1 .\" Copyright (c) 1980, 1991, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" Redistribution and use in source and binary forms, with or without
5 .\" modification, are permitted provided that the following conditions
7 .\" 1. Redistributions of source code must retain the above copyright
8 .\" notice, this list of conditions and the following disclaimer.
9 .\" 2. Redistributions in binary form must reproduce the above copyright
10 .\" notice, this list of conditions and the following disclaimer in the
11 .\" documentation and/or other materials provided with the distribution.
12 .\" 3. All advertising materials mentioning features or use of this software
13 .\" must display the following acknowledgement:
14 .\" This product includes software developed by the University of
15 .\" California, Berkeley and its contributors.
16 .\" 4. Neither the name of the University nor the names of its contributors
17 .\" may be used to endorse or promote products derived from this software
18 .\" without specific prior written permission.
20 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 .\" @(#)pipe.2 8.1 (Berkeley) 6/4/93
33 .\" $FreeBSD: src/lib/libc/sys/pipe.2,v 1.13.2.5 2001/12/14 18:34:01 ru Exp $
34 .\" $DragonFly: src/lib/libcr/sys/Attic/pipe.2,v 1.2 2003/06/17 04:26:47 dillon Exp $
41 .Nd create descriptor pair for interprocess communication
47 .Fn pipe "int *fildes"
54 which is an object allowing
55 bidirectional data flow,
56 and allocates a pair of file descriptors.
58 By convention, the first descriptor is normally used as the
61 and the second is normally the
63 so that data written to
65 appears on (i.e., can be read from)
67 This allows the output of one program to be
70 the source's standard output is set up to be
71 the write end of the pipe,
72 and the sink's standard input is set up to be
73 the read end of the pipe.
74 The pipe itself persists until all its associated descriptors are
77 A pipe that has had an end closed is considered
79 Writing on such a pipe causes the writing process to receive
83 Widowing a pipe is the only way to deliver end-of-file to a reader:
84 after the reader consumes any buffered data, reading a widowed pipe
87 The bidirectional nature of this implementation of pipes is not
88 portable to older systems, so it is recommended to use the convention
89 for using the endpoints in the traditional manner when using a
90 pipe in one direction.
99 Too many descriptors are active.
101 The system file table is full.
105 buffer is in an invalid area of the process's address
117 function call appeared in
120 Bidirectional pipes were first used on