TIMEOUT(9) BSD Kernel Manual TIMEOUT(9)
timeout_set, timeout_add, timeout_del, timeout_pending,
timeout_initialized - execute a function after a specified period of time
#include <sys/types.h>
#include <sys/timeout.h>
void
timeout_set(struct timeout *to, void (*fn)(void *), void *arg);
void
timeout_add(struct timeout *to, int ticks);
void
timeout_del(struct timeout *to);
int
timeout_pending(struct timeout *to);
int
timeout_initialized(struct timeout *to);
int
timeout_triggered(struct timeout *to);
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 splclock().
This API replaces the historic functions timeout() and untimeout().
The function timeout_set() 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 timeout_add() 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 timeout_del() 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.
The timeout_pending() macro can be used to check if a timeout is
scheduled to run.
The timeout_initialized() macro can be used to check if a timeout has
been initialized.
The timeout_triggered() macro can be used to check if a timeout is run-
ning or has been run. The timeout_add() and timeout_del() functions clear
the triggered state for that timeout.
These functions are implemented in the file sys/kern/kern_timeout.c.
hz(9), hzto(9), sleep(9), splclock(9), tvtohz(9)
MirBSD #10-current June 23, 1996 1