Boost C++ Libraries: Ticket #13535: xpressive miss captured groups name while assign a match_results object to another. https://svn.boost.org/trac10/ticket/13535 <p> example: </p> <pre class="wiki"> cmatch match; cmatch mat2; cregex rex = tcompile("(?P&lt;ErrorCode&gt;\\d{5})"); if( regex_match("error10205",match,rex) ) { mat2 = match; string strErr = mat["ErrorCode"]; // Here will not get the match string } </pre><p> It's cause by funciton: <strong>void swap(match_results&lt;<a class="missing wiki">BidiIter</a>&gt; &amp;that)</strong> </p> <p> in <strong>match_results.hpp</strong> file. </p> <p> I had fix the bug, by adding </p> <h2 class="section" id="this-named_marks_.swapthat.named_marks_">this-&gt;named_marks_.swap(that.named_marks_);</h2> <p> after line 668. </p> en-us Boost C++ Libraries /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/13535 Trac 1.4.3