Getting "absolute time" in Linux - comp.os.linux.development.system

Message from discussion Getting "absolute time" in Linux

malc

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More options Nov 15 2006, 10:42 am

Newsgroups: comp.os.linux.development.system

From: malc <m...@pulsesoft.com>

Date: Tue, 14 Nov 2006 23:42:09 +0000 (UTC)

Local: Wed, Nov 15 2006 10:42 am

Subject: Re: Getting "absolute time" in Linux

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Boris Benenson <boris.benen...@marconi.com> writes:
> Is there a way in either standard or Real-time Linux to get "absolute
> number of ticks (or seconds) since the Epoc (or some other
> configurable starting point), regardless of the kernel clock resets
> via settimeofday() and the RTC resets via hwclock set and regardless
> of the system reboots?

http://www.opengroup.org/onlinepubs/000095399/functions/clock_gettime...
CLOCK_MONOTONIC

`man clock_gettime' on this Linux box says:

AVAILABILITY
On POSIX systems on which these functions are available,
the symbol _POSIX_TIMERS is defined in <unistd.h> to a
value greater than 0. The symbols _POSIX_MONOTONIC_CLOCK,
_POSIX_CPUTIME, _POSIX_THREAD_CPUTIME indicate that
CLOCK_MONOTONIC, CLOCK_PROCESS_CPUTIME_ID,
CLOCK_THREAD_CPUTIME_ID are available. (See also
sysconf(3).)

Availablility of CLOCK_MONOTONIC is system (and not just libc)
specific (for instance stock Linux 2.4 kernels do not have it,
2.6 do)

--
vale

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