hello (and thanks for previous help!), I'm having some difficulty accessing the location of the beginning of a successful partial match. in the callback below, match_results.position() does give me the index of successful matches. How do i get it for partial? The code does recognize a partial match but what[0].first seems to be undefined on a partial match. The callback is called 3 times and does identify the partial but have been totally unable to get that index..Code is below, thanks alot! Dave bool regex_callback(const boost::match_results<std::string::const_iterator>& what) { cout << "in callback, index is " << what.position(0) << endl; if(!what[0].matched) cout << "|--is partial " << endl; return true; } int main(int argc, char *argv[]) { string sMatchMe = "HELLO"; int theseflags=0; boost::regex xreMatchme(sMatchMe, theseflags); boost::cmatch xcmMatch; string stupid = "sdfaHELLOdsfh*saHELLOdhfas1d3ahsdf%as&d!adfasdfsdHELL"; boost::sregex_iterator m1(stupid.begin(), stupid.end(), xreMatchme, boost::match_default | boost::match_partial); boost::sregex_iterator m2; std::for_each(m1, m2, ®ex_callback); return 1; }