HPUX

From PortaWiki

There can be Data Alignment fun - but these can also show up on PPC32

gcc 4.0.0 with high optimization levels seems to generate broken code on HPPA. Known to cause problems for OpenSSL.

shadow password support and IPv6 support are both run-time installable options, so if appropriate make sure you can fall back gracefully.

vsnprintf

On overflow, vsnprintf returns the number of bytes returns the number of bytes actually written, not the number of bytes that should have been written. (Tested on HP-UX 11.11, believed to be true on other versions too.)