Jean-Paul Calderone <[EMAIL PROTECTED]> wrote: > On Mon, 04 Sep 2006 17:24:56 +0100, > David Hopwood <[EMAIL PROTECTED] > der.co.uk> wrote: > >Jean-Paul Calderone wrote: > >> PyGTK would presumably implement its pending call callback by writing a > >> byte to a pipe which it is also passing to poll(). > > > >But doing that in a signal handler context invokes undefined behaviour > >according to POSIX. > > write(2) is explicitly listed as async-signal safe in IEEE Std 1003.1, 2004. > Was this changed in a later edition? Otherwise, I don't understand what you > mean by this.
Try looking at the C90 or C99 standard, for a start :-( NOTHING may safely be done in a real signal handler, except possibly setting a value of type static volatile sig_atomic_t. And even that can be problematic. And note that POSIX defers to C on what the C languages defines. So, even if the function is async-signal-safe, the code that calls it can't be! POSIX's lists are complete fantasy, anyway. Look at the one that defines thread-safety, and then try to get your mind around what exit being thread-safe actually implies (especially with regard to atexit functions). Regards, Nick Maclaren, University of Cambridge Computing Service, New Museums Site, Pembroke Street, Cambridge CB2 3QH, England. Email: [EMAIL PROTECTED] Tel.: +44 1223 334761 Fax: +44 1223 334679 _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
