[Haskell-cafe] Precise timing

[ok at cs.otago.ac.nz]

Jeffrey Brown wrote
> Also I did not understand
> until today that while Mac is a variety of Unix, it is not a variety
> of Linux.

There's a bunch of POSIX (well, SuSv4) features to do with
threads or scheduling that are missing in OS X.  In Apple's
defence, they are optional.  Examples include
sched_{get,set}{param,scheduler}, barriers, and spin locks.
I'm sure I've forgotten some.  Oh yeah, robust mutexes.
Several locking functions with timeouts too.

These are of course not the only differences.

There are apparently quite a few things that can be done nicely
in OS X using Mach facilities, but I have not yet succeeded in
finding useful documentation for Mach, which has probably kept me
out of more trouble than I realise.