#ifdef inside #define

I am trying to write something like this:

#define COV_ON(x) \
                #ifdef COVERAGE_TOOL \
                    _Pragma (COVERAGE #x)
                #endif

Is there any way to define COV_ON like this? I know what I have done above is wrong as I can't have #ifdef inside #define. (# is not an allowed character in #define). So is there any solution?

Solution 1:

Not possible. Do it the other way around:

#ifdef COVERAGE_TOOL
#define COV_ON(x) _Pragma (COVERAGE #x)
#else
#define COV_ON(x)
#endif

Solution 2:

Simply turn it around:

#ifdef COVERAGE_TOOL
#define COV_ON(x) _Pragma (COVERAGE #x)
#else
#define COV_ON(x) /* foo */
#endif