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TIMER_SETTIME(2)              System Calls Manual             TIMER_SETTIME(2)

NAME
     timer_settime, timer_gettime, timer_getoverrun - process timer
     manipulation

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <time.h>

     int
     timer_settime(timer_t timerid, int flags,
         const struct itimerspec * restrict tim,
         struct itimerspec * restrict otim);

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

     int
     timer_getoverrun(timer_t timerid);

DESCRIPTION
     The timer_settime() sets the next expiration time of the timer with ID
     timerid to the it_value (see itimerspec(3)) specified in the tim
     argument.  If the value is 0, the timer is disarmed.  If the argument
     otim is not NULL the old timer settings are returned.

     If the flags argument is set to TIMER_RELTIME then the expiration time is
     set to the value in nanoseconds specified in the tim argument from the
     time the call to timer_settime() was made.  If the flags argument is set
     to TIMER_ABSTIME then the expiration time is set to be equal to the
     difference between the clock associated with this timer, and the value
     specified in the tim argument.  If that time has already passed, then the
     call succeeds, and the expiration notification occurs.

     If the it_interval of the tim argument is non-zero, then the timer
     reloads upon expiration.

     The timer_gettime() function returns the current settings of the timer
     specified by the timerid argument in the tim argument.

     Only one notification event (signal) can be pending for a given timer and
     process.  If a timer expires while the signal is still queued for
     delivery, then the overrun counter for that timer is increased.  The
     counter can store values up to DELAYTIMER_MAX.  When the signal is
     finally delivered to the process, then the timer_getoverrun() function
     can be used to retrieve the overrun counter for the timer specified in
     the timerid argument.

NOTES
     Expiration time values are always rounded up to the resolution of the
     timer, so a notification will never be sent before the requested time.
     Values returned in the otim argument of timer_settime() or in the tim
     argument of timer_gettime() are subject to the above rounding effect and
     might not exactly match the requested values by the user.

RETURN VALUES
     If successful, the timer_gettime() and timer_settime() functions return
     0, and the timer_getoverrun() function returns the expiration overrun
     count for the specified timer.  Otherwise, the functions return -1, and
     set errno to indicate the error.

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

     [EINVAL]           The argument timerid does not correspond to a valid
                        timer id as returned by timer_create() or that timer
                        id has been deleted by timer_delete().

     The timer_settime() function will fail if:

     [EINVAL]           A nanosecond field in the tim structure specified a
                        value less than zero or greater than or equal to 10^9.

SEE ALSO
     clock_gettime(2), timer_create(2), timer_delete(2)

STANDARDS
     IEEE Std 1003.1b-1993 ("POSIX.1b"), IEEE Std 1003.1i-1995 ("POSIX.1i")

NetBSD 10.99                     May 17, 2010                     NetBSD 10.99