http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36231
--- Comment #17 from Ralf Wildenhues <rwild at gcc dot gnu.org> 2011-04-20 23:10:26 UTC --- (In reply to comment #13) > The last time I checked, the problem boiled down to: > > typedef __gthread_mutex_t __c_lock; > > in c_io_stdio.h, which we cannot remove right away for ABI reasons, because we > have a __c_lock data member in iostream classes. Of course the member is > normally completely unused these days, thus a possible ABI-safe way to attack > the problem would be replacing the data member with a dummy member of the same > size and alignment, the equivalent of: [...] > In order to figure out those quantities, ie, sizeof(__gthread_mutex_t) and > __alignof__(__gthread_mutex_t) we could probably use something like > [GLIBCXX_COMPUTE_STDIO_INTEGER_CONSTANTS], Ralf, people, what do you think? It is possible to compute size and alignment of types using Autoconf tests (even when cross-compiling), yes, with AC_CHECK_SIZEOF and AC_CHECK_ALIGNOF. But you are in a much better position to decide whether that is really sufficient here to solve all pending issues why the headers are dragged in. Thanks.
