# ifdef usage

# ifdef _Win32
# include "stdio.h"
#endif

int main()
{
int i=10;
printf("I am in windows platform\n",printf("Hai "));
return 0;
}

OUTPUT:

1>c:\karthi\vsc\macros\macros\macro.c(8) : warning C4013: 'printf' undefined;

Note: 1. _Win32 is a label which is specifying the OS.