<p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated by
            <code class="function">glUnmapNamedBuffer</code> if
            <em class="parameter"><code>buffer</code></em> is not the name of an existing
            buffer object.
        </p>
        <p>
            <code class="constant">GL_INVALID_OPERATION</code> is generated if the
            buffer object is not in a mapped state.
        </p>
      </div>
      <div class="refsect1" id="associatedgets">
        <h2>A