Thanks John, spot on. I've used a new iterator variable for the result of regex_search and it works now. Now the code is: if (regex_search(what[1].str(),what2,attrMarkup)) {

There's at least one issue with your code, in: if (regex_search(what[1].str(),what,attrMarkup)) { the result of what[1].str() is a temporary string object: by the time the call returns the object has gone out of scope, and the iterators stored in "what" are invalid. HTH, John.

Diego -- Do you want to know what is going on in Language Technology in Australia and New Zealand? Join ALTA -- http://www.alta.asn.au/ This message is intended for the addressee named and may contain confidential information. If you are not the intended recipient, please delete it and notify the sender. Views expressed in this message are those of the individual sender, and are not necessarily the views of Macquarie University. --------------------------------------------------------------------- Diego MOLLA ALIOD diego@ics.mq.edu.au Department of Computing http://www.ics.mq.edu.au/~diego Macquarie University