-zA-Z0-9_]+[.]{1})+(([-a-zA-Z0-9]+))([:]{1}([0-9]+)){0,1})([?/][^[:space:]]*)?"

the function for evaluation is:-

bool URLHandler::EvaluateRegex(const char *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;
        }
}

when i am running this code with single thread it is running fine. But when i am integrating this code with a multithreaded application it is giving this error:-

terminate called after throwing an instance of 'boost::regex_error'
what(): Invalid content of repeat range
Aborted

Can you please help me in this. Its very urgent for me.

Thanks.
Yogendra