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.\" $DragonFly: src/share/man/man9/at_fork.9,v 1.3 2007/06/30 19:03:52 swildner Exp $ 28.\" " 29.Dd August 15, 1996 30.Os 31.Dt AT_FORK 9 32.Sh NAME 33.Nm at_fork , 34.Nm rm_at_fork 35.Nd ask that a function be run at fork 36.Sh SYNOPSIS 37.In sys/types.h 38.In sys/systm.h 39.Ft "typedef void" 40.Fn \*[lp]*forklist_fn\*[rp] "struct proc *" "struct proc *" int 41.Pp 42.Ft int 43.Fn at_fork "forklist_fn func" 44.Ft int 45.Fn rm_at_fork "forklist_fn func" 46.Sh DESCRIPTION 47The 48.Nm 49facility allows a kernel module to ensure that it is notified 50at any process fork. 51The function 52.Fa func 53is called with the a pointer to the forking process's proc structure, 54a pointer to the child's process structure and a flag word, 55as used in 56.Xr rfork 2 57to indicate the type of fork. 58.Pp 59If the requirement for notification is removed, then the function 60.Fn rm_at_fork 61must be called with the exact 62.Fa func 63argument as the corresponding call to 64.Fn at_fork . 65.Sh RETURN VALUES 66.Fn at_fork 67returns an 68.Va errno , 690 meaning success. 70.Fn rm_at_fork 71returns the number of items removed (should be 0 or 1). 72.Sh SEE ALSO 73.Xr fork 2 74.Sh HISTORY 75The 76.Fn at_fork 77function appeared in 78.Fx 2.2 . 79.Sh AUTHORS 80The function was written by 81.An Julian Elischer Aq julian@FreeBSD.org . 82