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From: alan@ukpoit.co.uk (Alan Barclay)
Newsgroups: comp.unix.questions
Subject: Re: What was the signal?
Message-ID: <1991Mar20.114107.2078@ukpoit.co.uk>
Date: 20 Mar 91 11:41:07 GMT
References: <1991Mar20.113657.1959@ukpoit.co.uk>
Organization: iT - The Information Technology Business Of The Post Office
Lines: 11

In article <1991Mar20.113657.1959@ukpoit.co.uk> howard@ukpoit.co.uk (Howard the Hacker) writes:
>
>I have a C program doing a msgrcv(2) which may be interrupted by a SIGALRM. This
>is processed by a handler function. On return a failure of msgrcv is found
>and found to be due to an interrupt. The question is, will any ignored signal
>(ignored by default) also interrupt the msgrcv, and if so is it possible to find
>out what the actual signal was? If the signal was not SIGALRM, the msgrcv should
>not be tried again, but how can I tell?

catch SIGALRM, using signal(2), set a flag in the signal catching routine,
and check for the flag being set.