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28 .\" @(#)pipe.2 8.1 (Berkeley) 6/4/93
29 .\" $FreeBSD: src/lib/libc/sys/pipe.2,v 1.13.2.5 2001/12/14 18:34:01 ru Exp $
30 .\" $DragonFly: src/lib/libc/sys/pipe.2,v 1.2 2003/06/17 04:26:47 dillon Exp $
37 .Nd create descriptor pair for interprocess communication
43 .Fn pipe "int *fildes"
50 which is an object allowing
51 bidirectional data flow,
52 and allocates a pair of file descriptors.
54 By convention, the first descriptor is normally used as the
57 and the second is normally the
59 so that data written to
61 appears on (i.e., can be read from)
63 This allows the output of one program to be
66 the source's standard output is set up to be
67 the write end of the pipe,
68 and the sink's standard input is set up to be
69 the read end of the pipe.
70 The pipe itself persists until all its associated descriptors are
73 A pipe that has had an end closed is considered
75 Writing on such a pipe causes the writing process to receive
79 Widowing a pipe is the only way to deliver end-of-file to a reader:
80 after the reader consumes any buffered data, reading a widowed pipe
83 The bidirectional nature of this implementation of pipes is not
84 portable to older systems, so it is recommended to use the convention
85 for using the endpoints in the traditional manner when using a
86 pipe in one direction.
95 Too many descriptors are active.
97 The system file table is full.
101 buffer is in an invalid area of the process's address
113 function call appeared in
116 Bidirectional pipes were first used on