How to define a define in C?

Question

Is it possible to write a #define that defines a #define?

For example:

#define FID_STRS(x) #x
#define FID_STRE(x) FID_STRS(         


        

Answer 1

No; preprocessing is performed in a single pass. If you want or need more advanced behavior, consider using another tool to preprocess the source, like m4.

Further, the # in the replacement list (at the beginning of #define FIDN... would be parsed as the # (stringize) operator: the operand of this operator must be a named macro parameter, which define is not.