title: Detecting 64bit compile in C
body: <p>is there a C macro or some kind of way that i can check if my c program was compiled as 64bit or 32bit at compile time in C?</p>
  
  <p>Compiler: GCC
  Operating systems that i need to do the checks on: Unix/Linux</p>
  
  <p>Also how could i check when running my program if the OS is capable of 64bit?</p>