On Mon, Jan 13, 2014 at 04:44:22PM -0600, Lawrence K. Chen, P.Eng. wrote: > Hmmm, from what I vaguely recall from my software engineering days, was > that memcpy() didn't ever handle overlapped memory buffers and that you > should consider memmove() in such cases.
Yes, that's correct, and in fact we're replacing all uses of memcpy() with memmove() in upcoming releases. Oddly enough, I benchmarked both routines in the newest version of glibc on amd64, and found that memmove() consistently runs about 35% faster than memcpy(). So it's both safer *and* faster. On most platforms, memcpy() does work safely with overlapping buffers, but the POSIX standard doesn't require it to do so, and you're not supposed to rely on it. We had a coding error that caused such a copy, but there were no bad effects, so we missed it -- until glibc changed their memcpy() and revealed our mistake. (And we would've gotten away with it, too, if it wasn't for those meddling kids.) -- Evan Hunt -- e...@isc.org Internet Systems Consortium, Inc. _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
