r in the currently installed program object.
        </p>
        <p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <em class="parameter"><code>mode</code></em> is <code class="constant">GL_PATCHES</code>
            and no tessellation control shader is active.
        </p>
        <p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if <a class="citerefentry" href="glEndTransformFeedback"><span class="citerefentry"><span class="refentrytitle">glE