This patch imports the unmodified current version of NetBSD libc. The NetBSD includes are in /nbsd_include, while the libc code itself is split between lib/nbsd_libc and common/lib/libc.
119 lines
3.6 KiB
Groff
119 lines
3.6 KiB
Groff
.\" $NetBSD: pipe.2,v 1.22 2004/05/13 10:20:58 wiz Exp $
|
|
.\"
|
|
.\" Copyright (c) 1980, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)pipe.2 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd July 17, 1994
|
|
.Dt PIPE 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm pipe
|
|
.Nd create descriptor pair for interprocess communication
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In unistd.h
|
|
.Ft int
|
|
.Fn pipe "int fildes[2]"
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn pipe
|
|
function
|
|
creates a
|
|
.Em pipe ,
|
|
which is an object allowing
|
|
unidirectional data flow,
|
|
and allocates a pair of file descriptors.
|
|
The first descriptor connects to the
|
|
.Em read end
|
|
of the pipe,
|
|
and the second connects to the
|
|
.Em write end ,
|
|
so that data written to
|
|
.Fa fildes[1]
|
|
appears on (i.e., can be read from)
|
|
.Fa fildes[0] .
|
|
This allows the output of one program to be
|
|
sent
|
|
to another program:
|
|
the source's standard output is set up to be
|
|
the write end of the pipe,
|
|
and the sink's standard input is set up to be
|
|
the read end of the pipe.
|
|
The pipe itself persists until all its associated descriptors are
|
|
closed.
|
|
.Pp
|
|
A pipe whose read or write end has been closed is considered
|
|
.Em widowed .
|
|
Writing on such a pipe causes the writing process to receive
|
|
a
|
|
.Dv SIGPIPE
|
|
signal.
|
|
Widowing a pipe is the only way to deliver end-of-file to a reader:
|
|
after the reader consumes any buffered data, reading a widowed pipe
|
|
returns a zero count.
|
|
.Sh RETURN VALUES
|
|
On successful creation of the pipe, zero is returned.
|
|
Otherwise, a value of \-1 is returned and the variable
|
|
.Va errno
|
|
set to indicate the
|
|
error.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn pipe
|
|
call will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EMFILE
|
|
Too many descriptors are active.
|
|
.It Bq Er ENFILE
|
|
The system file table is full.
|
|
.It Bq Er EFAULT
|
|
The
|
|
.Fa fildes
|
|
buffer is in an invalid area of the process's address space.
|
|
The reliable detection of this error cannot be guaranteed; when not
|
|
detected, a signal may be delivered to the process, indicating an
|
|
address violation.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr sh 1 ,
|
|
.Xr fork 2 ,
|
|
.Xr read 2 ,
|
|
.Xr socketpair 2 ,
|
|
.Xr write 2
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn pipe
|
|
function conforms to
|
|
.St -p1003.1-90 .
|
|
.Sh HISTORY
|
|
A
|
|
.Fn pipe
|
|
function call appeared in
|
|
.At v6 .
|