1 .\" $OpenBSD: clock_gettime.2,v 1.4 1997/05/08 20:21:16 kstailey Exp $
2 .\" $FreeBSD: src/lib/libc/sys/clock_gettime.2,v 1.3.2.8 2001/12/14 18:34:00 ru Exp $
3 .\" $DragonFly: src/lib/libc/sys/clock_gettime.2,v 1.6 2008/05/02 02:05:04 swildner Exp $
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39 .Nd get/set/calibrate date and time
45 .Fn clock_gettime "clockid_t clock_id" "struct timespec *tp"
47 .Fn clock_settime "clockid_t clock_id" "const struct timespec *tp"
49 .Fn clock_getres "clockid_t clock_id" "struct timespec *tp"
55 allow the calling process to retrieve or set the value used by a clock
60 can be one of two values:
62 for time that increments as a wall clock should and
64 for time that increments at a static rate in SI seconds.
66 The structure pointed to by
73 time_t tv_sec; /* seconds */
74 long tv_nsec; /* and nanoseconds */
78 Only the super-user may set the time of day.
79 If the system securelevel is greater than 1 (see
81 the time may only be advanced.
82 This limitation is imposed to prevent a malicious super-user
83 from setting arbitrary time stamps on files.
84 The system time can still be adjusted backwards using the
86 system call even when the system is secure.
88 The resolution (granularity) of a clock is returned by the
90 call. This value is placed in a (non-NULL)
95 The following error codes may be set in
101 was not a valid value.
105 argument address referenced invalid memory.
107 A user other than the super-user attempted to set the time.