Re: Mac OS X - Hang / C-g problem patch

[Steven Tamm <steventamm@mac.com>]

Hi Andrew (and others interested in this problem),

I've checked in your patch with a few modification.
First, I added code to check for C-g instead of C-. to macterm.c.  
Right now it will only work if the quit_char is C-g, but I plan on 
adding code that will convert from ascii -> keycode later.  Anywhere 
this check should be done, call mac_check_for_quit_char().
Second, I made sys_read depend on sys_select to do the blocking.  I 
also made sys_select handle NULL as the timeout (so that sys_read could 
block forever)
Third, I didn't use signals, but instead sent the quit_char as an 
input_event to kbd_buffer_store_event.  This seemed like a better idea 
than directly using signals because things like last_event_timestamp 
are updated.
I left the call to mac_check_for_quit_char in Feval with a note in the 
cvs log that it might be removed.

I tried to run some profiling tests but none of the data I got seemed 
useful.  It seems to not be that expensive a call.  In any case I filed 
a couple radar bugs to see if the WindowManager could be programmed to 
send a signal based on a hotkey.  It's bug 3121160  (Allow ability to 
have a keypress cause a signal in Carbon).  I also reported a bug to be 
able to set the main event queue for an application to be a secondary 
thread, but doubt that it will go anywhere due to thread safety issues.

-Steven