I just wanted to start writing a ISO 8601 subset -> time_t conversion routine, but to my great disappointment I discovered that ISO C does not seem to allow portable conversion of a broken-down time into time_t. In other words, while mktime() is the inverse function to localtime(), there exists no mkgmtime() that is the inverse function to gmtime(). I knew that the C standard library time API is a strange design, but I had no idea that it was *that* bad. The only practical way to get from a broken-down UTC time to time_t seems to be to assume that we are on a POSIX system where the time_t representation is exactly specified. Or did I miss something? In case someone of you is in contact with the folks revising ISO C, I have now a whole list of things that should be fixed in time.h: - add inverse function for gmtime() (mkutime() or mkgmtime()) - add to strftime() conversion specifiers for ISO 8601 week-of-year and year-of-week. - remove the second leap second 61 mentioned in the footnote (contradicts to UTC definition) Instead of adding an inverse function for gmtime, one could also extend struct tm by a new field tm_offset, which is in seconds the difference between the time in the struct tm and the corresponding universal time (in my opinion a much cleaner solution than the tm_isdst hack). But I guess, this might break existing code that does not initialize tm_offset ... Having a tm_offset in struct tm would however still be a good idea as this would allow to implement in strftime() conversion specifiers for the time zone offset (much more interesting than the time zone name). Markus -- Markus G. Kuhn, Computer Science grad student, Purdue University, Indiana, USA -- email: kuhn@cs.purdue.edu