V10/man/man2/pipe.2

.TH PIPE 2
.CT 2 comm_proc
.SH NAME
pipe \(mi create an interprocess channel
.SH SYNOPSIS
.nf
.B int pipe(fildes)
.B int fildes[2];
.fi
.SH DESCRIPTION
.I Pipe
creates a buffered channel for interprocess I/O communication.
Two file descriptors returned in
.I fildes
are the ends of pair of cross-connected streams;
see
.IR stream (4).
Data written via
.B fildes[1]
is available for reading via
.B fildes[0]
and vice versa.
.PP
After the pipe has been set up,
cooperating processes
created by subsequent
.IR fork (2)
calls may pass data through the
pipe with
.I read
and
.I write
calls.
The bytes placed on a pipe
by one 
.I write
are contiguous even if many process are writing.
.I Writes
induce a record structure: a
.I read
will not return bytes from more than one 
.IR write ;
see
.IR read (2).
.PP
Write calls on a one-ended pipe raise signal
.BR SIGPIPE .
Read calls on a one-ended pipe with no data in it
return an end-of-file for the first several attempts, then raise
.BR SIGPIPE ,
and eventually
.BR SIGKILL .
.SH "SEE ALSO"
.IR sh (1), 
.IR fork (2),
.IR read (2),
.IR select (2),
.IR stream (4)
.SH DIAGNOSTICS
.BR EIO ,
.BR EMFILE ,
.BR ENFILE ,
.BR ENXIO
.SH BUGS
Buffering in pipes connecting multiple processes may cause deadlocks.
.PP
Some line discipline modules
discard the record delimiters
inserted by
.IR write .
.PP
On many other versions of the system,
only
.B fildes[0]
may be read
and only
.B fildes[1]
may be written.