Re: [PATCH] 'select' failure or signal should not update timeout

[linux@horizon.com]

Chris Friesen asked for:
> waitonmonotonicallyincreasingnonadjustablehighres64bittime()

Well, take the POSIX clock_gettime() interface and add clock_waittime().
Oh, wait.. they already did it.  clock_nanosleep().

The POSIX folks realized that people want a variety of tiemrs, and
so the functions take a clockid_t first argument, which is just an enum.
They defined two values, but leave the field open to others:
- CLOCK_MONOTONIC, which is what you want.  Unspecified epoch
  (possibly boot time), and never gets adjusted
- CLOCK_REALTIME, which is the classig time() UTC time.

Extensions define CLOCK_PROCESS_CPUTIME_ID and CLOCK_THREAD_CPUTIME_ID.

The clock weenies are welcome to add CLOCK_TAI, CLOCK_GPS, CLOCK_UTS
(see Markus Kuhn's suggestion), CLOCK_UTC (with some "better" leap-second
handling), CLOCK_FREQADJUST (uses frequency but not phase adjustments),
CLOCK_NOSTEP (frequency and phase adjustments, but doesn't step),
and anything else you like.

Astronomers might add CLOCK_UT1, CLOCK_UT0, CLOCK_SIDERIAL, CLOCK_TDB,
CLOCK_TDT, CLOCK_TCG, CLOCK_TCB, and maybe a few things I haven't thought
of.  The interface doesn't require that all of these be implemented in
the kernel, of course.