Can I embed ##ifdef in a macro?

[Vovin]

Hi,

I have a macro of the form:

#define MACRONAME (expr) OTHER_MACRO_TO_CALL (expr)

however I only want the macro OTHER_MACRO_TO_CALL to be called if a certain token is already defined. For example something like this:

#define MACRONAME (expr) \
#ifdef MY_TOKEN \
OTHER_MACRO_TO_CALL (expr) \
#endif

This however doesn't work. Is there any way of doing this? Any help would be much appreciated. Thanks.

 

[xwb]

How about inverting the condition

#ifdef MY_TOKEN
#define MACRONAME(expr) OTHER_MACRO_TO_CALL(expr)
#else
#define MACRONAME(expr)
#endif

 

[Vovin]

Thanks that works fine.