timer_settime(3C)					   Standard C Library Functions 					 timer_settime(3C)

NAME

       timer_settime, timer_gettime, timer_getoverrun - per-process timers

SYNOPSIS

       #include <time.h>

       int timer_settime(timer_t timerid, int flags,
	    const struct itimerspec *restrict value,
	    struct itimerspec *restrict ovalue);

       int timer_gettime(timer_t timerid, struct itimerspec *value);

       int timer_getoverrun(timer_t timerid);

DESCRIPTION

       The  timer_settime()  function  sets  the  time until the next expiration of the timer specified by timerid from the it_value member of the
       value argument and arm the timer if the it_value member of value is non-zero. If the specified timer was already armed when timer_settime()
       is  called, this call resets the time until next expiration to the value specified. If the it_value member of value is 0, the timer is dis-
       armed. The effect of disarming or resetting a timer on pending expiration notifications is unspecified.

       If the flag TIMER_ABSTIME is not set in the argument flags, timer_settime() behaves as if the time until next expiration is set to be equal
       to  the	interval specified by the it_value member of value. That is, the timer expires in it_value nanoseconds from when the call is made.
       If the flag TIMER_ABSTIME is set in the argument flags, timer_settime() behaves as if the time until next expiration is set to be equal	to
       the  difference	between  the  absolute	time  specified by the it_value member of value and the current value of the clock associated with
       timerid. That is, the timer expires when the clock reaches the value specified by the it_value member of value. If the specified  time  has
       already passed, the function succeeds and the expiration notification is made.

       The  reload  value  of  the  timer  is set to the value specified by the it_interval member of value. When a timer is armed with a non-zero
       it_interval, a periodic (or repetitive) timer is specified.

       Time values that are between two consecutive non-negative integer multiples of the resolution of the specified timer will be rounded up	to
       the larger multiple of the resolution. Quantization error will not cause the timer to expire earlier than the rounded time value.

       If  the	argument  ovalue  is not NULL, the function timer_settime() stores, in the location referenced by ovalue, a value representing the
       previous amount of time before the timer would have expired or 0 if the timer was disarmed, together with the previous timer reload  value.
       The  members of ovalue are subject to the resolution of the timer, and they are the same values that would be returned by a timer_gettime()
       call at that point in time.

       The timer_gettime() function stores the amount of time until the specified timer, timerid, expires and the reload value of the  timer  into
       the  space pointed to by the value argument. The it_value member of this structure contains the amount of time before the timer expires, or
       0 if the timer is disarmed. This value is returned as the interval until timer expiration, even if the timer was armed with absolute  time.
       The it_interval member of value contains the reload value last set by timer_settime().

       Only a single signal will be queued to the process for a given timer at any point in time. When a timer for which a signal is still pending
       expires, no signal will be queued, and a timer overrun occurs. When a timer expiration signal is delivered to or accepted by a process, the
       timer_getoverrun()  function  returns  the  timer expiration overrun count for the specified timer. The overrun count returned contains the
       number of extra timer expirations that occurred between the time the signal was generated (queued) and when it was delivered  or  accepted,
       up  to  but not including an implementation-dependent maximum of DELAYTIMER_MAX. If the number of such extra expirations is greater than or
       equal to DELAYTIMER_MAX, then the overrun count will be set to DELAYTIMER_MAX. The value returned by timer_getoverrun() applies to the most
       recent expiration signal delivery or acceptance for the timer. If no expiration signal has been delivered for the timer, the meaning of the
       overrun count returned is undefined.

RETURN VALUES

       If the timer_settime() or timer_gettime() functions succeed, 0 is returned. If an error	occurs	for  either  of  these	functions,  -1	is
       returned,  and  errno  is  set  to indicate the error. If the timer_getoverrun() function succeeds, it returns the timer expiration overrun
       count as explained above.

ERRORS

       The timer_settime(), timer_gettime() and timer_getoverrun() functions will fail if:

       EINVAL	  The timerid argument does not correspond to a timer returned by timer_create(3C) but not yet deleted by timer_delete(3C).

       ENOSYS	  The timer_settime(), timer_gettime(), and timer_getoverrun() functions are not supported  by	the  system.  The  timer_settime()
		  function will fail if:

       EINVAL	  A value structure specified a nanosecond value less than zero or greater than or equal to 1000 million.

ATTRIBUTES

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

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

SEE ALSO

       time.h(3HEAD), clock_settime(3C), timer_create(3C), timer_delete(3C), attributes(5), standards(5)

SunOS 5.11							    5 Feb 2008							 timer_settime(3C)