title: C : Function parameter with undefined type parameters
body: <p>How can I code a function that accept not defined parameters ?
  I imagine it could work like that :</p>
  
  <pre><code>void foo(void undefined_param)
  {
      if(typeof(undefined_param) == int) {/...do something}
  
      else if(typeof(undefined_param) == long) {/...do something else}
  }
  </code></pre>
  
  <p>I'have read that templates could maybe solve my problem, but in C++ and I need it in C.</p>
  
  <p>I'm just trying to avoid coding two functions with a lot of similar codes. In my case, I wont be looking for <code>int</code> or <code>long</code> but struct types that I defined.</p>