Path: utzoo!attcan!uunet!samsung!uakari.primate.wisc.edu!sdd.hp.com!ucsd!ucbvax!gmr.COM!JORDAN
From: JORDAN@gmr.COM
Newsgroups: comp.sys.sgi
Subject: Does UNIX/IRIX use SIGALRM
Message-ID: <9008201401.aa27534@VGR.BRL.MIL>
Date: 20 Aug 90 17:32:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 29

Fellow netters:

I was using the setitimer(ITIMER_REAL, &itime, &oitime) command to
signal the interrupt SIGALRM.

Alarming results...

I set itime.it_value.tv_usec = 30000 (or 30 msec); result, 33 hz (okay)
I set itime.it_value.tv_usec = 20000 ; result, 33 hz (WHOOPS!) 
should be 50 hz.

I ran this with graphics, but I jumped around all the graphics routines in
the loop.

The Question...

Is something else out there setting the SIGALRM such as UNIX or IRIX OR
swapinterval()?

Meanwhile...

I have hacked a fix using times() where I simply check the time at the
end of the loop.

ted p mugabi-jordan
gm systems engr ctr
1151 crooks road
troy, michigan 48084
313 280 6766