https://svn.boost.org/trac10/ticket/269 <pre class="wiki">I am looking for regular expression "http://\([^ ]+\)+" in a buffer containing following text http://business.jet2web.at. and it failes in file "perl_matcher_non_recursive.hpp" function match_all_states() { ...... if(state_count &gt; max_state_count) raise_error(traits_inst, REG_ESPACE); } I work with bersion BOOST 1.31 in Visual Studio .NET 2003. My User.hpp is attached. I set following flags of compilation: boost::regbase::flag_type reg_flags = boost::regbase::char_classes | boost::regbase::escape_in_lists | boost::regbase::bk_parens | boost::regbase::intervals; Maya </pre> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/269 Trac 1.4.3 John Maddock Fri, 14 May 2004 12:40:14 GMT https://svn.boost.org/trac10/ticket/269#comment:1 https://svn.boost.org/trac10/ticket/269#comment:1 <ul> <li><strong>status</strong> <span class="trac-field-old">assigned</span> → <span class="trac-field-new">closed</span> </li> </ul> <pre class="wiki">Logged In: YES user_id=14804 It's not a bug (honest), the basic problem is that your expression is basically the same form as: (.*)* which is known to become pathological very quickly; the thrown exception is intended to prevent the expression from taking an eternity trying to find a match. The alternative expression: "http://\([^ ]+\)" would actually do exactly the same thing, but does not get pathological. John Maddock </pre> Ticket