NAME
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_triggered —
execute a function after a specified
period of time
SYNOPSIS
#include
<sys/types.h>
#include <sys/timeout.h>
void
timeout_set(struct
timeout *to, void
(*fn)(void *), void
*arg);
int
timeout_add(struct
timeout *to, int
ticks);
int
timeout_del(struct
timeout *to);
int
timeout_pending(struct
timeout *to);
int
timeout_initialized(struct
timeout *to);
int
timeout_triggered(struct
timeout *to);
int
timeout_add_tv(struct
timeout *to, struct
timeval *);
int
timeout_add_ts(struct
timeout *to, struct
timespec *);
int
timeout_add_bt(struct
timeout *to, struct
bintime *);
int
timeout_add_sec(struct
timeout *to, int
sec);
int
timeout_add_msec(struct
timeout *to, int
msec);
int
timeout_add_usec(struct
timeout *to, int
usec);
int
timeout_add_nsec(struct
timeout *to, int
nsec);
DESCRIPTION
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.
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 running or has been run. The
timeout_add() and
timeout_del() functions clear the triggered state
for that timeout.
When possible, use the
timeout_add_tv(),
timeout_add_ts(),
timeout_add_bt(),
timeout_add_sec(),
timeout_add_msec(),
timeout_add_usec(),
and
timeout_add_nsec()
functions instead of timeout_add(). Those functions
add a timeout whilst converting the time specified by the respective
types.
CONTEXT
timeout_set() can be called during
autoconf, from process context, or from interrupt context.
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_triggered() can be called during autoconf,
from process context, or from any interrupt context at or below
IPL_CLOCK.
RETURN VALUES
timeout_add(),
timeout_add_sec(),
timeout_add_msec(),
timeout_add_nsec(),
timeout_add_usec(),
timeout_add_tv(),
timeout_add_ts(), and
timeout_add_bt() will return 1 if the timeout
to was added to the timeout schedule or 0 if it was
already queued.
timeout_del() will return 1 if the timeout
to was removed from the pending timeout schedule or 0
if it was not currently queued.
CODE REFERENCES
These functions are implemented in the file sys/kern/kern_timeout.c.