#include <time.h>

int nanosleep(const struct timespec *rqtp,
 struct timespec *rmtp);

#include <threads.h>

int thrd_sleep(const struct timespec *rqtp,
 struct timespec *rmtp);

 DESCRIPTION
The nanosleep() and thrd_sleep() functions cause 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 to terminate the
process. The suspension time may 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 will not be less than the
time specified by rqtp, as measured by the system clock,
CLOCK_REALTIME.

The use of the nanosleep() and thrd_sleep() functions has no effect
on the action or blockage of any signal.
 RETURN VALUES
If the nanosleep() or thrd_sleep() function returns because the
requested time has elapsed, its return value is 0.

If the nanosleep() function returns because it has been interrupted by a
signal, the function returns a value of -1 and sets errno to indicate
the interruption. 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.

If nanosleep() fails, it returns -1 and sets errno to
indicate the error.

The
 thrd_sleep() function may fail for identical reasons as the
 nanosleep() function and returns -1; however, the C11 standard does not define that
 errno should be set, therefore callers of thrd_sleep() cannot rely on
 errno being set or staying the same across a call to
 thrd_sleep() . 
 ERRORS
The nanosleep() function will fail if:
EINTR

The nanosleep() function was interrupted by a signal.


EINVAL

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


ENOSYS

The nanosleep() function is not supported by this implementation.


 ATTRIBUTES
See attributes(7) for descriptions of the following attributes:




ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Committed
MT-Level MT-Safe
Standard See standards(7).


 SEE ALSO
 sleep (3C),  time.h (3HEAD),  attributes (7),  standards (7)