CLOCK_NANOSLEEP(3C) Standard C Library Functions CLOCK_NANOSLEEP(3C)


NAME


clock_nanosleep - high resolution sleep with specifiable clock

SYNOPSIS


#include <time.h>

int clock_nanosleep(clockid_t clock_id, int flags,
const struct timespec *rqtp, struct timespec *rmtp);


DESCRIPTION


If the flag TIMER_ABSTIME is not set in the flags argument, the
clock_nanosleep() function causes the current thread to be suspended from
execution until either the time interval specified by the rqtp argument
has elapsed, or a signal is delivered to the calling thread and its
action is to invoke a signal-catching function, or the process is
terminated. The clock used to measure the time is the clock specified by
clock_id.


If the flag TIMER_ABSTIME is set in the flags argument, the
clock_nanosleep() function causes the current thread to be suspended from
execution until either the time value of the clock specified by clock_id
reaches the absolute time specified by the rqtp argument, or a signal is
delivered to the calling thread and its action is to invoke a signal-
catching function, or the process is terminated. If, at the time of the
call, the time value specified by rqtp is less than or equal to the time
value of the specified clock, then clock_nanosleep() returns immediately
and the calling process is not suspended.


The suspension time caused by this function can be longer than requested
because the argument value is rounded up to an integer multiple of the
sleep resolution, or because of the scheduling of other activity by the
system. But, except for the case of being interrupted by a signal, the
suspension time for the relative clock_nanosleep() function (that is,
with the TIMER_ABSTIME flag not set) will not be less than the time
interval specified by rqtp, as measured by the corresponding clock. The
suspension for the absolute clock_nanosleep() function (that is, with the
TIMER_ABSTIME flag set) will be in effect at least until the value of the
corresponding clock reaches the absolute time specified by rqtp, except
for the case of being interrupted by a signal.


The use of the clock_nanosleep() function has no effect on the action or
blockage of any signal.


The clock_nanosleep() function fails if the clock_id argument refers to
the CPU-time clock of the calling thread. It is unspecified if clock_id
values of other CPU-time clocks are allowed.

RETURN VALUES


If the clock_nanosleep() function returns because the requested time has
elapsed, its return value is 0.


If the clock_nanosleep() function returns because it has been interrupted
by a signal, it returns the corresponding error value. For the relative
clock_nanosleep() function, if the rmtp argument is non-null, the
timespec structure referenced by it is updated to contain the amount of
time remaining in the interval (the requested time minus the time
actually slept). If the rmtp argument is NULL, the remaining time is not
returned. The absolute clock_nanosleep() function has no effect on the
structure referenced by rmtp.


If clock_nanosleep() fails, it shall return the corresponding error
value.

ERRORS


The clock_nanosleep() function will fail if:

EINTR
The clock_nanosleep() function was interrupted by a signal.


EINVAL
The rqtp argument specified a nanosecond value less than zero
or greater than or equal to 1,000 million; or the
TIMER_ABSTIME flag was specified in flags and the rqtp
argument is outside the range for the clock specified by
clock_id; or the clock_id argument does not specify a known
clock, or specifies the CPU-time clock of the calling thread.


ENOTSUP
The clock_id argument specifies a clock for which
clock_nanosleep() is not supported, such as a CPU-time clock.


ATTRIBUTES


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


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

SEE ALSO


clock_getres(3C), nanosleep(3C), pthread_cond_timedwait(3C), sleep(3C),
attributes(5), standards(5)


February 5, 2008 CLOCK_NANOSLEEP(3C)