title: Optional arguments in C function
body: <p>In a C function, I want to check if an input argument ('value' in my case) is presented or not.</p>
  
  <p>i.e.:</p>
  
  <pre><code>void Console(char string[], int32_t value)
  {
      // write string here
      // write value here, if it exists
  }
  </code></pre>
  
  <p>When used <code>if(value != NULL)</code> statement, my Console() function sends 4096</p>
  
  <p>How can I check and act based on argument existence?</p>