><code>params</code></em>.  For input and output variables with a component
            specified by a <code class="code">layout</code> qualifier, the specified component is written.
            For all other input and output variables, the value zero is written.
        </p>
        <p>
            For the property <code class="constant">GL_TRANSFORM_FEEDBACK_BUFFER_INDEX</code>, a single integer
            identifying the index of the active transform feedback buffer associated
            with an active