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timer_settime(3) Library Functions Manual timer_settime(3) NAME timer_settime, timer_gettime - Get or set the expiration time of the specified per-process timer (P1003.1b) SYNOPSIS #include <time.h> int timer_gettime ( timer_t timerid, struct itimerspec *value); int timer_settime ( timer_t timerid, int flags, const struct itimerspec *value, struct itimerspec *ovalue); PARAMETERS timerid The timer ID for the timer whose expiration time is set or re- turned. flags Specifies whether the timer is to be an absolute or relative timer. *value A pointer to an itimerspec data structure. *ovalue A pointer to the itimerspec data structure into which the time remaining on the previous timer is returned. DESCRIPTION The timer_gettime function returns the amount of time remaining in the current time interval before the expiration of the specified timer. The timer_settime function sets the expiration time of the specified per- process timer, determines whether the timer is an absolute or relative timer, returns the time remaining (if any) on the previous specified timer, and arms the timer. Both the timer_gettime and timer_settime functions use an itimerspec structure, which consists of the following members: struct timespec it_interval; struct timespec it_value; Each timespec structure consists of the following members: time_t tv_sec; long tv_nsec; Values specified for these members determine the duration of the timer intervals, as well as the start and end times. Use the timer_gettime function to determine whether a per-process timer is still active. If the timer is disabled, zero is returned. The timer_settime function sets the expiration time of the specified per-process timer and arms the timer. The TIMER_ABSTIME flag deter- mines whether the timer is an absolute or relative timer. If the TIMER_ABSTIME flag is not set (flags=0), the timer is set relative to the current time (a relative timer). In this case, the time until the next timer expiration equals the interval specified by the it_value member of value. The timer expires in the specified number of seconds and nanoseconds from when the call was made. If the TIMER_ABSTIME flag is set, the timer is set with a specified starting time (an absolute timer). In this case, the time until the next timer expiration equals the difference between the absolute time specified by the it_value member of value and the current value of the clock associated with the timer ID. The timer expires when the clock reaches the value specified by it_value member. Times that are between two consecutive non-negative integer multiples of the resolution are rounded up to the larger multiple of the resolu- tion. To disarm a timer, specify a value of zero for the it_value member and call the timer_settime function. The reload value to the timer is set to the value specified by the it_interval member of value. If the it_interval is zero, a one-shot timer is specified. If the it_interval is non-zero, a periodic timer is specified. RETURN VALUES On a successful call to the timer_gettime and timer_settime functions, a value of 0 is returned. On an unsuccessful call, a value of -1 is returned and errno is set to indicate that an error occurred. ERRORS The timer_gettime and timer_settime functions fail under the following conditions: [EINVAL] The timerid argument does not correspond to an id re- turned by timer_create, but not yet removed by timer_delete. The timer_settime function can fail with this error if a value structure specified a nanosecond value less than zero or greater than or equal to 1000 million. RELATED INFORMATION Functions: clock_gettime(3), timer_create(3) delim off timer_settime(3)