Unix and C are very tightly interwoven. Trying to separate them to form two standards is very much a Gordian (Ritchian?) Knot. In my last message I proposed dividing the many date/time related functions by the rule of 'is it Unix-based or language-based?'. And I meant by a call being in Man Section 3 as roughly the same as the latter. This message has more detail. Putting the choices into columns: Unix-based either-one language-based time() ftime() asctime() times() tzset() ctime() stime() time_t gmtime() utime() localtime() difftime() mktime() struct tm X3J11's date formatting functions Do these groupings make sense? Where should the 'either-one' functions be placed? Arguments can be made for putting them on both ends of the spectrum. Here are a couple of examples to show how various vendors with wildly different OSs dealt with the problem of what to put in their C libraries. VMS: Base OS has a 64-bit representation of time that is the number of 100 nanoseconds periods since 00:00 on November 17, 1858. HAS: ctime(), ftime() [but TZ and DST are zero], localtime() [isdst=0] time() [seconds since 00:00 UT 1/1/70], and times() [the sys fields=0] MISSING: asctime(), gmtime(), stime(), utime() DOS: Base OS keeps track of time since 1/1/80 HAS: asctime(), ctime(), difftime(), ftime(), gmtime(), localtime(), tzset(), time() [returns seconds since 00:00 UT 1/1/70], utime(), and times() MISSING: stime() DOS's functions won't give back a formatted string for any time before 1/1/80, ie, long t=12345; ctime(&t) gives back 1/1/80 even though t is referring to a day in 1970.