l <I>x</I> is greater than <I>y</I> is performed as
follows: 
</BLOCKQUOTE>
<PRE STYLE="margin-left: 1.01cm">pthread_mutex_lock(&amp;mut);
while (x &lt;= y) {
        pthread_cond_wait(&amp;cond, &amp;mut);
}
/* operate on x and y */
pthread_mutex_unlock(&amp;mut);</PRE><BLOCKQUOTE STYLE="margin-left: 3.01cm">
Modifications on <I>x</I> and <I>y</I> that may cause <I>x</I> to
become greater than <I>y</I> should signal the condition if needed: 
</BLOCKQUOTE>
<PRE STYLE="margin-left: 1.01cm">pthread_mutex_lock