Newsgroups: comp.lang.c
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: detecting invalid pointers
Message-ID: <1989Mar15.164554.21337@utzoo.uucp>
Organization: U of Toronto Zoology
References: <15495@cup.portal.com> <11998@haddock.ima.isc.com> <767@twwells.uucp> <24230@watmath.waterloo.edu>
Date: Wed, 15 Mar 89 16:45:54 GMT

In article <24230@watmath.waterloo.edu> rbutterworth@watmath.waterloo.edu (Ray Butterworth) writes:
>...There is a common case where the pointers are perfectly valid
>and yet you still need to check to see if one points inside the
>other even though they might actually point to completely different
>objects.
>Consider implementing memmov(void *to, void *from, size_t bytes).
>...
>As has been discussed in recent postings, there isn't any obvious
>simple way of performing these tests required by the pANS C library.

Nobody has ever pretended that it is possible to implement ANSI C in a
totally machine-independent way; there has to be hardware-specific code
down there somewhere.  The insides of things like memmove are likely
to be heavily machine-dependent in any case.
-- 
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