Why doesn’t OS X support POSIX.1b?  No, really?

I’m working on writing a threadsafe compiler as part of my research project this summer.  The RTS extensions allow you to send an integer or pointer along with a signal (via the sigqueue function).  Unfortunately, sigqueue and much of RTS is missing from OS X Leopard, as it’s an optional part of the SUS / UNIX 03 spec.

The really odd thing is that it implements enough of POSIX.1b to receive integers/pointers from a sending process, but not enough to send them.  WTF?

Any thoughts on portably sending an integer value between process in a high-performance way?  Pipes just don’t seem as clean as a sigqueue call…