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From: edw@ius2.cs.cmu.edu (Eddie Wyatt)
Newsgroups: comp.lang.c
Subject: Re: Micro Soft C v.4.0 allocation problem
Message-ID: <1145@ius2.cs.cmu.edu>
Date: Wed, 6-May-87 09:57:22 EDT
Article-I.D.: ius2.1145
Posted: Wed May  6 09:57:22 1987
Date-Received: Sat, 9-May-87 00:40:41 EDT
References: <1051@mit-amt.MEDIA.MIT.EDU>
Distribution: world
Organization: Carnegie-Mellon University, CS/RI
Lines: 34
Keywords: alloc, calloc


  Just write a simple test program  like the following:

	extern char *calloc();

	main()
	    {
	    while (calloc((unsigned) 10) != NULL);
 	    printf("Returned NULL\n");
	    }

  You may want to check the addresses returned by calloc to may sure
that they are all ascending or dsecending order.  If they are not then
this might, but not necessarily, indicate something is wrong with
calloc.

  Since you are using calloc in a large system, there are many ways 
in which memory heap can get corrupted.  Things I have run up against
are:

	1. accessing memory that was freed

	2. over indexing arrays

	3. not allocating enough memory for what I am storing

  SUN systems provide a debugging package for the memory allocation routines
malloc_debug(level) and malloc_verify() in /usr/lib/debug/malloc.o.  I don't
know if your system does but I have these VERY useful.

-- 
					Eddie Wyatt

e-mail: edw@ius2.cs.cmu.edu