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1.\"-
2.\" Copyright (c) 2007 Dag-Erling Co�dan Sm�rgrav
3.\" All rights reserved.
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
7.\" are met:
8.\" 1. Redistributions of source code must retain the above copyright
9.\" notice, this list of conditions and the following disclaimer.
10.\" 2. Redistributions in binary form must reproduce the above copyright
11.\" notice, this list of conditions and the following disclaimer in the
12.\" documentation and/or other materials provided with the distribution.
13.\"
14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24.\" SUCH DAMAGE.
25.\"
26.\" $FreeBSD: head/lib/libutil/flopen.3 169446 2007-05-10 14:43:31Z des $
27.\"
28.Dd May 10, 2007
29.Dt FLOPEN 3
30.Os
31.Sh NAME
32.Nm flopen
33.Nd "Reliably open and lock a file"
34.Sh LIBRARY
35.Lb libutil
36.Sh SYNOPSIS
37.In sys/fcntl.h
38.In libutil.h
39.Ft int
40.Fn flopen "const char *path" "int flags"
41.Ft int
42.Fn flopen "const char *path" "int flags" "mode_t mode"
43.Sh DESCRIPTION
44The
45.Fn flopen
46function opens or creates a file and acquires an exclusive lock on it.
47It is essentially equivalent with calling
48.Fn open
49with the same parameters followed by
50.Fn flock
51with an
52.Va operation
53argument of
54.Dv LOCK_EX ,
55except that
56.Fn flopen
57will attempt to detect and handle races that may occur between opening
58/ creating the file and locking it.
59Thus, it is well suited for opening lock files, PID files, spool
60files, mailboxes and other kinds of files which are used for
61synchronization between processes.
62.Pp
63As with
64.Fn flopen ,
65the additional
66.Va mode
67argument is required if
68.Va flags
69includes
70.Dv O_CREAT .
71.Sh SEE ALSO
72.Xr flock 2 ,
73.Xr open 2
74.Sh AUTHORS
75.An -nosplit
76The
77.Nm
78function and this manual page were written by
79.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org .