.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" This manpage is Copyright (C) 1992 Drew Eckhardt;
.\" and Copyright (C) 1993 Michael Haardt, Ian Jackson.
.\" and Copyright (C) 2005, 2008 Michael Kerrisk <mtk.manpages@gmail.com>
.\"
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.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
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.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
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.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
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.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
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.\" Modified 1993-07-21, Rik Faith <faith@cs.unc.edu>
.\" Modified 1994-08-21, Michael Chastain <mec@shell.portal.com>:
.\"   Fixed typoes.
.\" Modified 1997-01-31, Eric S. Raymond <esr@thyrsus.com>
.\" Modified 2002-09-28, aeb
.\" 2009-01-12, mtk, reordered text in DESCRIPTION and added some
.\"     details for dup2().
.\" 2008-10-09, mtk: add description of dup3()
.\"
.\" Japanese Version Copyright (c) 1996 Takeshi Ueno
.\"         all rights reserved.
.\" Translated 1996-07-03, Takeshi Ueno <tueno@vio.co.jp>
.\" Modified 1997-12-14, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Modified 2003-01-16, Akihiro Motoki <amotoki@dd.iij4u.or.jp>
.\" Updated & Modified 2004-05-19, Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated & Modified 2005-09-07 Akihiro MOTOKI
.\" Updated 2008-02-10, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v2.77
.\" Updated 2008-11-09, Akihiro MOTOKI, LDP v3.13
.\"
.TH DUP 2 2008-10-09 "Linux" "Linux Programmer's Manual"
.SH ̾
dup, dup2, dup3 \- ե롦ǥץʣ
.SH 
.nf
.B #include <unistd.h>
.sp
.BI "int dup(int " oldfd );
.BI "int dup2(int " oldfd ", int " newfd );
.sp
.B #define _GNU_SOURCE
.B #include <unistd.h>
.sp
.BI "int dup3(int " oldfd ", int " newfd ", int " flags );
.fi
.SH 
Υƥॳϡե롦ǥץ
.I oldfd
ʣ롣

.BR dup ()
ϺǤ⾮ֹ̤ѤΥǥץ
ǥץȤƻѤ롣

.BR dup2 ()

.I newfd

.I oldfd
ʣȤƺ롣
ɬפǤкǽ
.I newfd
򥯥롣
ʲդ뤳ȡ
.IP * 3
.I oldfd
ͭʥեǥץǤʤ硢θƤӽФϼԤ
.I newfd
ϥ롣
.IP *
.I oldfd
ͭʥեǥץǡ
.I newfd

.I oldfd
Ʊͤξ硢
.BR dup2 ()
ϲ⤻
.I newfd
֤
.PP
ΥƥॳΤ줫֤ˤϡ
Ťե롦ǥץȿե롦ǥץ
ߤ˲ĴʤΤȤƻȤȤǤ롣
2ĤΥե롦ǥץƱե뵭 (description)
.RB ( open (2)
) 򻲾ȤƤꡢäƥե륪եåȤե֥ե饰
ͭ롣㤨СΥǥץФ
.BR lseek (2)
Ȥäƥե륪եåȤѹ硢⤦Υǥץ
եåȤѲ롣

2ĤΥǥץϥե롦ǥץե饰 (close-on-exec flag)
ͭʤʣ줿ǥץ
close-on-exec flag
.RB ( fcntl (2)
)  off Ȥʤ롣

.BR dup3 ()

.BR dup2 ()
Ʊʲۤʤ롣
.IP * 3
ƤӽФե롦ǥץФ
close-on-exec ե饰Ūꤹ뤳ȤǤ롣
Ԥˤϡ
.I flags

.B O_CLOEXEC
ꤹ롣
Υե饰ΩͳˤĤƤϡ
.BR open (2)

.B O_CLOEXEC
ե饰򻲾ȤΤȡ
.IP *
.\" FIXME . To confirm with Al Viro that this was intended, and its rationale
.I oldfd

.I newfd
Ʊ硢
.BR dup3 ()

.B EINVAL
顼ǼԤ롣
.SH ֤
ȡΥƥॳϿǥץ֤
顼ξ硢\-1 ֤
.I errno
Ŭڤꤹ롣
.SH 顼
.TP
.B EBADF
.I oldfd
ץ󤵤줿ե롦ǥץǤʤ
.I newfd
ե롦ǥץȤƵϰϤ鳰Ƥ롣
.TP
.B EBUSY
(Linux Τ)
.BR open (2)

.BR dup ()
Ȥζ֤ξˡ
.BR dup2 ()

.BR dup3 ()
ϤΥ顼֤⤷ʤ
.TP
.B EINTR
.BR dup2 ()

.BR dup3 ()
θƤӽФʥˤޤ줿
.BR signal (7)
ȡ
.TP
.B EINVAL
.RB ( dup3 ())
.I flags
̵ͤäƤ롣
.\" FIXME . To confirm with Al Viro that this was intended, and its rationale
⤷ϡ
.I oldfd

.I newfd
ƱǤä
.TP
.B EMFILE
ץǤ˥ץǤޤǥե롦ǥץ
򳫤Ƥơ˿Τ򳫤Ȥ
.SH С
.BR dup3 ()
ϥС 2.6.27  Linux ɲä줿
glibc ˤ륵ݡȤϥС 2.9 ʹߤѤǤ롣
.SH 
.BR dup (),
.BR dup2 ():
SVr4, 4.3BSD, POSIX.1-2001.

.BR dup3 ()
 Linux ͭǤ롣
.\" SVr4 ˤ¾ EINTR, ENOLINK 顼֤εҤ롣
.\" POSIX.1 ˤ¾ EINTR 롣
.\" EBUSY ֤Τ Linux ȼΤΤǤ롣
.SH 
.I newfd
ϰϤĶ֤륨顼ϡ
.BR dup2 ()

.BR fcntl( "..., " F_DUPFD ", ..." )
ǤϰۤäƤ롣
.BR dup2 ()

.B F_DUPFD
Ʊ褦
.B EINVAL
֤ƥ⤢롣

.I newfd
ץ󤵤Ƥȡ
.BR close (2)
𤵤ϤΥ顼Ƥޤ
.BR dup2 ()

.BR dup3 ()
Ȥ褺
.I newfd
򥯥褦ˤ
.SH Ϣ
.BR close (2),
.BR fcntl (2),
.BR open (2)