1.\" 2.\" Copyright (c) 1996 Julian Elischer 3.\" 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.\" $FreeBSD: src/share/man/man9/at_fork.9,v 1.9.2.7 2002/01/10 09:36:27 ru Exp $ 27.\" 28.Dd August 15, 1996 29.Dt AT_FORK 9 30.Os 31.Sh NAME 32.Nm at_fork , 33.Nm rm_at_fork 34.Nd ask that a function be run at fork 35.Sh SYNOPSIS 36.In sys/types.h 37.In sys/systm.h 38.Ft "typedef void" 39.Fn (*forklist_fn) "struct proc *" "struct proc *" int 40.Pp 41.Ft int 42.Fn at_fork "forklist_fn func" 43.Ft int 44.Fn rm_at_fork "forklist_fn func" 45.Sh DESCRIPTION 46The 47.Nm 48facility allows a kernel module to ensure that it is notified 49at any process fork. 50The function 51.Fa func 52is called with the a pointer to the forking process's proc structure, 53a pointer to the child's process structure and a flag word, 54as used in 55.Xr rfork 2 56to indicate the type of fork. 57.Pp 58If the requirement for notification is removed, then the function 59.Fn rm_at_fork 60must be called with the exact 61.Fa func 62argument as the corresponding call to 63.Fn at_fork . 64.Sh RETURN VALUES 65.Fn at_fork 66returns an 67.Va errno , 680 meaning success. 69.Fn rm_at_fork 70returns the number of items removed (should be 0 or 1). 71.Sh SEE ALSO 72.Xr fork 2 73.Sh HISTORY 74The 75.Fn at_fork 76function appeared in 77.Fx 2.2 . 78.Sh AUTHORS 79The function was written by 80.An Julian Elischer Aq Mt julian@FreeBSD.org . 81