HP-UX Reference (11i v3 07/02) - 2 System Calls (vol 5)

n
nanosleep(2) nanosleep(2)
NAME
nanosleep() - high resolution sleep
SYNOPSIS
#include <time.h>
int nanosleep(
const struct timespec *rqtp,
struct timespec *rmtp
);
DESCRIPTION
The 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 to terminate the process. The suspension time may be
longer than that 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. However, with the exception of 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() function has no effect on the action or blockage of any signal.
RETURN VALUE
If the nanosleep() function returns because the requested time has elapsed, its return value is zero.
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 a value of −1 and sets errno to indicate the error.
ERRORS
If any of the following conditions occur, the
nanosleep() function returns −1 and sets errno (see
errno(2)) to the corresponding value:
[EFAULT] The
rqtp or rmtp arguments specify an invalid address.
[EINTR]
nanosleep() 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 function nanosleep() is not supported by this implementation.
EXAMPLES
Suspend execution of the current thread for half a second:
#include <time.h>
#include <errno.h>
struct timespec interval, remainder;
interval.tv_sec = 0;
interval.tv_nsec = 500000000;
if (nanosleep(&interval, &remainder) == -1) {
if (errno == EINTR) {
(void)printf("nanosleep interrupted\n");
(void)printf("Remaining secs: %d\n", remainder.tv_sec);
(void)printf("Remaining nsecs: %d\n", remainder.tv_nsec);
}
else perror("nanosleep");
}
AUTHOR
nanosleep was derived from the proposed IEEE POSIX P1003.4 Standard, Draft 14.
252 Hewlett-Packard Company − 1 − HP-UX 11i Version 3: February 2007