at gcc dot gnu.org
@ 2011-12-01 14:07 ` redi at gcc dot gnu.org
2011-12-31 21:54 ` [Bug c++/51379] [C++0x] [DR 799] " paolo.carlini at oracle dot com
` (2 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: redi at gcc dot gnu.org @ 2011-12-01 14:07 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51379
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |NEW
Last reconfirmed| |2011-12-01
Resolution|INVALID |
Ever Confirmed|0 |1
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-12-01 14:06:47 UTC ---
Ah good point, I didn't realise DR 799 changed that
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#799
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/51379] [C++0x] [DR 799] reinterpret_cast is not particularly useful
2011-12-01 12:57 [Bug c++/51379] New: reinterpret_cast is not particularly useful piotr.wyderski at gmail dot com
` (3 preceding siblings ...)
2011-12-01 14:07 ` redi at gcc dot gnu.org
@ 2011-12-31 21:54 ` paolo.carlini at oracle dot com
2012-01-01 20:22 ` paolo at gcc dot gnu.org
2012-01-01 20:24 ` paolo.carlini at oracle dot com
6 siblings, 0 replies; 8+ messages in thread
From: paolo.carlini at oracle dot com @ 2011-12-31 21:54 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51379
Paolo Carlini <paolo.carlini at oracle dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
AssignedTo|unassigned at gcc dot |paolo.carlini at oracle dot
|gnu.org |com
--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-12-31 17:58:09 UTC ---
On it.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/51379] [C++0x] [DR 799] reinterpret_cast is not particularly useful
2011-12-01 12:57 [Bug c++/51379] New: reinterpret_cast is not particularly useful piotr.wyderski at gmail dot com
` (4 preceding siblings ...)
2011-12-31 21:54 ` [Bug c++/51379] [C++0x] [DR 799] " paolo.carlini at oracle dot com
@ 2012-01-01 20:22 ` paolo at gcc dot gnu.org
2012-01-01 20:24 ` paolo.carlini at oracle dot com
6 siblings, 0 replies; 8+ messages in thread
From: paolo at gcc dot gnu.org @ 2012-01-01 20:22 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51379
--- Comment #6 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2012-01-01 20:21:39 UTC ---
Author: paolo
Date: Sun Jan 1 20:21:36 2012
New Revision: 182775
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=182775
Log:
/cp
2012-01-01 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/51379
* typeck.c (build_reinterpret_cast_1): Implement resolution of
DR 799.
/testsuite
2012-01-01 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/51379
* g++.dg/conversion/reinterpret4.C: New.
* g++.dg/conversion/reinterpret1.C: Adjust.
Added:
trunk/gcc/testsuite/g++.dg/conversion/reinterpret4.C
Modified:
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/typeck.c
trunk/gcc/testsuite/ChangeLog
trunk/gcc/testsuite/g++.dg/conversion/reinterpret1.C
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/51379] [C++0x] [DR 799] reinterpret_cast is not particularly useful
2011-12-01 12:57 [Bug c++/51379] New: reinterpret_cast is not particularly useful piotr.wyderski at gmail dot com
` (5 preceding siblings ...)
2012-01-01 20:22 ` paolo at gcc dot gnu.org
@ 2012-01-01 20:24 ` paolo.carlini at oracle dot com
6 siblings, 0 replies; 8+ messages in thread
From: paolo.carlini at oracle dot com @ 2012-01-01 20:24 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51379
Paolo Carlini <paolo.carlini at oracle dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.7.0
--- Comment #7 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-01-01 20:23:50 UTC ---
Done.
^ permalink raw reply [flat|nested] 8+ messages in thread
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2011-12-01 12:57 [Bug c++/51379] New: reinterpret_cast is not particularly useful piotr.wyderski at gmail dot com
2011-12-01 12:58 ` [Bug c++/51379] " piotr.wyderski at gmail dot com
2011-12-01 13:20 ` redi at gcc dot gnu.org
2011-12-01 13:59 ` jakub at gcc dot gnu.org
2011-12-01 14:07 ` redi at gcc dot gnu.org
2011-12-31 21:54 ` [Bug c++/51379] [C++0x] [DR 799] " paolo.carlini at oracle dot com
2012-01-01 20:22 ` paolo at gcc dot gnu.org
2012-01-01 20:24 ` paolo.carlini at oracle dot com
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