getpid() or something similar

[Peter Simons]

Hal Daume writes:

 > In GHC in the Posix module, there's GetProcessID:

Thanks for the pointer! 

Unfortunately, this is a GHC-only solution, which is really annoying
in my case because the software is completely compiler-independent,
and I don't want to restrict it to GHC because I need it to determine
a unique file name for a temporary file!

Is there no other way? I cannot be the first person ever to need a
temporary file, can I? Surely there must be some portable way, too?

Peter