ith the format
                    string <span class="emphasis"><em>fmt</em></span>. Uses <span class="emphasis"><em>flags</em></span>
                    to determine what gets matched, and how the format string should
                    be treated. If <span class="emphasis"><em>copy</em></span> is true then all unmatched
                    sections of input are copied unchanged to output, if the flag
                    <span class="emphasis"><em>format_first_only</em></span> is set then only the first