xref: /freebsd/share/man/man3/pthread_atfork.3 (revision 6137b5f7b8c183ee8806d79b3f1d8e5e3ddb3df3)
1.\" Copyright (c) 2004 Alex Vasylenko <lxv@omut.org>
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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
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34.\"
35.Dd June 21, 2004
36.Dt PTHREAD_ATFORK 3
37.Os
38.Sh NAME
39.Nm pthread_atfork
40.Nd register fork handlers
41.Sh LIBRARY
42.Lb libpthread
43.Sh SYNOPSIS
44.In pthread.h
45.Ft int
46.Fo pthread_atfork
47.Fa "void \*[lp]*prepare\*[rp]\*[lp]void\*[rp]"
48.Fa "void \*[lp]*parent\*[rp]\*[lp]void\*[rp]"
49.Fa "void \*[lp]*child\*[rp]\*[lp]void\*[rp]"
50.Fc
51.Sh DESCRIPTION
52The
53.Fn pthread_atfork
54function declares fork handlers to be called before and after
55.Xr fork 2 ,
56in the context of the thread that called
57.Xr fork 2 .
58.Pp
59The handlers registered with
60.Fn pthread_atfork
61are called at the moments in time described below:
62.Bl -tag -width ".Fa prepare"
63.It Fa prepare
64Before
65.Xr fork 2
66processing commences in the parent process.
67If more than one
68.Fa prepare
69handler is registered they will be called in the opposite order
70they were registered.
71.It Fa parent
72After
73.Xr fork 2
74completes in the parent process.
75If more than one
76.Fa parent
77handler is registered they will be called in the same order
78they were registered.
79.It Fa child
80After
81.Xr fork 2
82processing completes in the child process.
83If more than one
84.Fa child
85handler is registered they will be called in the same order
86they were registered.
87.El
88.Pp
89If no handling is desired at one or more of these three points,
90a null pointer may be passed as the corresponding fork handler.
91.Sh RETURN VALUES
92If successful, the
93.Fn pthread_atfork
94function will return zero.
95Otherwise an error number will be returned to indicate the error.
96.Sh ERRORS
97The
98.Fn pthread_atfork
99function will fail if:
100.Bl -tag -width Er
101.It Bq Er ENOMEM
102Insufficient table space exists to record the fork handler addresses.
103.El
104.Sh SEE ALSO
105.Xr fork 2 ,
106.Xr pthread 3
107.Sh STANDARDS
108The
109.Fn pthread_atfork
110function is expected to conform to
111.St -p1003.1 .
112.Sh AUTHORS
113This manpage was written by
114.An Alex Vasylenko Aq Mt lxv@omut.org .
115