freebsd-dev/share/man/man9/at_shutdown.9

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.\"
.\" Copyright (c) 1996 Julian Elischer
.\"
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" $Id: at_shutdown.9,v 1.1 1996/04/13 16:59:07 joerg Exp $
.\" "
.Dd August 15, 1996
.Os
.Dt AT_SHUTDOWN 9
.Sh NAME
.Nm at_shutdown ,
.Nm rm_at_shutdown
.Nd ask that a function be run at shutdown.
.Sh SYNOPSIS
.Fd #include <sys/systm.h>
.Fd #include <sys/reboot.h>
.Ft typedef void \*(lp*bootlist_fn\*(rp \*(lpint, void *\*(rp;
.Ft void
.Fn at_shutdown "bootlist_fn func" "void *arg"
.Ft void
.Fn rm_at_shutdown "bootlist_fn func" "void *arg"
.Sh DESCRIPTION
The
.Nm at_shutdown
facility allows a kernel module to ensure that it is notified
at system shutdown.
The function
.Ar func
is called with the flags indicating boot type, and the opaque argument
.Ar arg
when the system is shut down
.Pp
If the requirement for notification is removed, then the function
.Nm rm_at_shutdown
must be called with the exact
.Ar func
and
.Ar arg
arguments as the corresponding call to
.Fn at_shutdown .
.Pp
.Sh RETURN VALUES
.Nm at_shutdown
returns an errno, 0 meaning success.
.Nm rm_at_shutdown
returns the number of items removed (should be 0 or 1).
.Sh SEE ALSO
.Xr reboot 2
.Sh HISTORY
The
.Nm at_shutdown
appeared in FreeBSD 2.2
.Sh BUGS
Since the shutdown queue is not sorted
and items are added to the head, order of execution
is reversed to that of insertion.
.Sh AUTHORS
The function was written by
.ie t Julian Elischer (julian@freebsd.org)
.el Julian Elischer (julian@freebsd.org)