Path: utzoo!attcan!uunet!wuarchive!cs.utexas.edu!sun-barr!lll-winken!unixhub!shelby!neon!Gang-of-Four!dkeisen
From: dkeisen@Gang-of-Four.Stanford.EDU (Dave Eisen)
Newsgroups: comp.lang.c
Subject: Re: why is free() a void?
Message-ID: <1990Oct24.211905.225@Neon.Stanford.EDU>
Date: 24 Oct 90 21:19:05 GMT
References: <1749@meaddata.meaddata.com>
Sender: news@Neon.Stanford.EDU (USENET News System)
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Lines: 28

In article <1749@meaddata.meaddata.com> rob@pmserv.meaddata.com writes:
>
>As the subject says, I'm curious as to why free() does not return a value.
>
>    "void free(void *p)
>        ... p MUST be a pointer to space previously allocated by calloc,
>        malloc, or realloc."   (Emphasis on MUST by me.)
>
>What happens if p WASN'T allocated as it should've been??  How do we know
>there was a problem??  Is there really a problem??
>

There most certainly is a problem, free can do all kinds of damage if it
is passed a pointer to (for instance) static memory. Most frees don't check
if the address they are passed makes sense for a free call, most frees
have no way of doing this even if they wanted to. So it is up to the
programmer to be sure that the memory to be freed was obtained from
malloc or its cousins.





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