I APIs. </p>
<p>If the given <code>apis</code> parameter is null, returns the number of available APIs. Otherwise, fill the given apis array with the <a class="el" href="classRtMidi.html#aac66af04a85fe5c5f07c360574a19406" title="MIDI API specifier arguments.">RtMidi::Api</a> values.</p>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramname">apis</td><td>An array or a null value. </td></tr>
    <tr><td class="paramname">apis_size</td><td>Number of elements pointed t