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30 .\" @(#)pipe.2 8.1 (Berkeley) 6/4/93
37 .Nd create descriptor pair for interprocess communication
43 .Fn pipe "int fildes[2]"
45 .Fn pipe2 "int fildes[2]" "int flags"
52 which is an object allowing
53 unidirectional data flow,
54 and allocates a pair of file descriptors.
55 The first descriptor connects to the
58 and the second connects to the
60 so that data written to
62 appears on (i.e., can be read from)
64 This allows the output of one program to be
67 the source's standard output is set up to be
68 the write end of the pipe,
69 and the sink's standard input is set up to be
70 the read end of the pipe.
71 The pipe itself persists until all its associated descriptors are
74 A pipe whose read or write end has been closed is considered
76 Writing on such a pipe causes the writing process to receive
80 Widowing a pipe is the only way to deliver end-of-file to a reader:
81 after the reader consumes any buffered data, reading a widowed pipe
91 to be set on the returned file descriptor.
92 The following flags are valid:
93 .Bl -tag -width O_NONBLOCK -offset indent
99 Sets non-blocking I/O.
107 On successful creation of the pipe, zero is returned.
108 Otherwise, a value of \-1 is returned and the variable
122 buffer is in an invalid area of the process's address space.
123 The reliable detection of this error cannot be guaranteed; when not
124 detected, a signal may be delivered to the process, indicating an
127 Too many descriptors are active.
129 The system file table is full.
157 function call appeared in
161 function is inspired from Linux and appeared in