Looking for #ifdef type behavior for an include file

[DanSut]

I have been creating an include file for a bunch of UDFs that give me a cleaner interface to a bunch of functions in a DLL - that bit is working fine.

I would like to cause these functions to do nothing if I defined something before the #include - a similar action to substituting a different include file with the same functions defined but with them all empty.

In C like languages I would use a #ifdef but I can't find anything like that in AutoIt's language. If thought there might be some way to test if a variable had been defined, using one undefined seems to just give an error though. Thought there might be an exists($varname) or defined($varname) but I also can't find anything like that I feel sure that there must be some way of achieving my goal without having real and null versions of the include that I switch in and out - I seem to just not be thinking too clearly.

All the terms I can think of to search on seem to get me a million answers all of which are unrelated to my goal - I guess the terms are just too generic in a programming environment. All suggestions will be gratefully received