.\"
.\" Copyright (c) 1996 Julian Elischer
.\"
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.\" $Id: at_exit.9,v 1.6 1997/02/22 13:26:21 peter Exp $
.\" "
.Dd August 15, 1996
.Os
.Dt AT_EXIT 9
.Sh NAME
.Nm at_exit ,
.Nm rm_at_exit
.Nd ask that a function be run at exit.
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/systm.h>
.Ft typedef void \*(lp*exitlist_fn\*(rp \*(lpstruct proc *\*(rp;

.Ft int
.Fn at_exit "exitlist_fn func"
.Ft int
.Fn rm_at_exit "exitlist_fn func"
.Sh DESCRIPTION
The
.Nm at_exit
facility allows a kernel module to ensure that it is notified
at any process exit.
The function
.Fa func
is called with the a pointer to the exiting process's proc structure.
.Pp
If the requirement for notification is removed, then the function 
.Fn rm_at_exit
must be called with the exact
.Fa func
argument as the corresponding call to
.Fn at_exit .
.Pp
.Sh RETURN VALUES
The
.Fa at_exit
function returns an errno, 0 meaning success.  The
.Fn rm_at_exit
function returns the number of items removed (should be 0 or 1).
.Sh SEE ALSO
.Xr _exit 2
.Sh HISTORY
The
.Fn at_exit
function appeared in
.Fx 2.2 .
.Sh BUGS
Since the exit 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 Julian Elischer  (julian@freebsd.org)
.el Julian Elischer  (julian@freebsd.org)