clock_getres(2) [netbsd man page]

CLOCK_SETTIME(2)					      BSD System Calls Manual						  CLOCK_SETTIME(2)

NAME

     clock_settime, clock_gettime, clock_getres -- clock and timer functions

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <time.h>

     int
     clock_settime(clockid_t clock_id, const struct timespec *tp);

     int
     clock_gettime(clockid_t clock_id, struct timespec *tp);

     int
     clock_getres(clockid_t clock_id, struct timespec *res);

DESCRIPTION

     The clock_settime() function sets the clock identified by clock_id to the absolute time specified by tp.  If the time specified by tp is not
     a multiple of the resolution of the clock, tp is truncated to a multiple of the resolution.

     The clock_gettime() function stores the time of the clock identified by clock_id into the location specified by tp.

     The clock_getres() function stores the resolution of the clock identified by clock_id into the location specified by res, unless res is NULL.

     A clock_id of CLOCK_REALTIME identifies the realtime clock for the system.  For this clock, the values specified by clock_settime() and
     obtained by clock_gettime() represent the amount of time (in seconds and nanoseconds) since 00:00 Universal Coordinated Time, January 1,
     1970.

     A clock_id of CLOCK_MONOTONIC identifies a clock that increases at a steady rate (monotonically).	This clock is not affected by calls to
     adjtime(2) and settimeofday(2) and will fail with an EINVAL error if it's the clock specified in a call to clock_settime().  The origin of
     the clock is unspecified.

     If the calling user is not the super-user, then the clock_settime() function in the standard C library will try to use the clockctl(4) device
     if present, thus making possible for non privileged users to set the system time.	If clockctl(4) is not present or not accessible, then
     clock_settime() reverts to the clock_settime() system call, which is restricted to the super user.

RETURN VALUES

     A value of 0 is returned on success.  Otherwise, a value of -1 is returned and errno is set to indicate the error.

ERRORS

     The clock_settime(), clock_gettime() and clock_getres() functions will fail if:

     [EINVAL]		The clock_id argument does not specify a known clock.

     [ENOSYS]		The function is not supported by this implementation.

     The clock_settime() function will fail if:

     [EINVAL]		The tp argument is outside the range for the specified clock, clock_id.

     [EINVAL]		The tp argument specified a nanosecond value less than zero of greater than or equal 1000 million.

     [EINVAL]		The clock_id argument is a clock that can not be adjusted.

     [EPERM]		The calling process does not have the appropriate privilege to set the specified clock, clock_id.

     The clock_gettime() function will fail if:

     [EFAULT]		The tp argument specifies an address that is not a valid part of the process address space.

SEE ALSO

     ctime(3), time(3), clockctl(4)

STANDARDS

     The clock_settime(), clock_gettime() and clock_getres() functions conform to IEEE Std 1003.1b-1993 (``POSIX.1'').

BSD
								 February 11, 1999							       BSD

clock_settime(3C)					   Standard C Library Functions 					 clock_settime(3C)

NAME

       clock_settime, clock_gettime, clock_getres - high-resolution clock operations

SYNOPSIS

       #include <time.h>

       int clock_settime(clockid_t clock_id, const struct timespec *tp);

       int clock_gettime(clockid_t clock_id, struct timespec *tp);

       int clock_getres(clockid_t clock_id, struct timespec *res);

DESCRIPTION

       The clock_settime() function sets the specified clock, clock_id, to the value specified by tp. Time values that are between two consecutive
       non-negative integer multiples of the resolution of the specified clock are truncated down to the smaller multiple of the resolution.

       The clock_gettime() function returns the current value tp for the specified clock, clock_id.

       The resolution of any clock can be obtained by calling clock_getres(). Clock resolutions are  system-dependent  and  cannot  be	set  by  a
       process.  If  the  argument  res  is not NULL, the resolution of the specified clock is stored in the location pointed to by res. If res is
       NULL, the clock resolution is not returned. If the time argument of clock_settime() is not a multiple of res, then the value  is  truncated
       to a multiple of res.

       A clock may be systemwide (that is, visible to all processes) or per-process (measuring time that is meaningful only within a process).

       A  clock_id  of	CLOCK_REALTIME is defined in <time.h>. This clock represents the realtime clock for the system. For this clock, the values
       returned by clock_gettime() and specified by clock_settime() represent the amount of time (in seconds and  nanoseconds)	since  the  Epoch.
       Additional clocks may also be supported. The interpretation of time values for these clocks is unspecified.

       A  clock_id  of	CLOCK_HIGHRES  represents  the non-adjustable, high-resolution clock for the system. For this clock, the value returned by
       clock_gettime(3C) represents the amount of time (in seconds and nanoseconds) since some arbitrary time in the past; it is not correlated in
       any  way  to  the  time of day, and thus is not subject to resetting or drifting by way of adjtime(2), ntp_adjtime(2), settimeofday(3C), or
       clock_settime().  The time source for this clock is the same as that for gethrtime(3C).

       Additional clocks may also be supported. The interpretation of time values for these clocks is unspecified.

RETURN VALUES

       Upon successful completion, 0  is returned. Otherwise, -1 is returned and errno is set to indicate the error.

ERRORS

       The clock_settime(), clock_gettime() and clock_getres() functions will fail if:

       EINVAL	 The clock_id argument does not specify a known clock.

       ENOSYS	 The functions clock_settime(), clock_gettime(), and clock_getres() are not supported by this implementation.

       The clock_settime() function will fail if:

       EINVAL	 The tp argument to clock_settime() is outside the range for the given clock ID; or the tp argument specified a  nanosecond  value
		 less than zero or greater than or equal to 1000 million.

       The clock_settime() function may fail if:

       EPERM	The requesting process does not have the appropriate privilege to set the specified clock.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-------------------------------------+
       |ATTRIBUTE TYPE		     |ATTRIBUTE VALUE			   |
       +-----------------------------+-------------------------------------+
       |Interface Stability	     |Committed 			   |
       +-----------------------------+-------------------------------------+
       |MT-Level		     |clock_gettime() is Async-Signal-Safe |
       +-----------------------------+-------------------------------------+
       |Standard		     |See standards(5). 		   |
       +-----------------------------+-------------------------------------+

SEE ALSO

       time(2), ctime(3C), gethrtime(3C), time.h(3HEAD), timer_gettime(3C), attributes(5), standards(5)

SunOS 5.11							    5 Feb 2008							 clock_settime(3C)