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

Check Out this Related Man Page

clock_gettime(3)					     Library Functions Manual						  clock_gettime(3)

NAME

       clock_gettime, clock_settime - Obtains or sets the time for the specified clock (P1003.1b)

LIBRARY

       Realtime Library (librt.so, librt.a)

SYNOPSIS

       #include <time.h>

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

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

PARAMETERS

       clock_id    The	clock  type  used  to  obtain the time for the clock that is set. The CLOCK_REALTIME clock is supported and represents the
		   TIME-OF-DAY clock for the system.

       *tp	   A pointer to a timespec data structure.

DESCRIPTION

       The clock_gettime function returns the current time (in seconds and nanoseconds) for the specified clock.  The clock_settime function  sets
       the  specified  clock.  The  CLOCK_REALTIME clock measures the amount of time elapsed since 00:00:00:00 January 1, 1970 Greenwich Mean Time
       (GMT), otherwise known as the Epoch. Time values  that fall between two non-negative integer multiples of the resolution are truncated down
       to the smaller multiple of the resolution.

       You must have superuser privileges to use the clock_settime function.

RETURN VALUES

       On a successful call to the clock_gettime or clock_settime functions, a value of 0 (zero) is returned.

       On an unsuccessful call, a value of -1 is returned and errno is set to indicate that an error occurred.

ERRORS

       The clock_gettime and clock_settime functions fail under the following conditions:

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

		      The value pointed to by the tp argument to the clock_settime function is outside the range for the given clock_id.

		      The tp argument specified a nanosecond value less than zero or greater than or equal to 1000 million.

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

RELATED INFORMATION

       Functions: time(1), clock_getres(3), ctime(3), timer_gettime(3)

       Guide to Realtime Programming delim off

																  clock_gettime(3)

Linux and UNIX Man Pages

clock_getres(2) [netbsd man page]

Check Out this Related Man Page