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From: Tim Rentsch
Newsgroups: comp.arch
Subject: Re: Computer architects leaving Intel...
Date: Wed, 11 Sep 2024 09:29:04 -0700
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Josh Vanderhoof writes:
[how to write a portable, UB-free check if mempcy() intervals overlap]
> It is legal to test for equality between pointers to different objects
Right. This observation is the key insight.
> so you could test for overlap by testing against every element in the
> array.
For a complete test, compare the address of every element in both
arrays. For example:
#include
_Bool
memcpy_intervals_overlap( void *const vd, void *const vs, size_t n ){
char *d = vd, *s = vs;
size_t k = 0;
while( k < n && d != vs && s != vd ) k++, d++, s++;
return k < n;
}