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1.\" Copyright (c) 2004 Alex Vasylenko <lxv@omut.org>
2.\" All rights reserved.
3.\"
4.\" Redistribution and use in source and binary forms, with or without
5.\" modification, are permitted provided that the following conditions
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13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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25.\" Portions of this text are reprinted and reproduced in electronic form
26.\" from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology --
27.\" Portable Operating System Interface (POSIX), The Open Group Base
28.\" Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of
29.\" Electrical and Electronics Engineers, Inc and The Open Group. In the
30.\" event of any discrepancy between this version and the original IEEE and
31.\" The Open Group Standard, the original IEEE and The Open Group Standard is
32.\" the referee document. The original Standard can be obtained online at
33.\" http://www.opengroup.org/unix/online.html.
34.\"
35.\" $FreeBSD: src/share/man/man3/pthread_atfork.3,v 1.3 2005/06/16 18:46:16 ru Exp $
36.\"
37.Dd July 10, 2009
38.Dt PTHREAD_ATFORK 3
39.Os
40.Sh NAME
41.Nm pthread_atfork
42.Nd register fork handlers
43.Sh LIBRARY
44.Lb libpthread
45.Sh SYNOPSIS
46.In pthread.h
47.Ft int
48.Fo pthread_atfork
49.Fa "void \*[lp]*prepare\*[rp]\*[lp]void\*[rp]"
50.Fa "void \*[lp]*parent\*[rp]\*[lp]void\*[rp]"
51.Fa "void \*[lp]*child\*[rp]\*[lp]void\*[rp]"
52.Fc
53.Sh DESCRIPTION
54The
55.Fn pthread_atfork
56function declares fork handlers to be called before and after
57.Xr fork 2 ,
58in the context of the thread that called
59.Xr fork 2 .
60.Pp
61The handlers registered with
62.Fn pthread_atfork
63are called at the moments in time described below:
64.Bl -tag -width ".Fa prepare"
65.It Fa prepare
66Before
67.Xr fork 2
68processing commences in the parent process.
69If more than one
70.Fa prepare
71handler is registered they will be called in the opposite order
72they were registered.
73.It Fa parent
74After
75.Xr fork 2
76completes in the parent process.
77If more than one
78.Fa parent
79handler is registered they will be called in the same order
80they were registered.
81.It Fa child
82After
83.Xr fork 2
84processing completes in the child process.
85If more than one
86.Fa child
87handler is registered they will be called in the same order
88they were registered.
89.El
90.Pp
91If no handling is desired at one or more of these three points,
92a null pointer may be passed as the corresponding fork handler.
93.Sh RETURN VALUES
94If successful, the
95.Fn pthread_atfork
96function will return zero.
97Otherwise an error number will be returned to indicate the error.
98.Sh ERRORS
99The
100.Fn pthread_atfork
101function will fail if:
102.Bl -tag -width Er
103.It Bq Er ENOMEM
104Insufficient table space exists to record the fork handler addresses.
105.El
106.Sh SEE ALSO
107.Xr fork 2 ,
108.Xr pthread 3
109.Sh STANDARDS
110The
111.Fn pthread_atfork
112function is expected to conform to
113.St -p1003.1 .
114.Sh AUTHORS
115This manpage was written by
116.An Alex Vasylenko
117.Aq lxv@omut.org .