Hum, Consider the following application (running on Linux with GCC): === BEGIN CODE #include <boost/regex.hpp> #include <iostream> #include <exception> #include <typeinfo> int main() { try { std::string rx_string = "^([[:alpha:]][-[:alnum:]]*[[:space:]]*)+$"; boost::regex rx(rx_string, boost::regex_constants::char_classes | boost::regex_constants::intervals); std::string test = "GlobalMSG HelpServ DevNull"; if (boost::regex_match(test, rx)) std::cout << "Matched." << std::endl; else std::cout << "Not Matched." << std::endl; } catch (const std::exception &e) { std::cout << "Exception " << typeid(e).name() << ": " << e.what() << std::endl; } return 0; } === END CODE The result of running this is: Exception N5boost14bad_expressionE: Memory exhausted My question is, why? The regex is simple enough, and the source string is quite short. Please note, the same regex with the test string of: "OperServ Magick-1" runs and completes successfully without a problem. Any ideas on how to fix this? -- PreZ :) Founder. The Neuromancy Society (http://www.neuromancy.net)