rem: util::time_conversion_helper compilation_time(__DATE__ " " __TIME__);
add: cpplexer::slex::util::time_conversion_helper compilation_time(__DATE__ " " __TIME__);
context: int print_version(){// get time of last compilation of this fileutil::time_conversion_helper compilation_time(__DATE__ " " __TIME__);// calculate the number of days since Dec 13 2001 // (the day the cpp project was started)std::tm first_day;    std::memset (&first_day, 0, sizeof(std::tm));    first_day.tm_mon = 11;           // Dec    first_day.tm_mday = 13;          // 13    first_day.tm_year = 101;         // 2001long seconds = long(std::difftime(compilation_time.get_time(),     std::mktime(&first_day)));    cout         << CPP_VERSION_MAJOR << '.'         << CPP_VERSION_MINOR << '.'        << CPP_VERSION_SUBMINOR << '.'        << seconds/(3600*24);       // get number of days from seconds    return 1;                       // exit app}