I am struggling with a regex in some code of mine. I want to use regex_search to look for a match in a std::string, but my code will not build. This is a snippet of what I am trying to do. using namespace std; string in_file_name_s; string date_and_time_s; string day_s; char input_line[5000]; boost::regex re_date_time("(.*-.*-.*:.*:.*),.*,.*,.*,.*,.*,.*,.*,.*,"); boost::regex re_pices_date_time("(.*)\\-(.*)\\-(.*) (.*)"); boost::cmatch match; while (inFile.getline(input_line , 5000)) { if (boost::regex_search(input_line, match , re_date_time )) { date_and_time_s = match[1]; if (boost::regex_search(date_and_time_s , match , re_pices_date_time )) { day_s = match[1]; } } } When I compile I get the following error error C2784: 'bool boost::regex_search(const std::basic_string &,const boost::basic_regex &,boost::regex_constants::match_flag_type)' : could not deduce template argument for 'const boost::basic_regex &' from 'boost::cmatch' The 1st regex_search looking at input_line char[] works Ok it's the 2nd one looking at date_and_time_s std::string that gets the error. If I remark out the 2nd one the program builds and I watch the input_line doing what it should in the debugger. Also this code used to work before I upgraded from Visual C++6 to Visual C++8 and from bost_1_33_1 to boost_1_34_0. I don't know if it was the change in compiler or the boost lib that broke this. Thanks in advance for your help. Troy