NAME

clock_settime, clock_gettime, clock_getres − high-resolution clock operations

SYNOPSIS

cc [ flag ... ] file ... −lposix4 [ library ... ]

#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);

struct  timespec {
time_ttv_sec;/∗ seconds ∗/
longtv_nsec;/∗ and nanoseconds ∗/
};

MT-LEVEL

clock_gettime() is Async-Signal-Safe

DESCRIPTION

clock_settime() sets the specified clock, clock_id, to the value specified by tp.  The calling process must have an effective user ID of 0. 

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

The resolution of any clock can be obtained by calling clock_getres(). If res is not NULL, the resolution of the specified clock is stored in res. 

The clock_id for the real-time clock for the system is CLOCK_REALTIME.  The values returned by clock_gettime() and specified by clock_settime() represent the amount of time (in seconds and nanoseconds) since 00:00 Universal Coordinated Time, January 1, 1970. 

RETURN VALUES

clock_settime(), clock_gettime(), and clock_getres() return 0 upon success, otherwise they return -1 and set errno to indicate the error condition. 

ERRORS

EINVAL clock_id does not specify a known clock. 
The tp argument to clock_settime() is outside the range for the given clock id. 
The tp argument to clock_settime() specified a nanosecond value less than zero or greater than or equal to 1,000,000,000. 

ENOSYS clock_settime(), clock_gettime(), or clock_getres() is not supported by this implementation. 

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

SEE ALSO

time(2), ctime(3C), timer_gettime(3R)

NOTES

Clock resolutions are implementation defined and are not settable by a process.  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. 

SunOS 5.5/SPARC  —  Last change: 27 Apr 1994