Would there be a way to do some "ifdef" inside a macro?
Could be in the form of a macro taking 3 args, - 1st being the macro to test the existance of, - 2nd being the value to expand in case 1st arg is a defined macro - 3rd being the value to expand in case 1st arg is not a defined macro
Not really. You can test whether a macro expands to 0 or 1 though.
Yes, I've seen that. I think I've also seen the possibility to test wether it expends to 0 or any number from 1 to some maximum. And some people here also talked about chaos. It seems that it also alowsto test wether a macro expands to "0 and nothing (i.e. a placemarker)" (chaos_pp_placemarker_if) It is described as C99 specific (I suppose it uses __VA_ARGS__). But what I would like is to expand to some value by default and another if a given macro is set. Thanks for your answer.