Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!usc!srhqla!quad1!ttidca!mb
From: mb@ttidca.TTI.COM (Michael Bloom)
Newsgroups: comp.unix.wizards
Subject: Re: driver close from exit can't catch signal?
Message-ID: <18901@ttidca.TTI.COM>
Date: 31 Jul 90 04:24:21 GMT
References: <26789@nuchat.UUCP>
Reply-To: mb@ttidca.tti.com (Michael Bloom)
Organization: Citicorp/TTI, Santa Monica
Lines: 17

In article <26789@nuchat.UUCP> steve@nuchat.UUCP (Steve Nuchia) writes:

>Since the interupt wasn't guaranteed to come, I wanted to
>be able to catch a signal.  I found that it works when the
>user calls close directly but not when close is called from exit.

>This is in a SysV thing.  Is this normal and expected?  I couldn't
>find anything about it in the AT+T driver books.

Yes. If you run /etc/crash while your driver is blocked in a close
called from exit, you'll see that all signals have been set to
SIG_IGN.

I dealt with a problem somewhat like yours once with a test of the
form "(u.u_signal[SIGKILL -1] == SIG_IGN)", which should only be true
in your close routine if it is called from exit. I didn't really like
it, but it did the job.