t">   * state variables as arguments.</span>
<span class="comment">   */</span>
  <span class="keywordflow">while</span>(1) {
    protothread1(&amp;pt1);
    protothread2(&amp;pt2);
  }
}
</pre></div><h2><a class="anchor" name="example-code-lock">
A code-lock</a></h2>
This example shows how to implement a simple code lock - the kind of device that is placed next to doors and that you have to push a four digit number into in order to unlock the door.<p>
The code lock waits for key presses from a nu