

<span class="preprocessor">#include &lt;stdio.h&gt;</span> <span class="comment">/* For printf(). */</span>

<span class="comment">/* Two flags that the two protothread functions use. */</span>
<span class="keyword">static</span> <span class="keywordtype">int</span> protothread1_flag, protothread2_flag;
<span class="comment"></span>
<span class="comment">/**</span>
<span class="comment"> * The first protothread function. A protothread function must always</span>
<span class="comment"> * return an