title: How do I run the GCC preprocessor to get the code after macros like #define are expanded?
body: <p>Is there an option that the GCC preprocessor could generate C source code and filter out irrelevant source code?</p>
  
  <p>For example, a <code>.c</code> file has a <code>#define</code> switch to define for many different platforms. I'm only interested in one platform, and I want the C preprocessor to filter out unrelated code. </p>
  
  <p>Does <strong>GCC</strong> support this?</p>