hi all i am using boost regex to check the systax of my URLs. if i am giving a long URL then it is giving the following error:- terminate called after throwing an instance of 'boost::bad_expression' what(): Memory exhausted Aborted and the program is aboted. My code is this:- #include<iostream> #include <boost/regex/v4/regex.hpp> bool EvaluateRegex(const std::string regularexp,std::string url){ boost::smatch what; boost::regex exp(regularexp,boost::regex::extended); boost::regex_search(url,what,exp); std::string search=(std::string)what[0]; if(search.length() == url.length()) return true; else return false; } int main() { std::string url; const std::string URLSYNTAXREGEX = "((https?|ftp)://)?(((([a-zA-Z0-9]+-?)?[a-zA-Z0-9]+)+[.]{1}[a-zA-Z0-9]+)+([:]{1}((0[0-7]+)|(0[xX][0-9a-fA-F]+)|([0-9]+))){0,1})([?/][-a-zA-Z0-9+&@#/%?=~_|!:,.; ]*)?"; std::cout<<"enter the URL"<<std::endl; std::cin>>url; if(!EvaluateRegex(URLSYNTAXREGEX,url)) std::cout<<"Malformed URL"<<std::endl; else std::cout<<"Well formed URL"<<std::endl; return 0; } --------------------------------- Love cheap thrills? Enjoy PC-to-Phone calls to 30+ countries for just 2¢/min with Yahoo! Messenger with Voice.