Why and when to use __noop?

Question

I was reading about __noop and the MSDN example is

#if DEBUG
   #define PRINT   printf_s
#else
   #define PRINT   __noop
#endif

int main() {
   PRINT(\"\\nhello         


        

Answer 1

#define PRINT
extern int some_complicated_calculation();
PRINT("%d\n", some_complicated_calculation());

would call the function even though you don't want the result.

Using __noop, the function won't be called.

You could (assuming the compiler supports variadic macros) define PRINT to ignore the arguments; but then they won't be parsed at all, and may become invalid if you change the code around them without compiling the variant that defines PRINT to do something. Using __noop, the arguments are still parsed, so are more likely to remain valid.