Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!virtech!cpcahil
From: cpcahil@virtech.uucp (Conor P. Cahill)
Newsgroups: comp.lang.c
Subject: Re: Malloc in Turbo C
Keywords: Turbo C Malloc
Message-ID: <1990Feb28.024306.8801@virtech.uucp>
Date: 28 Feb 90 02:43:06 GMT
References: <26316@qfagus.OZ>
Reply-To: cpcahil@virtech.UUCP (Conor P. Cahill)
Organization: Virtual Technologies Inc., Sterling VA
Lines: 22

In article <26316@qfagus.OZ> gordon@qfagus.OZ (Peter Gordon) writes:
>X	head = (char **)malloc(200 * sizeof(char **));
>X	for(cp = head, i = 0; i < 200; ++i, ++cp)
>X	{
>X		fprintf(stdout,"Freeing %d\n", i);
>X		fflush(stdout);
>X		free(cp);
>X	}

The problem is that you can only call free with a pointer that is 
returned by malloc.  In this code the only valid call to free 
is free(head) or free(cp) for the first loop.

Due to a small amount of malloc chain info, most of your calls to free
are ignored, but you hit just the right circumstances to cause a problem
once in a while.

-- 
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| Conor P. Cahill     uunet!virtech!cpcahil      	703-430-9247	!
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