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From: boykin@custom.UUCP (Joseph Boykin)
Newsgroups: comp.unix.wizards
Subject: Re: Why doesn't this qsort example work?
Message-ID: <770@custom.UUCP>
Date: Tue, 20-Oct-87 13:24:25 EDT
Article-I.D.: custom.770
Posted: Tue Oct 20 13:24:25 1987
Date-Received: Thu, 22-Oct-87 05:46:02 EDT
References: <7527@g.ms.uky.edu>
Organization: Custom Software Systems; Natick, MA
Lines: 24
Summary: Wrong parameter to qsort

In article <7527@g.ms.uky.edu>, sean@ms.uky.edu (Sean Casey) writes:
> 
> I'm trying to use qsort(3) for the first time and I'm having a bit of
> trouble.

...Bunch of stuff deleted...

> 	qsort(&t[0], 2, sizeof(struct tstr), (*compar)());

The fourth (last) argument to qsort is the address of the function
which will do the comparison.  What you've done here is to *call*
the function 'compar' without any arguments and the return value
of that function call would be passed to qsort.  The function isn't
core dumping because of bogus values of 'a' as you stated, but
because the pointers 'x' and 'y' within the function were using
whatever garbage values were left over on the stack.  The correct
call to qsort would be:

 	qsort(&t[0], 2, sizeof(struct tstr), compar);
-- 

Joe Boykin
Custom Software Systems
...necntc!custom!boykin