title: Is there a #define for 64 bit in Visual Studio 2010?
body: <p>Is there a #define that indicates whether Visual Studio is compiling in 64bit mode? I'd like to be able to include some code conditionally like so</p>
  
  <pre><code>#ifdef _IS_64BIT
    ...
  #else //32 bit
    ...
  #endif
  </code></pre>
  
  <p>I know I can create a flag myself, but I'm wondering if the compiler provides one. </p>