dtk_nanosleep(3) [debian man page]

DTK_NANOSLEEP(3)						Draw Toolkit manual						  DTK_NANOSLEEP(3)

NAME

       dtk_nanosleep - high-resolution sleep

SYNOPSIS

       #include <dtk_time.h>

       int dtk_nanosleep(int abs, const struct dtk_timespec* req,
				  struct dtk_timespec* rem);

DESCRIPTION

       The  function dtk_nanosleep() allows the caller to sleep for an interval with nanosecond precision. If the argument abs is zero, the speci-
       fied interval is interpretated as a relative value, otherwise an absolute value. The interval is specified by the req argument which  is  a
       pointer to a dtk_timespec structure defined as:

	   struct dtk_timespec {
	       long sec;    /* seconds */
	       long nsec;   /* nanoseconds */
	   };

       If interpreted as an absolute value, it represents seconds and nanoseconds since the Epoch, 1970-01-01 00:00:00 +0000  (UTC).

       dtk_nanosleep()	suspends  the  execution of the calling thread until either at least the time specified by req 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, dtk_nanosleep() returns -1, and sets errno to EINTR. In addition, if rem is not	NULL,  and
       abs  is zero, it returns the remaining unslept time in rem. This value can then be used to call dtk_nanosleep() again and complete a (rela-
       tive) sleep.

RETURN VALUE

       On successfully sleeping for the requested interval, dtk_nanosleep() returns 0. If the call is interrupted by a signal handler  or  encoun-
       ters an error, then it returns -1 and errno is set appropriately.

ERRORS

       dtk_nanosleep() will fail if:

       EINTR  The sleep was interrupted by a signal handler.

       EINVAL The value in the nsec field was not in the range 0 to 999999999 or sec was negative.

NOTE

       This  function is a wrapper to clock_nanosleep(2) if it is provided by the system. Otherwise, it implements the function by using the sleep
       function with the highest precision available on the system.

SEE ALSO

       dtk_nanosleep(3), clock_nanosleep(2)

EPFL
								       2011							  DTK_NANOSLEEP(3)

NANOSLEEP(2)						     Linux Programmer's Manual						      NANOSLEEP(2)

NAME

       nanosleep - pause execution for a specified time

SYNOPSIS

       #include <time.h>

       int nanosleep(const struct timespec *req, struct timespec *rem);

DESCRIPTION

       nanosleep  delays  the  execution  of the program for at least the time specified in *req.  The function can return earlier if a signal has
       been delivered to the process. In this case, it returns -1, sets errno to EINTR, and writes the remaining time into the	structure  pointed
       to by rem unless rem is NULL.  The value of *rem can then be used to call nanosleep again and complete the specified pause.

       The structure timespec is used to specify intervals of time with nanosecond precision. It is specified in <time.h> and has the form

	      struct timespec
	      {
		      time_t  tv_sec;	      /* seconds */
		      long    tv_nsec;	      /* nanoseconds */
	      };

       The value of the nanoseconds field must be in the range 0 to 999 999 999.

       Compared  to  sleep(3)  and  usleep(3),	nanosleep has the advantage of not affecting any signals, it is standardized by POSIX, it provides
       higher timing resolution, and it allows to continue a sleep that has been interrupted by a signal more easily.

ERRORS

       In case of an error or exception, the nanosleep system call returns -1 instead of 0 and sets errno to one of the following values:

       EINTR  The pause has been interrupted by a non-blocked signal that was delivered to the process. The remaining sleep time has been  written
	      into *rem so that the process can easily call nanosleep again and continue with the pause.

       EINVAL The value in the tv_nsec field was not in the range 0 to 999 999 999 or tv_sec was negative.

BUGS

       The  current  implementation  of  nanosleep  is based on the normal kernel timer mechanism, which has a resolution of 1/HZ s (i.e, 10 ms on
       Linux/i386 and 1 ms on Linux/Alpha).  Therefore, nanosleep pauses always for at least the specified time, however it can take up to  10	ms
       longer  than  specified	until the process becomes runnable again. For the same reason, the value returned in case of a delivered signal in
       *rem is usually rounded to the next larger multiple of 1/HZ s.

       As some applications require much more precise pauses (e.g., in order to control some time-critical hardware), nanosleep is also capable of
       short  high-precision  pauses.  If the process is scheduled under a real-time policy like SCHED_FIFO or SCHED_RR, then pauses of up to 2 ms
       will be performed as busy waits with microsecond precision.

CONFORMING TO

       POSIX.1b (formerly POSIX.4).

SEE ALSO

       sleep(3), usleep(3), sched_setscheduler(2), timer_create(2)

Linux 1.3.85							    1996-04-10							      NANOSLEEP(2)