Re: More info on sporadic OS/X crash

[YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>]

>>>>> On Sun, 25 Apr 2004 10:49:07 -0700, Steven Tamm <steventamm@mac.com> said:

> The patch seemed to make sense to be, except for the FD_CLR
> (i.e. the bug in select from 10.1) I forgot to ask, have you tried
> that patch on 10.2 or just 10.3?

I just tried the patch on both 10.1.5 and 10.2.8, but I could not find
any problems by a few tests on subprocesses.  If you have a specific
example, maybe I can test it.

> And with the non-carbon build?

For the X11 build, fd 0 is excluded from input_wait_mask with
add_keyboard_wait_descriptor in x_term_init.  For the Carbon build, fd
0 is never consulted in sys_select (in mac.c with the patch), but the
window event queue is consulted instead.

A comment in mac.c says:

   When Emacs is started from the Finder, SELECT always immediately
   returns as if input is present when file descriptor 0 is polled for
   input.  Strangely, when Emacs is run as a GUI application from the
   command line, it blocks in the same situation.  This `wrapper' of
   the system call SELECT corrects this discrepancy.

According to the output of lsof, fd 0 is bound to /dev/null for the
former case, whereas it is bound to the tty from which Emacs is
invoked for the latter case.  That would explain the above phenomena.

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp