I believe the way out of this 'who should do it?' problem is to only place those functions that are uniquely OS-related into POSIX. They are 'time()' and 'stime()'. Our task would then be to decide what arguments they take and what errors are defined. X3J11 should deal with the C library functions -- those in section 3 of some Unix manuals. This isn't an adequate definition of a "C library function". "getpwent" is in section 3 of some UNIX manuals, but it is definitely not a C function. Additional functions can be created within the domain of X3J11 but these should not be required for POSIX. As Robert Elz and others pointed out, POSIX should be the base on which different language environments may run. Imagine how a program would be written using Pascal's date/time manipulation functions. There probably won't be an asctime() call. I wouldn't bet on that. There may have to be some equivalent procedure; Pascal doesn't *have* any date/time manipulation functions. Frankly, I don't think C should have them, either. The standard UNIX library is called the "C library", but this is a misnomer. It contains some functions that may be considered language support for C, some functions that can be considered part of the operating system, and some functions that are really just useful utilities. The Standard I/O library routines are probably best considered to be language support for C (one might also consider them to be part of the operating system, except that the same interfaces have been implemented under other operating systems, and the intent seems to be that all C implementations should have those routines). "open" is clearly part of the operating system, as is "getpwent". "lsearch" is clearly just a utility; the code for "lsearch" could be transplanted to another OS with no trouble (except for possibly writing a "memcpy" routine), and could also be rewritten in any other language that supports the requisite data types. Neither POSIX nor X3J11 includes "lsearch". Although this means that portable code can't use it (or other potentially more interesting utility routines), this is arguably the correct thing to do. However, X3J11 includes some routines that could be considered utility routines or operating system interfaces. The date/time conversion routines fall into these categories: If the format of a "time_t" is considered to be a characteristic of the operating system (since, in most cases, it is the OS that supplies date/time information), "localtime" and "gmtime" are really operating system interfaces. "asctime" is clearly a utility, since it can be expressed in any sufficiently expressive language in an operating-system independent fashion (note that, in fact, a portable implementation of "asctime" is published as part of the current X3J11 draft!). The same is true of "ctime" (for which a portable implementation is also published). "strftime" could also be considered a utility routine, except that it is dependent on the "locale", which is currently considerered part of the C environment. As long as the "locale" is considered part of the C environment, and *not* a part of the operating system, "strftime" should be a part of the C standard. If the ANSI C standard included a definition of low-level routines for obtaining, say, the locale's full name for a month, given a month number of that month, "strftime" could also be written in portable ANSI C and published in the X3J11 draft. It does not include any OS dependencies. I would argue that this sort of "internationalization" belongs neither in an OS standard nor in a language standard; there should be a separate standard which, like e.g. various graphics standards, has bindings for several languages and can be implemented under various OSes. I'm not sure *where* the time-related stuff (i.e., the stuff that deals with "struct tm" values) belongs, although I'd argue in favor of putting it in POSIX. Unfortunately, I don't think the time-related and internationalization stuff is going to be moved out of ANSI C, and I'm also not sure how to split the OS-related and internationalization-environment-related time handling stuff between POSIX and some C-language or other-language binding of an internationalization standard.