#define MACRO_USES_CONCAT_FUNCTION CONCAT_FUNCTION(PREFIX, SUFFIX())
            #ifdef _MSC_VER // only for Visual C++
                #define MACRO_PRODUCES_FUNCTION_CALL CONCAT_FUNCTION(FUNCTION_RETURNS_ARG, ARGS)
            #else
                #define MACRO_PRODUCES_FUNCTION_CALL "hello.h" // ignore
            #endif
            #include ${macro}
            #include <iostream>

            int main () {