de> options when constructing
        the regular expression, in particular note that the <a class="link" href="../ref/syntax_option_type/syntax_option_type_extended.html" title="Options for POSIX Extended Regular Expressions"><code class="computeroutput"><span class="identifier">newline_alt</span></code></a> option alters the syntax,
        while the <a class="link" href="../ref/syntax_option_type/syntax_option_type_extended.html" title="Options for POSIX Extended Regular Expressions"><code class="compute