Standards for C complex number routines - ARE THERE?

[Mike Rutenberg]

Are the any standards (IEEE, ANSI or other) for complex
number libraries in C?  Anything under development?

I'm just curious - I've done a short package in C which
works fine, but I would like to make it easy to port the code
to other machines which may have local super duper fast routines.
I'd rather comply now than later - I'm just that type I guess :-).

Mike