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From: Terry Lambert <terry@lambert.org>
Message-Id: <199601312047.NAA10480@phaeton.artisoft.com>
Subject: Re: signal masks and select
To: paul@sfe.com.au (Paul Hatchman)
Date: Wed, 31 Jan 1996 13:47:05 -0700 (MST)
Cc: leisner@sdsp.mc.xerox.com, linux-kernel@vger.rutgers.edu,
        hackers@FreeBSD.ORG
In-Reply-To: <199601310749.AA28625@rex.sfe.com.au> from "Paul Hatchman" at Jan 31, 96 06:49:00 pm
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> 
> This can be "solved" by using setjmp/longjmp with select.
> ie 
> 	if (setjmp (env, 1) == 0)
> 	{
> 		set_sigmask(unblock desired signals)
> 		select(...)
> 	}
> 
> and your signal handler does a longjmp (env)
> 
> There are drawbacks to this.. If you want to unblock signals outside of the 
> select, you must keep extra state information around, so that the signal handler
> knows whether to do a normal return or a longjmp.
> 
> May not be elegant, but it is surely better than using non portable methods.
> Actually is this truely portable? Will all unicies support longjmp from a 
> signal handler?

sigaction should be portable to all POSIX platforms.

siginterrupt should be portable to all BSD platforms starting with 4.2
Ultrix.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.