memcpy

[Larry Jones]

In article <1990Sep19.021418.11574 at maths.tcd.ie>, tim at maths.tcd.ie (Timothy Murphy) writes:
> Recently, while debugging the Unix version of unzip.c,
> I found a surprising discrepancy between 'memcpy' on various machines.
> 
> In unzip.c it is assumed that the effect of
> 	buf[0] = c;
> 	memcpy(buf+1, buf, 20);
> is to set
> 	buf[0] = buf[1] = buf[2] = ... = buf[21] = c.

This is a bug in unzip which is why almost every system required using
the version of memcpy that came with unzip instead of the one in the
standard library.  It has been fixed.  Note that unzip is inusual in
that it wants the DESCTRUCTIVE effect when the areas overlap where most
code wants the NON-DESCTRUCTIVE effect.
----
Larry Jones                         UUCP: uunet!sdrc!thor!scjones
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