Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!hsi!stpstn!lerman
From: lerman@stpstn.UUCP (Ken Lerman)
Newsgroups: comp.lang.c
Subject: Re: Life after free?
Keywords: free malloc
Message-ID: <5620@stpstn.UUCP>
Date: 28 Sep 90 12:00:52 GMT
References: <quan.654410256@sol>
Reply-To: lerman@stpstn.UUCP (Ken Lerman)
Distribution: comp
Organization: The Stepstone Corporation, Sandy Hook, CT 06482
Lines: 32

In article <quan.654410256@sol> quan@sol.surv.utas.oz (Stephen Quan) writes:
->char *funny(ch)
->char ch;
->{
->  char *tmp;
->  int i;
->  
->  tmp = (char *) malloc(100);
->  for (i=0; i<=99 ; i++) *(tmp+i) = ch;
->  free(tmp);
->  return tmp;
->}
->
->Any comments on free-ing tmp before it is return-ed?
->
->Stephen Quan (quan@sol.surv.utas.edu.au)
->University of Tasmania.


Not only is it sensible, the semantics of free require it.  The item
freed is guaranteed to be valid until the next call to malloc,
realloc, ...

The intended use of funny() might be to format some characters which
will be printed by the user immediately after calling funny.
Unfortunately, the user can't call printf because printf might call
malloc which would destroy his temporary buffer.

So, yeah, it could be used.  Is it useful (in the sense of full of
use)? No way.

Ken