C :: Defining And Using A Macro

I am trying to create a small set of filepath functions that I intend to compile across linux and windows (I prefer not to use a big library). I want to have a global constant PATH_SEPARATOR that depends on the OS environment. This is what I set at the top of header file.

Code:

#include <stdio.h>
const char PATH_SEPARATOR =
#ifdef _WIN32
'';
#else
'/';
#endif I was hoping to test this while compiling this in a linux environment using gcc, thusly:

Code:

int main (int argc, char const* argv[])
}

[code]....

where apparently, I seem not to be able to "set" a part of the code to have "_WIN32" defined. I don't know if I explained this clearly.