/code> such
                  that <code class="computeroutput"><span class="special">!</span><span class="identifier">ec</span></code>
                  is true. If an error occurred, returns <code class="computeroutput"><span class="number">0</span></code>
                  and sets <code class="computeroutput"><span class="identifier">ec</span></code> such
                  that <code class="computeroutput"><span class="special">!!</span><span class="identifier">ec</span></code>
                  is true