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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.lang.c
Subject: Re: Re: What is the setjump call
Message-ID: <4461@utzoo.UUCP>
Date: Mon, 15-Oct-84 12:58:18 EDT
Article-I.D.: utzoo.4461
Posted: Mon Oct 15 12:58:18 1984
Date-Received: Mon, 15-Oct-84 12:58:18 EDT
References: <2528@ihldt.UUCP> <169@rlgvax.UUCP>, <869@hou3c.UUCP>
Organization: U of Toronto Zoology
Lines: 13

> Actually, the fact that longjmp works with one argument is not an
> accident.  The SVR2 manual page for setjmp states, "If longjmp is
> invoked with a second argument of 0, setjmp will return 1."  This
> was done to make the two argument version of setjmp backward com-
> patable with the one argument version.

It's still an accident.  Calling a function (e.g. longjmp) with fewer
parameters than expected is **NOT** guaranteed to make the missing
parameters look like zeros.  This may work on some machines, but it
is not portable.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry