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* [Bug libstdc++/53429] New: complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11
@ 2012-05-21 4:03 jyasskin at gcc dot gnu.org
2012-05-21 5:52 ` [Bug libstdc++/53429] " jyasskin at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: jyasskin at gcc dot gnu.org @ 2012-05-21 4:03 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53429
Bug #: 53429
Summary: complex::{imag,real} should be marked alwaysinline to
guarantee libstdc++ binary compatibility between C++98
and C++11
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: jyasskin@gcc.gnu.org
The non-const overloads of std::complex::real and std::complex::imag go from
returning _Tp& to _Tp in C++98 vs C++11:
http://gcc.gnu.org/viewcvs/trunk/libstdc%2B%2B-v3/include/std/complex?view=markup.
libstdc++ includes explicit instantiations of operator<< and operator>> with
complex arguments:
http://gcc.gnu.org/viewcvs/trunk/libstdc%2B%2B-v3/src/c%2B%2B98/complex_io.cc?view=markup.
These operator<< and operator>> overloads call complex::real() and
complex::imag(). If those calls are inlined (which is likely), so that no weak
definition of real() and imag() is exposed to users of the library, then I
believe all is well. However, if the compiler decides not to inline them, then
people linking libstdc++ from the other version of the language may wind up
with two conflicting weak definitions of the symbols.
I think marking them as alwaysinline would guarantee compatibility.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug libstdc++/53429] complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11
2012-05-21 4:03 [Bug libstdc++/53429] New: complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11 jyasskin at gcc dot gnu.org
@ 2012-05-21 5:52 ` jyasskin at gcc dot gnu.org
2012-05-21 10:16 ` rguenth at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: jyasskin at gcc dot gnu.org @ 2012-05-21 5:52 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53429
--- Comment #1 from Jeffrey Yasskin <jyasskin at gcc dot gnu.org> 2012-05-21 04:03:26 UTC ---
So far, this is purely a theoretical incompatibility. I haven't actually seen a
compiled libstdc++.so that exposes a version-specific complex::{imag,real}.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug libstdc++/53429] complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11
2012-05-21 4:03 [Bug libstdc++/53429] New: complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11 jyasskin at gcc dot gnu.org
2012-05-21 5:52 ` [Bug libstdc++/53429] " jyasskin at gcc dot gnu.org
@ 2012-05-21 10:16 ` rguenth at gcc dot gnu.org
2012-05-21 15:36 ` jyasskin at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-05-21 10:16 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53429
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-05-21 09:23:07 UTC ---
Note that C++98 and C++11 are not compatible anyway, for example due to the
changed way which classes are considered POD.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug libstdc++/53429] complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11
2012-05-21 4:03 [Bug libstdc++/53429] New: complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11 jyasskin at gcc dot gnu.org
2012-05-21 5:52 ` [Bug libstdc++/53429] " jyasskin at gcc dot gnu.org
2012-05-21 10:16 ` rguenth at gcc dot gnu.org
@ 2012-05-21 15:36 ` jyasskin at gcc dot gnu.org
2012-05-21 17:47 ` paolo.carlini at oracle dot com
2012-05-22 13:00 ` [Bug libstdc++/53429] libstdc++ should guarantee not to expose complex::{imag,real} so it supports both " jyasskin at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jyasskin at gcc dot gnu.org @ 2012-05-21 15:36 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53429
--- Comment #3 from Jeffrey Yasskin <jyasskin at gcc dot gnu.org> 2012-05-21 15:30:45 UTC ---
Richard, I'm not asking that it be possible to link together code compiled in
C++98 and C++11 mode. I'm asking that gcc be able to build in C++11 mode at
all. If libstdc++.so exposed the c++98 version of complex::real(), then all
C++11 programs that used complex would be potentially broken.
Another way to fix this would, of course, be to either expose a configuration
option to build libstdc++.so in C++11 mode or to install two different .so
files in parallel, but doing that seems unnecessarily hostile to users when it
would be pretty easy to guarantee that the one .so works for both versions of
the language.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug libstdc++/53429] complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11
2012-05-21 4:03 [Bug libstdc++/53429] New: complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11 jyasskin at gcc dot gnu.org
` (2 preceding siblings ...)
2012-05-21 15:36 ` jyasskin at gcc dot gnu.org
@ 2012-05-21 17:47 ` paolo.carlini at oracle dot com
2012-05-22 13:00 ` [Bug libstdc++/53429] libstdc++ should guarantee not to expose complex::{imag,real} so it supports both " jyasskin at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: paolo.carlini at oracle dot com @ 2012-05-21 17:47 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53429
--- Comment #4 from Paolo Carlini <paolo.carlini at oracle dot com> 2012-05-21 15:59:44 UTC ---
Before fiddling with always inline, I would rather add 3 overloads of
operator<< for float, double and long double, using __rep instead of real and
imag. But I don't have a strong opinion about the PR (I have it about not using
the attribute ;) if somebody wants to do something, please double check with
Gaby.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug libstdc++/53429] libstdc++ should guarantee not to expose complex::{imag,real} so it supports both C++98 and C++11
2012-05-21 4:03 [Bug libstdc++/53429] New: complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11 jyasskin at gcc dot gnu.org
` (3 preceding siblings ...)
2012-05-21 17:47 ` paolo.carlini at oracle dot com
@ 2012-05-22 13:00 ` jyasskin at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jyasskin at gcc dot gnu.org @ 2012-05-22 13:00 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53429
Jeffrey Yasskin <jyasskin at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |NEW
Last reconfirmed| |2012-05-22
CC| |gdr at gcc dot gnu.org
Resolution|INVALID |
Summary|complex::{imag,real} should |libstdc++ should guarantee
|be marked alwaysinline to |not to expose
|guarantee libstdc++ binary |complex::{imag,real} so it
|compatibility between C++98 |supports both C++98 and
|and C++11 |C++11
Ever Confirmed|0 |1
--- Comment #5 from Jeffrey Yasskin <jyasskin at gcc dot gnu.org> 2012-05-22 12:58:14 UTC ---
Specializing operator<< sounds fine too. Adding Gaby for his opinion, and
reopening since I'm not sure Richard understood the request.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-05-22 12:59 UTC | newest]
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2012-05-21 4:03 [Bug libstdc++/53429] New: complex::{imag,real} should be marked alwaysinline to guarantee libstdc++ binary compatibility between C++98 and C++11 jyasskin at gcc dot gnu.org
2012-05-21 5:52 ` [Bug libstdc++/53429] " jyasskin at gcc dot gnu.org
2012-05-21 10:16 ` rguenth at gcc dot gnu.org
2012-05-21 15:36 ` jyasskin at gcc dot gnu.org
2012-05-21 17:47 ` paolo.carlini at oracle dot com
2012-05-22 13:00 ` [Bug libstdc++/53429] libstdc++ should guarantee not to expose complex::{imag,real} so it supports both " jyasskin at gcc dot gnu.org
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