f an error occurs, all non-<code>NULL</code> position arguments will be set to zero.</p>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramdir">[in]</td><td class="paramname">monitor</td><td>The monitor to query. </td></tr>
    <tr><td class="paramdir">[out]</td><td class="paramname">xpos</td><td>Where to store the monitor x-coordinate, or <code>NULL</code>. </td></tr>
    <tr><td class="paramdir">[out]</td><td class="paramname">ypos</td><td>Where to store the monit