Date: Wed, 07 Oct 1998 11:35:13 +0100 From: Markus Kuhn <Markus.Kuhn@cl.cam.ac.uk> Paul Eggert wrote on 1998-10-07 09:01 UTC:
I would like the spec to be modified so that xtime_get(TIME_MONOTONIC) can be compiled to a single instruction accessing the hardware clock register directly, which will make sub-ns access more practical.
Don't forget that the old clock_t clock(void); is still available It's available, but it wouldn't work well, for three reasons. First, `clock' reports the sum of the CPU times of the process and its children; this is not the same as TIME_MONOTONIC. Many applications need high-precision real-time clocks, not CPU-time clocks. Second, on my host (Solaris 2.6) `clock' is already defined to return a 32-bit microsecond counter, and it will be inconvenient to change this to a 64-bit or larger counter, due to backward compatibility concerns. Third, the struct xtime spec deprecates both clock_t and `clock'. One of the goals of struct xtime -- a goal that I agree with -- is to supersede `clock'.