Patrick Loney wrote:
Using these two isn’t perfect but better than going back to epoch:
tm to_tm(ptime);
time_t mktime ( struct tm * timeptr );
That's probably fairly inefficient. Part of the reason this isn't in the library is that there's a number of safety issues when converting back to time_t (and it hasn't come up much). The code below points out those issues. This code is completely untested: //! Function that converts a ptime into a time_t inline std::time_t to_time_t(ptime t) { //if ptime is not_a_date_time or an infinity there's no conversion if (t.is_special()) { throw some_exception_type("conversion undefined"); } ptime time_t_epoch(gregorian::date(1970,1,1)); //if ptime is less than 1970-1-1 conversion will fail if (t < time_t_epoch) { throw some_exception_type("conversion undefined -- less than valid time_t epoch"); } time_duration td = t - time_t_epoch(); //cast likely needed to down covert from 64 to 32 bit rep //NOTE: all fractional seconds are truncated below... return static_caststd::time_t(td.total_seconds()); } HTH, Jeff