title: Is there a tool to list global variables used and output by a C function?
body: <p>I want to make a list of global variables/macros consumed by a function and output by the function. For example, for:</p>
  
  <pre><code>void myfn(void) {
    out1 = in + 1;
    out2 = 2;
  }
  </code></pre>
  
  <p>..the tool would list the inputs as 'in' and the outputs as 'out1' and 'out2'.</p>
  
  <p>Does anyone know of such a tool?</p>