cpp state

Hi-

I don't suppose there's any way to access the state of the preprocessor 
following an invocation? I'm looking for a way to read a header file 
(for example) and determine what defines are present and their values. I 
suppose I can append some pike-code to the string in question and use 
that to populate variables which can then be evaluated, but what would 
only work if I already know the name of the define I'm looking for.

I don't recall this being available, but thought I'd ask. Happy to hear 
any suggestions!

Bill