.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" This manpage is Copyright (C) 1992 Drew Eckhardt;
.\"                               1993 Michael Haardt, Ian Jackson.
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" 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.
.\" 
.\" 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.\" manual page may be incorrect or out-of-date.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
.\" professionally.
.\" 
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" Modified 1993-07-21 by Rik Faith <faith@cs.unc.edu>
.\" Modified 1994-08-21 by Michael Haardt
.\" Modified 1996-04-13 by Andries Brouwer <aeb@cwi.nl>
.\" Modified 1996-05-13 by Thomas Koenig
.\" Modified 1996-12-20 by Michael Haardt
.\" Modified 1999-02-19 by Andries Brouwer <aeb@cwi.nl>
.\" Modified 1998-11-28 by Joseph S. Myers <jsm28@hermes.cam.ac.uk>
.\" Modified 1999-06-03 by Michael Haardt
.\" Modified 2002-05-07 by Michael Kerrisk <mtk-manpages@gmx.net>
.\" Modified 2004-06-23 by Michael Kerrisk <mtk-manpages@gmx.net>
.\" 2004-12-08, mtk, reordered flags list alphabetically
.\" 2004-12-08, Martin Pool <mbp@sourcefrog.net> (& mtk), added O_NOATIME
.\"
.\" Japanese Version Copyright (c) 1997-1999 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated Sat Aug 14 10:17:47 JST 1999
.\"         by HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated Fri May 25 19:52:26 JST 2001
.\"         by Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated & Modified Wed Jan  2 15:41:02 JST 2002 by Yuichi SATO
.\" Updated & Modified Sun Jul  7 02:55:23 JST 2002 by Yuichi SATO
.\" Updated & Modified Thu Sep 19 04:20:18 JST 2002 by Yuichi SATO
.\" Updated & Modified Wed Jul 30 03:32:47 JST 2003 by Yuichi SATO
.\" Updated & Modified Thu Nov 27 01:02:55 JST 2003 by Yuichi SATO
.\" Updated & Modified Sat Jan  1 10:49:31 JST 2005 by Yuichi SATO
.\"
.\"WORD:	descriptor		ǥץ
.\"WORD:	open			ץ
.\"WORD:	create			
.\"WORD:	file offset		ե롦եå
.\"WORD:	controling terminal	ü
.\"WORD:	non-blocking I/O	 I/O
.\"WORD:	synchronous I/O		Ʊ I/O
.\"WORD:	permission		
.\"WORD:	user			桼
.\"WORD:	owner			ͭ
.\"WORD:	group			롼
.\"WORD:	other			¾
.\"WORD:	kernel			ͥ
.\"WORD:	symbolic link		ܥå
.\"WORD:	dangling symbolic link	줿ܥå
.\"
.TH OPEN 2 2004-12-08 "Linux 2.6.9" "Linux Programmer's Manual"
.SH ̾
open, creat \- եޤϥǥХΥץ󡢺Ԥ
.SH 
.nf
.B #include <sys/types.h>
.B #include <sys/stat.h>
.B #include <fcntl.h>
.sp
.BI "int open(const char *" pathname ", int " flags );
.BI "int open(const char *" pathname ", int " flags ", mode_t " mode );
.BI "int creat(const char *" pathname ", mode_t " mode );
.fi
.SH 
.B open
ƥॳϥե̾ե롦ǥץ (³
.BR read (2),
.BR write (2)
ʤ I/O ǻѤ뾮) ؤѴ˻Ѥ롣
ƤӽФ硢֤ե롦ǥץϡ
Υץλǥץ󤷤Ƥʤ
ե롦ǥץΤǾΤΤȤʤ롣
δؿϿ˥ץ󡦥ե (open file) 롣
ץ󡦥ե¾ΥץȶͭƤʤ
( 
.BR fork (2)
ƥॳǥץ󡦥ե뤬ͭ礬)
ե롦ǥץ exec ؿԤä open 줿
ޤޤǤ
.RB ( fcntl (2) 
򻲾)
ե롦եå (file offset) ϥեƬꤵ롣

ѥ᡼
.I flags

.BR O_RDONLY ", " O_WRONLY ", " O_RDWR
Τɤ줫ҤȤĤꤹ롣
줾ɤ߹ѡ񤭹ѡɤ߽Ѥ
ե򥪡ץ󤹤뤳Ȥ׵᤹롣
ޤ
.I flags
ˤϡʲΥե饰 (0 İʾ) ӥå OR (bitwise-or) ǻꤹ뤳ȤǤ롣
.TP
.B O_APPEND
եɲ (append) ⡼ɤǥץ󤹤롣

.BR write ()

.BR lseek ()
ԤäΤ褦ˡե롦ݥ󥿡եκǸ˰ư롣
NFS ե롦ƥǡ
.B O_APPEND
ѤȡʣΥץҤȤĤΥեƱ˥ǡɲä硢
ե뤬ƤޤȤ롣
 NFS ɲå⡼ɤ򥵥ݡȤƤʤᡢ
饤ȤΥͥ (kernel) 򥷥ߥ졼ȤʤФʤʤΤ
֤򤱤뤳ȤϤǤʤǤ롣
.TP
.B O_ASYNC
.\" ְ㤨Ƥ׽ -- 
.\" 䤬¤Ǥ open(2)  O_ASYNC ưʤ
.\" fcntl(2)  O_ASYNC ꤷȤΤư롣 -- MTK, Dec 04
Υե롦ǥץؤ
ϤޤϽϤǽˤʤäˡʥ
(ǥեȤ SIGIO Ǥ뤬
.BR fcntl (2)
ˤäѹǽǤ)
εǽϡüüåȤФƤΤ߻ѲǽǤ롣
˾ܤ
.BR fcntl (2)
򻲾Ȥ뤳ȡ
.TP
.B O_CREAT
ե뤬¸ߤʤäϺ (create) 롣
եνͭ (桼 ID) ϡץμ¸桼 ID ꤵ롣
롼׽ͭ (롼 ID) ϡץμ¸롼 ID
ޤϿƥǥ쥯ȥΥ롼 ID ꤵ
(ϡե륷ƥॿסޥȥץ
ƥǥ쥯ȥΥ⡼ɤ˰¸롣
㤨С
.BR mount (8)
Ƥ ext2 ե륷ƥΥޥȥץ
.I bsdgroups

.I sysvgroups
򸫤)
.TP
.B O_DIRECT
ΥեФ I/O Υåθ̤Ǿ褦Ȥ롣
Υե饰ȤȡŪǽ㲼롣
ץꥱȼ˥å󥰤ԤäƤ褦
̤ʾˤΩġ
ե I/O ϥ桼֥ХåեФľܹԤ롣
I/O ƱǹԤ롣
ʤ
.BR read (2)

.BR write (2)
ƥॳ뤬λǡǡžλȤݾڤ롣
Linux 2.4 Ǥϡž
桼ХåեΥ饤ȡե륪եåȤϡ
ե륷ƥ֥åܿǤʤФʤʤ
Linux 2.6 Ǥϡ512 ХȤȤζ֤ƤнʬǤ롣
.\" 饤ȤϲؤˤǥХɬ׾ʤФʤʤ
.\" ꤬¸ߤ뤫⤷ʤ
.br
֥åǥХФ̤ạ̈Υ󥿡ե
.BR raw (8)
Ƥ롣
.TP
.B O_DIRECTORY
\fIpathname\fR ǥ쥯ȥǤʤХץϼԤ롣
Υե饰 Linux ͭǤ롣
\fBopendir\fR(3)  FIFO ơץǥХФƥ뤵줿
ӥǽ (denial-of-service) 򤱤뤿
ͥ 2.1.126 ɲä줿
 \fBopendir\fR μʳǤϻѤ٤ǤϤʤ
.TP
.B O_EXCL
.B O_CREAT 
Ȱ˻Ѥ줿硢
ե뤬¸ߤϥ顼Ȥʤꡢ
.BR open ()
ϼԤ롣
ξ硢ܥå󥯤ǤäƤ¸ߤ뤦ꡢ
줬ɤؤƤ뤫ˤϤʤ
.B O_EXCL
 NFS ե롦ƥǤϵǽʤ
Υե饰ǥå (lock) ǽ¸ץϡ
ޤ
åեѤʬǽ (atomic) Υåǽβˤ
Ʊե롦ƥ¾̾νŤʤʤե
(㤨Хۥ̾ pid Ȥ߹碌) 
.BR link (2)
ѤƤΥåեؤΥ󥯤롣
\fBlink()\fP ֤ͤ 0 ʤХåƤ롣
뤤ϡΥե
.BR stat (2)
Ѥƥ󥯿 (link count)  2 ˤʤäƤ뤫å롣
ʤäƤСƱåƤȤȤǤ롣
.TP
.B O_LARGEFILE
(LFS)
.B off_t
Ǥϥɽʤ (
.B off64_t
Ǥϥɽ) ե򥪡ץǽˤ롣
.TP
.B O_NOATIME
(Linux 2.6.8 ʹ)
եФ
.BR read (2)
¹Ԥ줿Ȥˡǽ򹹿ʤ
Υե饰ϥǥåХååץץǻȤȤտޤƤ롣
ȤȥǥФ˸餹ȤǤ롣
Υե饰ƤΥե륷ƥФͭǤ櫓ǤϤʤ
ΰ㤬 NFS ǤꡢФƤ롣
.\" ְ㤨Ƥ׽? Υե饰 mmap()  readdir(2) ˤ
.\" st_atime ΰˤƶ롣MTK, Dec 04.
.TP
.B O_NOCTTY
.I pathname
ü (terminal) ǥХ
\(em 
.BR tty (4)

\(em
ؤƤˡȤΥץüäƤʤƤ⡢
ץ󤷤եüˤϤʤʤ
.TP
.B O_NOFOLLOW
\fIpathname\fR ܥå󥯤ä硢ץϼԤ롣
 FreeBSD γĥǡLinux ˤ 2.1.126 ɲä줿
pathname Υݡͥ (earlier component;
: ǸΥǥ쥯ȥꥻѥ졼ʬ) 
ܥå󥯤Ǥˤϡ줬ؤ褬Ȥ롣
glibc 2.0.100 ʹߤΥإåˤϤΥե饰롣
\fI2.1.126 ΥͥǻѤˤ̵뤵롣\fR
.TP
.BR O_NONBLOCK " ޤ " O_NDELAY
ǽʤСե (non-blocking) ⡼ɤǥץ󤵤롣
.BR open ()
⡢֤ե롦ǥץФʸΤ٤Ƥ
ƤӽФץԤ뤳ȤϤʤ
FIFO (͡ɡѥ) 򰷤ˤ
.BR fifo (4)
⻲Ȥ뤳ȡ
Υ⡼ɤ FIFO ʳΥեФƸ̤ɬפϤʤ
.TP
.B O_SYNC
եƱ (synchronous) I/O ⡼ɤǥץ󤵤롣
.BR open ()
֤ե롦ǥץФ
.BR write ()
ԤȡɬƤӽФץ֥å
ϡɥʪŪ˽񤭹ޤޤ֤ʤ
.I ʲΡ¡פ⸫衣
.TP
.B O_TRUNC
ե뤬¸ߤ̾եǤꡢ
񤭹߲ĥ⡼ɤǥץ󤵤Ƥ
(ĤޤꡢO_RDWR ޤ O_WRONLY ) 硢
Ĺ 0 ڤͤ (truncate) 롣
ե뤬 FIFO ޤüǥХեξ硢
O_TRUNC ե饰̵뤵롣
ʳξ硢O_TRUNC θ̤̤Ǥ롣
.PP
ե饰ΤĤϥե򥪡ץ󤷤Ǥ
.BR fcntl ()
Ѥѹ뤳ȤǤ롣


.I mode
Ͽե˻Ѥ륢 (permission) ꤹ롣
ϥץ 
.B umask
̤̾꽤졢줿եεĤ
.B "(mode & ~umask)" 
Ȥʤ롣
Υ⡼ɤϿ줿ե
ΥˤΤŬѤդ뤳ȡ
ɤ߼ѤΥե
.BR open ()
ǤäƤ⡢
ɤ߽񤭲ǽʥե롦ǥץ֤Ȥꤦ롣
.PP
.I mode 
Τ˰ʲΥܥ󶡤Ƥ :
.TP
.B S_IRWXU
00700 桼 (եνͭ) ɤ߹ߡ񤭹ߡ
¹ԤεĤ롣
.TP
.B S_IRUSR (S_IREAD)
00400 桼ˤɤ߹ߤεĤ롣
.TP
.B S_IWUSR (S_IWRITE)
00200 桼ˤϽ񤭹ߤεĤ롣
.TP
.B S_IXUSR (S_IEXEC)
00100 桼ˤϼ¹ԤεĤ롣
.TP
.B S_IRWXG
00070 롼פˤɤ߹ߡ񤭹ߡ¹ԤεĤ롣
.TP
.B S_IRGRP
00040 롼פˤɤ߹ߤεĤ롣
.TP
.B S_IWGRP
00020 롼פˤϽ񤭹ߤεĤ롣
.TP
.B S_IXGRP
00010 롼פˤϼ¹ԤεĤ롣
.TP
.B S_IRWXO
00007 ¾ (others) ɤ߹ߡ񤭹ߡ¹ԤεĤ롣
.TP
.B S_IROTH
00004 ¾ͤˤɤ߹ߤεĤ롣
.TP
.B S_IWOTH
00002 ¾ͤˤϽ񤭹ߤεĤ롣
.TP
.B S_IXOTH
00001 ¾ͤˤϼ¹ԤεĤ롣
.PP
.I flags 

.B O_CREAT
ꤵƤϡ
.I mode
ꤷʤФʤʤ
ʳξ̵뤵롣

.BR creat ()

.I flags

.B O_CREAT|O_WRONLY|O_TRUNC
ꤷ
.BR open ()
ԤΤǤ롣
.SH ֤
.BR open ()

.BR creat ()
Ͽե롦ǥץ֤
顼ȯ \-1 ֤
(ξ
.I errno
Ŭڤꤵ)
.BR open ()
ǥڥ롦ե򥪡ץ󤹤뤳ȤϤǤ뤬
.BR creat ()
ǥڥ롦եǤʤդ뤳ȡ
- 
.BR mknod (2)
Ѥ롣
.LP
UID ޥåԥ󥰤ѤƤ NFS ե롦ƥǤϡ
\fBopen\fP ե롦ǥץ֤Ǥ
\fBread\fP(2)  \fBEACCES\fP ǵݤ礬롣
ϥ饤ȤĤΥåԤä \fBopen\fP ¹Ԥ뤬
ɤ߹ߤ񤭹ߤκݤˤϥС UID ޥåԥ󥰤Ԥ뤿Ǥ롣

ե뤬ȡ
ե atime, ctime, mtime եɤ߻ꤵ롣
˿ƥǥ쥯ȥ ctime  mtime ⸽߻ꤵ롣
ʳξǡO_TRUNC ե饰ǥե뤬줿Ȥϡ
ե ctime  mtime եɤ߻ꤵ롣

.SH 顼
.TP
.B EACCES
եФ׵ᤵ줿Ƥʤ
.I pathname
Υǥ쥯ȥʬβ줫Υǥ쥯ȥ˸Ĥʤä
ޤϥե뤬¸ߤƥǥ쥯ȥؤν񤭹ߵĤʤä
.RB ( path_resolution (2)
⻲Ȥ뤳ȡ)
.TP
.B EEXIST
.I pathname
ϴ¸ߤ
.BR O_CREAT "  " O_EXCL
Ѥ줿
.TP
.B EFAULT
.I pathname
λؤΰ褬ǽʥɥ쥹֤ˤʤ
.TP
.B EISDIR
.I pathname
ϥǥ쥯ȥ򻲾ȤƤꡢ񤭹׵᤬ޤޤƤ
(Ĥޤ
.B O_WRONLY
ޤ
.B O_RDWR
ꤵƤ)
.TP
.B ELOOP
.I pathname
褹ݤܥå󥯤¿᤮롣
ޤ \fBO_NOFOLLOW\fR ꤵƤꡢ
.I pathname
ܥå󥯤ä
.TP
.B EMFILE
ץˡץǤեκãƤ롣
.TP
.B ENAMETOOLONG
.IR pathname " Ĺ᤮롣"
.TP
.B ENFILE
ץǤեι׿ƥ¤ãƤ롣
.TP
.B ENODEV
.I pathname
ǥХڥ롦ե򻲾ȤƤꡢбǥХ¸ߤʤ
( Linux ͥΥХǤꡢξˤ ENXIO ֤٤Ǥ)
.TP
.B ENOENT
O_CREAT ꤵƤ餺Ļꤵ줿ե뤬¸ߤʤ
ޤϡ
.I pathname
Υǥ쥯ȥʬ¸ߤʤ줿 (dangling) ܥå󥯤Ǥ롣
.TP
.B ENOMEM
ͥˡѤǤ꤬­Ƥ
.TP
.B ENOSPC
.I pathname
ɬפ뤬
.I pathname
ޤǤǥХ˿եΤζ̤ʤ
.TP
.B ENOTDIR
.I pathname
˴ޤޤǥ쥯ȥʬΤɤ줫ºݤˤϥǥ쥯ȥǤʤ
ޤ \fBO_DIRECTORY\fR ꤵƤꡢ
.I pathname
ǥ쥯ȥǤʤ
.TP
.B ENXIO
O_NONBLOCK | O_WRONLY ꤵƤꡢꤷե뤬 FIFO 
Υեɤ߹ߤΤ˥ץ󤷤Ƥץ¸ߤʤ
ޤϡե뤬ǥХڥ롦ե
бǥХ¸ߤʤ
.TP
.B EOVERFLOW
礭ƥץǤʤ̾Υե򻲾Ȥ -
嵭 O_LARGEFILE 򻲾ȡ
.TP
.B EPERM
.B O_NOATIME
ե饰ꤵ줿ƤӽФμ¸桼 ID 
.\" ̩˸СƤӽФΥե륷ƥ UID...(MTK) 
եνͭԤȰפĸƤӽФø
.RB ( CAP_FOWNER )
ʤ
.TP
.B EROFS
.I pathname
ɤ߹ѤΥե륷ƥΥե򻲾ȤƤꡢ
񤭹ߥ׵ᤵ줿
.TP
.B ETXTBSY
.I pathname
߼¹μ¹ԥ᡼򻲾ȤƤꡢ񤭹ߤ׵ᤵ줿
.SH 
Linux ǤϡO_NONBLOCK ե饰ϡ
open ¹Ԥ read ޤ write ¹Ԥտޤ
ɬʤȤ̣롣

.BR ioctl (2)
ΤΥեǥץ뤿ˡ
ǥХ򥪡ץ󤹤Ȥˤ褯Ѥ롣
.SH 
SVr4, SVID, POSIX, X/OPEN, BSD 4.3
.BR O_NOATIME ,
.BR O_NOFOLLOW ,
.B O_DIRECTORY
ե饰 Linux ͭΤΤǤ롣
Υե饰Ȥˤϡ
.B _GNU_SOURCE
ޥɬפ뤫⤷ʤ
.LP
.B O_RDONLY | O_TRUNC
 (Ƥʤ) ưϡˤäưۤʤ롣
¿ΥƥǤϥեϼºݤڤͤ롣
.\" Linux 2.0, 2.5: truncate
.\" Solaris 5.7, 5.8: truncate
.\" Irix 6.5: truncate
.\" Tru64 5.1B: truncate
.\" HP-UX 11.22: truncate
.\" FreeBSD 4.7: truncate
.LP
.B O_DIRECT
ե饰  SGI IRIX Ƴ졢
(桼Хåե) 饤Ȥ¤ Linux 2.4 ƱǤ롣
IRIX ˤŬڤ֤ȥ뤿 fcntl(2) 뤬롣
FreeBSD 4.x ⤳Υե饰Ƴ饤Ȥ¤Ϥʤ
Υե饰 Linux ǥݡȤ줿Τϡ
ͥС 2.4.10 Ǥ롣
Ť Linux ͥϡΥե饰ñ̵뤹롣
.SH Х
O_DIRECT ǤĤ⺤Τϡ󥿥եˤϼ
֤ʤޥɥȥޤ
Ƭʤä뤬߷פ󤸤ʤʡ -- Linus
.SH 
NFS ¸Ƥץȥˤ¿ꡢä
.BR O_SYNC "  " O_NDELAY 
˱ƶ롣

POSIX Ǥϡե饰 \fBO_SYNC\fR, \fBO_DSYNC\fR, \fBO_RSYNC\fR б
3 Ʊ I/O 󶡤Ƥ롣
Linux ǤϡΤȤ (ͥ 2.1.130) ƱΤǤ롣
.SH Ϣ
.BR close (2),
.BR fcntl (2),
.BR link (2),
.BR mknod (2),
.BR mount (2),
.BR path_resolution (2),
.BR read (2),
.BR socket (2),
.BR stat (2),
.BR umask (2),
.BR unlink (2),
.BR write (2),
.BR fopen (3),
.BR fifo (4)