       </p>
        <p>
            If <em class="parameter"><code>barriers</code></em> is <code class="constant">GL_ALL_BARRIER_BITS</code>, shader memory accesses
            will be synchronized relative to all the operations described above.
        </p>
        <p>
            Implementations may cache buffer object and texture image memory that
            could be written by shaders in multiple caches; for example, there may be
            separate caches for texture, vertex fetching, and one or more