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TIMEOUT(9) Kernel Developer's Manual TIMEOUT(9)

timeout_set, timeout_add, timeout_add_sec, timeout_add_msec, timeout_add_nsec, timeout_add_usec, timeout_add_tv, timeout_add_ts, timeout_add_bt, timeout_del, timeout_pending, timeout_initialized, timeout_triggeredexecute a function after a specified period of time

#include <sys/types.h>
#include <sys/timeout.h>

timeout_set(struct timeout *to, void (*fn)(void *), void *arg);

timeout_add(struct timeout *to, int ticks);

timeout_del(struct timeout *to);

timeout_pending(struct timeout *to);

timeout_initialized(struct timeout *to);

timeout_triggered(struct timeout *to);

timeout_add_tv(struct timeout *to, struct timeval *);

timeout_add_ts(struct timeout *to, struct timespec *);

timeout_add_bt(struct timeout *to, struct bintime *);

timeout_add_sec(struct timeout *to, int sec);

timeout_add_msec(struct timeout *to, int msec);

timeout_add_usec(struct timeout *to, int usec);

timeout_add_nsec(struct timeout *to, int nsec);

The timeout API provides a mechanism to execute a function at a given time. The granularity of the time is limited by the granularity of the hardclock(9) timer which executes hz(9) times a second. The function will be called at softclock interrupt level.

It is the responsibility of the caller to provide these functions with pre-allocated timeout structures. All functions in this API may be used in interrupt context below ().

The function () prepares the timeout structure to to be used in future calls to timeout_add() and timeout_del(). The timeout will be prepared to call the function specified by the fn argument with a void * argument given in the arg argument. Once initialized, the to structure can be used repeatedly in timeout_add() and timeout_del() and does not need to be reinitialized unless the function called and/or its argument must change.

The function () schedules the execution of the to timeout in at least ticks/hz seconds. Negative values of ticks are illegal. If the value is ‘0’ it will, in the current implementation, be treated as ‘1’, but in the future it might cause an immediate timeout. The timeout in the to argument must be already initialized by timeout_set() and may not be used in calls to timeout_set() until it has timed out or been removed with timeout_del(). If the timeout in the to argument is already scheduled, the old execution time will be replaced by the new one.

The function () will cancel the timeout in the argument to. If the timeout has already executed or has never been added the call will have no effect. If the timeout was actually removed by timeout_del() it will return 1.

The () macro can be used to check if a timeout is scheduled to run.

The () macro can be used to check if a timeout has been initialized.

The () macro can be used to check if a timeout is running or has been run. The timeout_add() and timeout_del() functions clear the triggered state for that timeout.

When possible, use the (), (), (), (), (), (), and () functions instead of timeout_add(). Those functions add a timeout whilst converting the time specified by the respective types.

These functions are implemented in the file sys/kern/kern_timeout.c.

hz(9), hzto(9), splclock(9), tsleep(9), tvtohz(9)

May 10, 2011 OpenBSD-5.1