CLOCK_NANOSLEEP(2) | Linux Programmer's Manual | CLOCK_NANOSLEEP(2) |
NAME
clock_nanosleep - high-resolution sleep with specifiable clockSYNOPSIS
#include <time.h>int clock_nanosleep(clockid_t clock_id , int flags ,
const struct timespec * request ,
struct timespec * remain );
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
DESCRIPTION
Like nanosleep(2), clock_nanosleep() allows the calling thread to sleep for an interval specified with nanosecond precision. It differs in allowing the caller to select the clock against which the sleep interval is to be measured, and in allowing the sleep interval to be specified as either an absolute or a relative value.struct timespec {
time_t tv_sec; /* seconds */
long tv_nsec; /* nanoseconds [0 .. 999999999] */
};
- CLOCK_REALTIME
- A settable system-wide real-time clock.
- CLOCK_MONOTONIC
- A nonsettable, monotonically increasing clock that measures time since some unspecified point in the past that does not change after system startup.
- CLOCK_PROCESS_CPUTIME_ID
- A settable per-process clock that measures CPU time consumed by all threads in the process.
See clock_getres(2) for further details on these clocks.
If flags is 0, then the value specified in request is interpreted as an interval relative to the current value of the clock specified by clock_id.
If flags is TIMER_ABSTIME, then request is interpreted as an absolute time as measured by the clock, clock_id. If request is less than or equal to the current value of the clock, then clock_nanosleep() returns immediately without suspending the calling thread.
clock_nanosleep() suspends the execution of the calling thread until either at least the time specified by request has elapsed, or a signal is delivered that causes a signal handler to be called or that terminates the process.
If the call is interrupted by a signal handler, clock_nanosleep() fails with the error EINTR. In addition, if remain is not NULL, and flags was not TIMER_ABSTIME, it returns the remaining unslept time in remain. This value can then be used to call clock_nanosleep() again and complete a (relative) sleep.
RETURN VALUE
On successfully sleeping for the requested interval, clock_nanosleep() returns 0. If the call is interrupted by a signal handler or encounters an error, then it returns one of the positive error number listed in ERRORS.ERRORS
- EFAULT
- request or remain specified an invalid address.
- EINTR
- The sleep was interrupted by a signal handler.
- EINVAL
- The value in the tv_nsec field was not in the range 0 to 999999999 or tv_sec was negative.
- EINVAL
- clock_id was invalid. ( CLOCK_THREAD_CPUTIME_ID is not a permitted value for clock_id.)
VERSIONS
The clock_nanosleep() system call first appeared in Linux 2.6. Support is available in glibc since version 2.1.CONFORMING TO
POSIX.1-2001.NOTES
If the interval specified in request is not an exact multiple of the granularity underlying clock (see time(7)), then the interval will be rounded up to the next multiple. Furthermore, after the sleep completes, there may still be a delay before the CPU becomes free to once again execute the calling thread.SEE ALSO
clock_getres(2), nanosleep(2), restart_syscall(2), timer_create(2), sleep(3), usleep(3), time(7)COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.2013-07-30 | Linux |