Re: [PATCH] Fix libstdc++/9523 (and more)

[Benjamin Kosnik <bkoz at redhat dot com>]

>This patch fixes libstdc++/9523 and a few other related problems in ios_base.

I don't think 9523 is a bug, per se. The other issues you raise, which
are not filed in GNATS, actually are much more important.

I'll let the 9523 test case stand, because I think it's useful to track
what the implementation does in undefined cases like this.

>The standard streams (cin, cout, cerr, clog, wcin, wcout, wcerr, wclog) are
>now only constructed once when the first object of type ios_base::Init is
>constructed and are never destroyed, as required by 27.3 p2 and 27.4.2.1.6
>p3.

Yes, thanks for fixing this. I'm going to add test cases for this if I
can figure it out. I guess I can just do an address check to mark this.

>When the last ios_base::Init object is destroyed the standard output streams
>(cout, cerr, clog, wcout, wcerr, wclog) are now flushed, as required by
>27.4.2.1.6 p4. This in effect reverts the fix for libstdc++/5268, but it
>appears that this is the required behavior and that the test case for 5268
>has undefined behavior.

Yes. Thanks for this.

I made some changes and additions, but this is mostly in.

thanks!
benjamin

>2003-04-26  Petur Runolfsson  <peturr02 at ru dot is>
>
>	PR libstdc++/9523
>	* include/bits/ios_base.h (Init::_S_ios_create,
>	Init::_S_ios_destroy):  Remove declarations.
>	(Init::_S_ios_create_streams, Init::_S_ios_create_buffers,
>	Init::_S_ios_flush, Init::_S_ios_destroy_buffers):  Declare
>	* src/ios.cc (Init::_S_ios_create):  Remove
>	(Init::_S_ios_create_streams):  Create streams with NULL buffers.
>	(Init::_S_ios_create_buffers):  Create buffers and add to streams.
>	(Init::_S_ios_flush):  Flush standard output streams.
>	(Init::_S_ios_destroy):  Rename to...
>	(Init::_S_ios_destroy_buffers):  this.
>	(Init::Init):  Only construct streams once.
>	(Init::~Init):  Flush streams, don't destroy them.
>	(ios_base::sync_with_stdio):  Don't destroy streams, only buffers.
>	* testsuite/27_io/ios_base/sync_with_stdio/9523.cc:  New test.
>	* testsuite/27_io/objects/char/5.cc:  New test.
>	* testsuite/27_io/objects/char/5268.cc:  Avoid undefined behavior.
>	* testsuite/27_io/objects/char/6.cc:  New test.
>	* testsuite/27_io/objects/char/7.cc:  New test.