Hi, I'm new to boost and not all that familiar with Perl regex. However, I have my own code for using Perl regex libraries for finding interesting features in DNA ( http://www.mail-archive.com/bio_bulletin_board@bioinformatics.org/msg01382.h... ) I recently added boost to work along with Microsoft's greta code. However, I now have a problem with regex exploding. The questionable regex is presumably, (?<=GU.*?TACTAAC.{20,40}AG|^).*?(?=GU.*?TACTAAC.{20,40}AG|$) ( which doesn't explode with greta AFAIK) and the code in question is ( MM_MARK is debug macro, es is error stream other stuff omitted). try { es<<MM_MARK<<" "<<" "<<'\n'; boost::regex expression(query); [...] es<<MM_MARK<<" "<<" "<<'\n'; [ ...] } catch ( boost::regex_error e) { es<<MM_MARK<<" Error code "<<e.code()<<" at "<<e.position()<<'\n'; es<<MM_MARK<<query<<'\n'; return -1; } catch (exception e) { es<<MM_MARK<<" "<<e.what()<<'\n'; es<<MM_MARK<<" at "<<(start-sample)<<" for regex "<<query <<".\n"; } catch (...) { es<<MM_MARK<<" "<<"Unknown exception \n";} return -1; } I have two questions, what is wrong with the regex and how do I trap the error? The program just dies with "Aborted( core dump)." I guess there could be a build problem but I thought it may be something obvious that I am doing wrong in the regex or calling the library. Thanks. Mike Marchywka 586 Saint James Walk Marietta GA 30067-7165 404-788-1216 (C)<- leave message 989-348-4796 (P)<- emergency only marchywka@hotmail.com Note: Hotmail is blocking my mom's entire ISP claiming it is to reduce spam but probably to force users to use hotmail. Please DON'T assume I am ignoring you and try me on marchywka@yahoo.com if no reply here. Thanks. _________________________________________________________________ Test your celebrity IQ. Play Red Carpet Reveal and earn great prizes! http://club.live.com/red_carpet_reveal.aspx?icid=redcarpet_hotmailtextlink2