Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!rice!sun-spots-request
From: wilde@cbnewsd.att.com (charles.j.wilde)
Newsgroups: comp.sys.sun
Subject: semaphores interacting with lockscreen(1)
Keywords: Miscellaneous
Message-ID: <6589@brazos.Rice.edu>
Date: 11 Apr 90 22:24:42 GMT
Sender: root@rice.edu
Organization: Sun-Spots
Lines: 14
Approved: Sun-Spots@rice.edu
X-Sun-Spots-Digest: Volume 9, Issue 118, message 6

I've run into a problem with interaction between lockscreen(1) and
semaphores.  I've got a program running which attempts to decrement a
semaphore, and then waits for some other process to increment it.  If I
enter lockscreen at this point, when I come back and remove lockscreen,
the process waiting on the semaphore exits with an error, "system call
interrupted."  Apparently, the signal from lockscreen causes semop() to
fail due to EINTR, a signal interrupting the call.  Should signals from
lockscreen be interacting with user application semaphores?  Am I supposed
to handle signals like INT by ignoring them with signal(SIGINT, SIG_IGN)?
Any help on this matter would be appreciated.  This program is run on a
Sun 3 with OS 4.0.3.

Chuck Wilde
ihlpe!cjw