memcpy vs. memmove (was: Re: Explanation, please!)

[Doug Gwyn]

In article <7039 at bloom-beacon.MIT.EDU> scs at adam.pika.mit.edu (Steve Summit) writes:
>I'll probably be disgusted by the answer, but can someone explain
>why two functions are needed instead of one?  Why not just add
>the guarantee to memcpy?

(1) many people want a fast block-move, many want one that does the
"correct" thing on overlaps.  Two routines allows the application to
choose the trade-off.  A vendor could choose to make memcpy just
another entry point for memmove.

(2) it's possible that some existing (nonportable) applications depend
on the specific implementation of their current memcpy().