------- Comment #5 from pcarlini at suse dot de 2007-03-12 18:51 ------- (In reply to comment #4) > Perhaps there are different degrees of thread safety here. > > If I write my multi-threaded program such that only one thread does stream I/O > with libstdc++, I would expect it to operate safely with respect to the locale > issue. But it will not: any other thread which modifies errno (via set_errno) > is potential trouble for my stream I/O thread.
That's not correct. Anyone, anywhere, irrespective of I/O can do a "setlocale" and that will change the global locale, which is also changed in a thread-unsafe way at any I/O. Anyway, what happens in the GNU systems is that errno is a per-thread variable and the __convert_to_v code has to do nothing special, just safely use it. In the systems using the generic locale model a completely different strategy is needed if the C library of those systems doesn't provide a thread-safe implementation. I have no idea what that can be and in any case must be solved together with the setlocale one. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31117
