   Help with header files...
  Game Programming Gurus,Let''s say I have a header file that contains some global variables that I want to have access to in multiple modules.  When I include (#include "globals.h") in each module I get errors about objects being defined more than once.  For example:Lets say that I declare the following variable in globals.hHWND main_window_handle;Now I include this header in my module where I create the basic Win32 Window.I also need to have the main_window_handle when I setup Direct Draw, so I include global.h in my DD module.  That is where I run into problems.Is there a way to include the same headers in multilpe modules and not have the linker crap out on variable I have declared there?  
  /* Header.h */#ifndef INC_HEADER_H#define INC_HEADER_Hextern int Magic;#endif/* Header.c */#include "Header.h"int Magic = 12345;/* Main.c */#include "Header.h"#include <stdio.h>int main(void) {    printf("%d\n",Magic);    return 0;}   ;  #ifndef SOME_DEFINE#define SOME_DEFINE// Variables/whatnot of your global.h#endif