       and that flag is reset to <code class="constant">GL_NO_ERROR</code>
            when <code class="function">glGetError</code> is called.
            If more than one flag has recorded an error,
            <code class="function">glGetError</code> returns and clears an arbitrary error flag value.
            Thus, <code class="function">glGetError</code> should always be called in a loop,
            until it returns <code class="constant">GL_NO_ERROR</code>,
            if all error flags are to be r