.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" This manpage is Copyright (C) 1992 Drew Eckhardt;
.\"                               1993 Michael Haardt, Ian Jackson.
.\"                               2008 Greg Banks
.\"
.\" 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.\" manual page may be incorrect or out-of-date.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@gmail.com>
.\" Modified 2004-06-23 by Michael Kerrisk <mtk.manpages@gmail.com>
.\" 2004-12-08, mtk, reordered flags list alphabetically
.\" 2004-12-08, Martin Pool <mbp@sourcefrog.net> (& mtk), added O_NOATIME
.\" 2007-09-18, mtk, Added description of O_CLOEXEC + other minor edits
.\" 2008-01-03, mtk, with input from Trond Myklebust
.\"     <trond.myklebust@fys.uio.no> and Timo Sirainen <tss@iki.fi>
.\"     Rewrite description of O_EXCL.
.\" 2008-01-11, Greg Banks <gnb@melbourne.sgi.com>: add more detail
.\"     on O_DIRECT.
.\" 2008-02-26, Michael Haardt: Reorganized text for O_CREAT and mode
.\"
.\" FIXME . Apr 08: The next POSIX revision has O_EXEC, O_SEARCH, and
.\" O_TTYINIT.  Eventually these may need to be documented.  --mtk
.\"
.\" Japanese Version Copyright (c) 1997-1999 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated 1999-08-14, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated 2001-05-25, Yuichi SATO <ysato444@yahoo.co.jp>
.\" Updated & Modified 2002-01-02, Yuichi SATO
.\" Updated & Modified 2002-07-07, Yuichi SATO
.\" Updated & Modified 2002-09-19, Yuichi SATO
.\" Updated & Modified 2003-07-30, Yuichi SATO
.\" Updated & Modified 2003-11-27, Yuichi SATO
.\" Updated & Modified 2005-01-01, Yuichi SATO
.\" Updated & Modified 2005-09-14, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated & Modified 2005-10-14, Akihiro MOTOKI
.\" Updated & Modified 2006-01-18, Akihiro MOTOKI
.\" Updated & Modified 2006-04-15, Akihiro MOTOKI, LDP v2.29
.\" Updated 2007-01-07, Akihiro MOTOKI, LDP v2.43
.\" Updated 2007-05-01, Akihiro MOTOKI, LDP v2.46
.\" Updated 2007-10-12, Akihiro MOTOKI, LDP v2.66
.\" Updated 2008-02-12, Akihiro MOTOKI, LDP v2.77
.\" Updated 2008-04-04, Akihiro MOTOKI, LDP v2.79
.\" Updated 2008-08-08, Akihiro MOTOKI, LDP v3.05
.\"
.\"WORD:	descriptor		ǥץ
.\"WORD:	file description	ե뵭
.\"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
.\"WORD:	file creation flag	եե饰
.\"WORD:	file status flag	ե֥ե饰
.\"
.TH OPEN 2 2008-12-03 "Linux" "Linux Programmer's Manual"
.SH ̾
open, creat \- եǥХΥץ󡢺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 
ե
.I pathname
Ϳȡ
.BR open ()
ϥե롦ǥץ֤
ե롦ǥץϡθ³ƥॳ
.RB ( read "(2), " write "(2), " lseek "(2), " fcntl "(2) ʤ)"
ǻѤ뾮Ǥ롣
Υƥॳ뤬֤ե롦ǥץ
Υץλǥץ󤷤Ƥʤե롦ǥץ
ǾοΤΤȤʤ롣
.PP
ǥեȤǤϡե롦ǥץ
.BR execve (2)
¹Ԥ⥪ץ󤵤줿ޤޤȤʤ (Ĥޤꡢ
.BR fcntl (2)

.B FD_CLOEXEC
ե롦ǥץե饰Ϻǽ̵Ǥ;
Ҥ Linux ͭΥե饰
.B O_CLOEXEC
ȤȤΥǥեȤѹ뤳ȤǤ)
ե롦եå (file offset) ϥեƬꤵ
.RB ( lseek (2)
)
.PP
.BR open ()
ƤӽФȡ֥ץե뵭ҡ
.I "(open file description)"
롣ե뵭ҤȤϡƥΤ
ץΥեΥơ֥ΥȥǤ롣
Υȥϡե롦եåȤȥե֥ե饰
.RB ( fcntl (2)
.B F_SETFL
ˤѹǽ) ݻ롣
ե롦ǥץϤΥȥΰĤؤλȤǤ롣
θ
.I pathname
줿ꡢ¾Υե򻲾Ȥ褦ѹ줿ꤷƤ⡢
λȤϱƶʤ
ץե뵭ҤϺǽ¾ΤɤΥץȤ
ͭƤʤ
.BR fork (2)
Ƕͭ礬롣
.PP

.I flags
ˤϡ⡼
.BR O_RDONLY ", " O_WRONLY ", " O_RDWR
Τɤ줫ҤȤĤäƤʤФʤʤ
Ϥ줾ɤ߹ѡ񤭹ѡɤ߽Ѥ
ե򥪡ץ󤹤뤳Ȥ׵᤹ΤǤ롣

ˡ
.I flags
ˤϡեե饰 (file creation flag) ȥե֥ե饰
(file status flag)  0 İʾ֥ӥåñ̤ OR (bitwise-or)פ
ꤹ뤳ȤǤ롣
.I եե饰

.BR O_CREAT ", " O_EXCL ", " O_NOCTTY ", " O_TRUNC
Ǥ롣
.I ե֥ե饰
ϰʲΥꥹȤΤ嵭ʳλĤΤΤǤ롣
.\" FIXME . Actually is it true that the "file status flags" are all of the
.\" remaining flags listed below?  SUSv4 divides the flags into:
.\" * Access mode
.\" * File creation
.\" * File status
.\" * Other (O_CLOEXEC, O_DIRECTORY, O_NOFOLLOW)
.\" though it's not clear what the difference between "other" and
.\" "File creation" flags is.  (I've raised an Aardvark to see if this
.\" can be clarified in SUSv4; 10 Oct 2008.)
Υե饰ΰ㤤ϡե֥ե饰
.BR fcntl (2)
ȤäƤƤ (ˤäƤ) ѹǤˤ롣
եե饰ȥե֥ե饰ꥹȤʲ˼:
.TP
.B O_APPEND
եɲ (append) ⡼ɤǥץ󤹤롣

.BR write (2)

.BR lseek (2)
ԤäΤ褦ˡե롦ݥ󥿡եκǸ˰ư롣
.\" For more background, see
.\" http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=453946
.\" http://nfs.sourceforge.net/
NFS ե롦ƥǡ
.B O_APPEND
ѤȡʣΥץҤȤĤΥեƱ˥ǡɲä硢
ե뤬ƤޤȤ롣
 NFS ɲå⡼ɤ򥵥ݡȤƤʤᡢ
饤ȤΥͥ (kernel) 򥷥ߥ졼ȤʤФʤʤΤ
֤򤱤뤳ȤϤǤʤǤ롣
.TP
.B O_ASYNC
ʥư I/O (signal-driven I/O) ͭˤ:
Υե롦ǥץؤ
ϤޤϽϤǽˤʤäˡʥ
(ǥեȤ
.B SIGIO
Ǥ뤬
.BR fcntl (2)
ˤäѹǽǤ)
εǽѲǽʤΤüüåȤΤߤǤꡢ
(Linux 2.6 ʹߤǤ) ѥפ FIFO ФƤѤǤ롣
˾ܤ
.BR fcntl (2)
򻲾Ȥ뤳ȡ
.TP
.BR O_CLOEXEC " (Linux 2.6.23 ʹ)"
ե롦ǥץФ close-on-exec ե饰ͭˤ롣
Υե饰ꤹ뤳Ȥǡץ
.B FD_CLOEXEC
ե饰򥻥åȤ뤿
.BR fcntl (2)
.B F_SETFD
ӸƤӽФɬפʤʤ롣
ޤΥޥåɤΥץϤΥե饰λѤ
ԲķǤ롣ʤʤ顢̤
.B FD_CLOEXEC
ե饰ꤹ
.BR fcntl (2)
.B F_SETFD
ƤӽФȤƤ⡢륹åɤեǥץ
ץ󤹤ΤƱ̤Υåɤ
.BR fork (2)

.BR execve (2)
¹ԤȤ򤱤ΤˤϽʬǤϤʤǤ롣
.\" This flag fixes only one form of the race condition;
.\" The race can also occur with, for example, descriptors
.\" returned by accept(), pipe(), etc.
.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
.BR mount (8)
Ƥޥȥץ
.I bsdgroups

.I sysvgroups
򻲾)
.\" 2.6.25 Ǥϡbsdgroups  ext2, ext3, ext4, XFS ǥݡ
.\" Ƥ (2.6.14 ʹ)
.RS
.PP
.I mode
Ͽե˻Ѥ륢 (permission) ꤹ롣
.I flags

.B O_CREAT
ꤵƤ硢
.I mode
ꤷʤФʤʤ
.B O_CREAT
ꤵƤʤ硢
.I mode
̵뤵롣
ͭʥĤϡʤƱ褦˥ץ
.I umask
ˤäƽ졢줿եεĤ
.I "(mode\ &\ ~umask)"
Ȥʤ롣
Υ⡼ɤϡ줿եФ뤽ʹߤΥ
ˤΤŬѤդ뤳ȡ
ɤ߼ѤΥե
.BR open ()
ǤäƤ⡢
ɤ߽񤭲ǽʥե롦ǥץ֤Ȥꤦ롣
.PP
.I mode
Τ˰ʲΥܥ󶡤Ƥ :
.TP 9
.B S_IRWXU
00700 桼 (եνͭ) ɤ߹ߡ񤭹ߡ
¹ԤεĤ롣
.TP
.B S_IRUSR
00400 桼ɤ߹ߤεĤ롣
.TP
.B S_IWUSR
00200 桼˽񤭹ߤεĤ롣
.TP
.B S_IXUSR
00100 桼˼¹ԤεĤ롣
.TP
.B S_IRWXG
00070 롼פɤ߹ߡ񤭹ߡ¹ԤεĤ롣
.TP
.B S_IRGRP
00040 롼פɤ߹ߤεĤ롣
.TP
.B S_IWGRP
00020 롼פ˽񤭹ߤεĤ롣
.TP
.B S_IXGRP
00010 롼פ˼¹ԤεĤ롣
.TP
.B S_IRWXO
00007 ¾ (others) ɤ߹ߡ񤭹ߡ¹ԤεĤ롣
.TP
.B S_IROTH
00004 ¾ͤɤ߹ߤεĤ롣
.TP
.B S_IWOTH
00002 ¾ͤ˽񤭹ߤεĤ롣
.TP
.B S_IXOTH
00001 ¾ͤ˼¹ԤεĤ롣
.RE
.TP
.BR O_DIRECT " (Linux 2.4.10 ʹ)"
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)
λǡǡžλȤݾڤ롣
աפ () ε⻲ȡ
.sp
֥åǥХФ̤ạ̈Υ󥿡ե
.BR raw (8)
Ƥ (âΥ󥿥ե侩Ǥ)
.TP
.B O_DIRECTORY
\fIpathname\fP ǥ쥯ȥǤʤХץϼԤ롣
.\" ʲεȤΥץ饤򻲾ȤΤȡ
.\" http://marc.theaimsgroup.com/?t=112748702800001&r=1&w=2
.\" [PATCH] open: O_DIRECTORY and O_CREAT together should fail
.\" O_DIRECTORY | O_CREAT ꤹ O_DIRECTORY ̵뤵Ƥޤ
Υե饰 Linux ͭǤꡢ
.BR opendir (3)
 FIFO ơץǥХФƥ뤵줿
ӥǽ (denial-of-service) 򤱤뤿
ͥ 2.1.126 ɲä줿

.BR opendir (3)
μʳǤϻѤ٤ǤϤʤ
.TP
.B O_EXCL
θƤӽФǥե뤬뤳Ȥݾڤ롣
Υե饰
.B O_CREAT
Ȱ˻ꤵ졢
.I pathname
Υե뤬¸ߤ硢
.BR open ()
ϼԤ롣
.B O_CREAT
ꤵʤä
.B O_EXCL
ư̤Ǥ롣

ĤΥե饰ꤵ줿ݡܥå󥯤éʤ
.\" POSIX.1-2001 ǤŪˤư׵ᤷƤ롣
.I pathname
ܥå󥯤ξ硢
ܥå󥯤ɤؤƤ뤫˴ؤ餺
.BR open ()
ϼԤ롣

.B O_EXCL
ϡLinux 2.6 ʹߤ NFSv3 ʹߤȤäƤ NFS ǤΤߥݡȤƤ롣
NFS 
.B O_EXCL
ݡȤ󶡤ƤʤĶǤϡΥե饰ä
å¹Ԥץ϶ (race condition) ˽в
ǽ롣
åեѤԲʬ (atomic) ʥեå¸
NFS 
.B O_EXCL
򥵥ݡȤƤ뤫˰¸ʤ褦ˤ硢
ܿΤˡϡƱե륷ƥ¾̾νŤʤʤ
ե (㤨Хۥ̾ PID Ȥ߹碌̾) 
.BR link (2)
ѤƤΥåեؤΥ󥯤뤳ȤǤ롣
.BR link (2)
֤ͤ 0 ʤХåƤ롣
뤤ϡΥե
.BR stat (2)
Ѥƥ󥯿 (link count)  2 ˤʤäƤ뤫å롣
ʤäƤСƱåƤȤȤǤ롣
.TP
.B O_LARGEFILE
(LFS)
.I off_t
Ǥϥɽʤ (
.I off64_t
Ǥϥɽ) ե򥪡ץǽˤ롣
ͭˤ뤿ˤϡ
.B _LARGEFILE64_SOURCE
ޥʤФʤʤ
32ӥåȥƥˤ礭ʥե˥ˡ硢
.RB ( O_LARGEFILE
Ȥ)
.B _FILE_OFFSET_BITS
ǽޥ򥻥åȤ˾ޤˡǤ
.RB ( feature_test_macros (7)
򻲾)
.TP
.BR O_NOATIME " (Linux 2.6.8 ʹ)"
եФ
.BR read (2)
¹Ԥ줿Ȥˡǽ (inode  st_atime) 򹹿ʤ
Υե饰ϥǥåХååץץǻȤȤտޤƤ롣
ȤȥǥФ˸餹ȤǤ롣
Υե饰ƤΥե륷ƥФͭǤ櫓ǤϤʤ
ΰ㤬 NFS ǤꡢФƤ롣
.\" The O_NOATIME flag also affects the treatment of st_atime
.\" by mmap() and readdir(2), MTK, Dec 04.
.TP
.B O_NOCTTY
.I pathname
ü (terminal) ǥХ
\(em
.BR tty (4)

\(em
ؤƤˡȤΥץüäƤʤƤ⡢
ץ󤷤եüˤϤʤʤ
.TP
.B O_NOFOLLOW
\fIpathname\fP 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\fP
.TP
.BR O_NONBLOCK " ޤ " O_NDELAY
ǽʤСե (non-blocking) ⡼ɤǥץ󤵤롣
.BR open ()
⡢֤ե롦ǥץФʸΤ٤Ƥ
ƤӽФץԤ뤳ȤϤʤ
FIFO (͡ɡѥ) 򰷤ˤ
.BR fifo (7)
⻲Ȥ뤳ȡ
եå (mandatory file lock) ե꡼ (file lease)
Ȥ߹碌Ρ
.B O_NONBLOCK
θ̤ˤĤƤεϡ
.BR fcntl (2)
򻲾Ȥ뤳ȡ
.TP
.B O_SYNC
եƱ (synchronous) I/O ⡼ɤǥץ󤵤롣
.BR open ()
֤ե롦ǥץФ
.BR write (2)
ԤȡɬƤӽФץ֥å
ϡɥʪŪ˽񤭹ޤޤ֤ʤ
.I ʲΡաפξϤ⻲ȡ
.TP
.B O_TRUNC
ե뤬¸ߤ̾եǤꡢ
񤭹߲ĥ⡼ɤǥץ󤵤Ƥ
(Ĥޤꡢ
.BR O_RDWR "ޤ" O_WRONLY
) 硢Ĺ 0 ڤͤ (truncate) 롣
ե뤬 FIFO ޤüǥХեξ硢
.B O_TRUNC
ե饰̵뤵롣
ʳξ硢
.B O_TRUNC
θ̤̤Ǥ롣
.PP
ե饰ΤĤϥե򥪡ץ󤷤Ǥ
.BR fcntl (2)
Ѥѹ뤳ȤǤ롣

.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)
.SH 顼
.TP
.B EACCES
եФ׵ᤵ줿Ƥʤ
.I pathname
Υǥ쥯ȥʬβ줫Υǥ쥯ȥ˸Ĥʤä
ޤϥե뤬¸ߤƥǥ쥯ȥؤν񤭹ߵĤʤä
.RB ( path_resolution (7)
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 EFBIG
.B EOVERFLOW
ȡ
.TP
.B EINTR
٤ǥХ
(㤨 FIFO
.BR fifo (7)
) Υץ󤬴λΤԤäߤƤ֤
ƥॳ뤬ʥϥɥˤޤ줿
.BR signal (7)
ȡ
.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\fP ꤵƤꡢ
.I pathname
ܥå󥯤ä
.TP
.B EMFILE
ץץ󤷤ƤեǤ˺ãƤ롣
.TP
.B ENAMETOOLONG
.I pathname
Ĺ᤮롣
.TP
.B ENFILE
ץǤեι׿ƥ¤ãƤ롣
.TP
.B ENODEV
.I pathname
ǥХڥ롦ե򻲾ȤƤꡢбǥХ¸ߤʤ
( Linux ͥΥХǤꡢξˤ
.B ENXIO
֤٤Ǥ)
.TP
.B ENOENT
.B O_CREAT
ꤵƤ餺Ļꤵ줿ե뤬¸ߤʤ
ޤϡ
.I pathname
Υǥ쥯ȥʬ¸ߤʤ줿 (dangling) ܥå󥯤Ǥ롣
.TP
.B ENOMEM
ͥѤǤ꤬­Ƥ
.TP
.B ENOSPC
.I pathname
ɬפ뤬
.I pathname
ޤǤǥХ˿եΤζ̤ʤ
.TP
.B ENOTDIR
.I pathname
˴ޤޤǥ쥯ȥʬΤɤ줫ºݤˤϥǥ쥯ȥǤʤ
ޤ \fBO_DIRECTORY\fP ꤵƤꡢ
.I pathname
ǥ쥯ȥǤʤ
.TP
.B ENXIO
.BR O_NONBLOCK " | " O_WRONLY
ꤵƤꡢꤷե뤬 FIFO 
Υեɤ߹ߤΤ˥ץ󤷤Ƥץ¸ߤʤ
ޤϡե뤬ǥХڥ롦ե
бǥХ¸ߤʤ
.TP
.B EOVERFLOW
.I pathname
ȤƤΤ礭᤮ƥץǤʤ̾ΥեǤ롣
̾Υ顼ȯϡ32 ӥåȥץåȥե
.I -D_FILE_OFFSET_BITS=64
ꤻ˥ѥ뤵줿ץꥱ󤬡ե륵
.I (2<31)-1
ӥåȤĶե򳫤ȤǤ롣
嵭
.B O_LARGEFILE
⻲ȡ
 POSIX.1-2001 ǵꤵƤ륨顼Ǥ롣
2.6.24 ΥͥǤϡLinux Ϥξ˥顼
.B EFBIG
֤Ƥ
.\" See http://bugzilla.kernel.org/show_bug.cgi?id=7253
.\" "Open of a large file on 32-bit fails with EFBIG, should be EOVERFLOW"
.\" Reported 2006-10-03
.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
.TP
.B EWOULDBLOCK
.B O_NONBLOCK
ե饰ꤵ줿Υեˤ̷⤹꡼ꤵƤ
.RB ( fcntl (2)
)
.SH 
SVr4, 4.3BSD, POSIX.1-2001.
ե饰
.BR O_DIRECTORY ,
.BR O_NOATIME ,
.B O_NOFOLLOW
 Linux ͭΤΤǤꡢ
Υե饰뤿ˤϡ
.B _GNU_SOURCE
ɬפ뤫⤷ʤ

.BR O_CLOEXEC
ե饰 POSIX.1-2001 ǤϵꤵƤʤ
POSIX.1-2008 ǵꤵƤ롣

.B O_DIRECT
 POSIX ǤϵꤵƤʤ
.B O_DIRECT
ˤ
.B _GNU_SOURCE
ʤФʤʤ
.SH 
Linux Ǥϡ
.B O_NONBLOCK
ե饰ϡ
open ¹Ԥ read ޤ write ¹Ԥտޤ
ɬʤȤ̣롣

.BR ioctl (2)
ΤΥեǥץ뤿ˡ
ǥХ򥪡ץ󤹤Ȥˤ褯Ѥ롣

֥⡼ɡפ
.BR O_RDONLY ", " O_WRONLY ", " O_RDWR
ϡ
.I flags
˻Ǥ¾ͤȰ㤤ġΥӥåȤꤹΤǤϤʤ
ͤ
.I flags
β 2 ӥåȤ롣
.BR O_RDONLY ", " O_WRONLY ", " O_RDWR
Ϥ줾 0, 1, 2 Ƥ롣
ȡ
.B "O_RDONLY | O_WRONLY"
Ȥ߹碌Ū˴ְ㤤ǤꡢΤ
.B O_RDWR
Ʊ̣ǤϤʤ
Linux Ǥϡ̤ʡɸʥ⡼ɤȤ 3 (ХʥǤ 11) 
ͽ󤵤Ƥ
.I flags
˻Ǥ롣
Υ⡼ɤꤹȡեɤ߽Ф/񤭹ߵĤå
ɤ߽Фˤ񤭹ߤˤѤǤʤǥץ֤
ɸΥ⡼ɤϤĤ Linux ɥ饤ФǻѤƤꡢ
ǥХͭ
.BR ioctl (2)
ˤΤ߻Ѥǥץ֤˻ȤƤ롣
.\" See for example util-linux's disk-utils/setfdprm.c
.\" For some background on access mode 3, see
.\" http://thread.gmane.org/gmane.linux.kernel/653123
.\" "[RFC] correct flags to f_mode conversion in __dentry_open"
.\" LKML, 12 Mar 2008
.LP
.B O_RDONLY | O_TRUNC
αƶ̤Ǥꡢưϼˤäưۤʤ롣
¿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
.PP
NFS ¸Ƥץȥˤ¿ꡢä
.BR O_SYNC "  " O_NDELAY
˱ƶ롣

POSIX Ǥϡե饰 \fBO_SYNC\fP, \fBO_DSYNC\fP, \fBO_RSYNC\fP б
3 Ʊ I/O 󶡤Ƥ롣
Linux ǤϡΤȤ (ͥ 2.1.130) ƱΤǤ롣

.BR open ()
ϥڥ롦ե򥪡ץ󤹤뤳ȤǤ뤬
.BR creat ()
ǥڥ롦եǤʤդ뤳ȡ

.BR mknod (2)
Ѥ롣
.LP
UID ޥåԥ󥰤ѤƤ NFS ե롦ƥǤϡ
.BR open ()
ե롦ǥץ֤Ǥ
.BR read (2)
 \fBEACCES\fP ǵݤ礬롣
ϥ饤ȤĤΥåԤä
.BR open ()
¹Ԥ뤬ɤ߹ߤ񤭹ߤκݤˤ
С UID ޥåԥ󥰤Ԥ뤿Ǥ롣

ե뤬ȡ
ե
.IR st_atime ,
.IR st_ctime ,
.I st_mtime
ե
(줾ǽǽѹǽǤ롣
.BR stat (2)
) ߻ꤵ롣
˿ƥǥ쥯ȥ
.I st_ctime

.I st_mtime
⸽߻ꤵ롣
ʳξǡO_TRUNC ե饰ǥե뤬줿Ȥϡ
ե
.I st_ctime

.I st_mtime
եɤ߻ꤵ롣
.SS O_DIRECT
.LP
.B O_DIRECT
ե饰Ѥ硢桼֥ХåեĹ䥢ɥ쥹
I/O Υե륪եåȤ˴ؤƥ饤Ȥ¤ݤ뤳Ȥ롣
Linux Ǥϡ饤Ȥ¤ϥե륷ƥ䥫ͥΥС
äưۤʤꡢ¤¸ߤʤ⤢롣
ʤ顢ߤΤȤꤵ줿եե륷ƥФ
¤뤫򸫤Ĥ뤿ΡץꥱΥ󥿥ե
ե륷ƥ¸ΤΤ¸ߤʤ
ĤΥե륷ƥǤϡ¤ǧ뤿ȼΥ󥿥ե
󶡤Ƥ롣㤨С
.BR xfsctl (3)

.B XFS_IOC_DIOINFO
̿Ǥ롣
.LP
Linux 2.4 Ǥϡž
桼ХåեΥ饤ȡե륪եåȤϡ
ե륷ƥ֥åܿǤʤФʤʤ
Linux 2.6 Ǥϡ512 ХȤȤζ֤ƤнʬǤ롣
.LP
.B O_DIRECT
ե饰  SGI IRIX Ƴ줿SGI IRIX ˤ Linux 2.4 Ʊͤ
(桼Хåե) 饤Ȥ¤롣
ޤIRIX ˤŬڤ֤ȥ뤿
.BR fcntl (2)
뤬롣
FreeBSD 4.x Ʊ̾Υե饰Ƴ饤Ȥ¤Ϥʤ
.LP
.B O_DIRECT
 Linux ǥݡȤ줿ΤϡͥС 2.4.10 Ǥ롣
Ť Linux ͥϡΥե饰ñ̵뤹롣
.B O_DIRECT
ե饰򥵥ݡȤƤʤե륷ƥ⤢ꡢξϡ
.B O_DIRECT
Ѥ
.BR open ()

.B EINVAL
ǼԤ롣
.LP
ץꥱϡƱե롢
äƱեνʣХΰФơ
.B O_DIRECT
̾ I/O 򺮤ƻȤΤ򤱤٤Ǥ롣
ե륷ƥबΤ褦ʾˤư
ȤǤǤäƤ⡢Τ I/O 롼ץåȤ
ɤ餫ѤȤ٤®ˤʤǤ
ƱͤˡץꥱϡƱեФ
.BR mmap (2)
ľ I/O
.RB ( O_DIRECT )
򺮤ƻȤΤ򤱤٤Ǥ롣
.LP
NFS 
.B O_DIRECT
ȤäưϥΥե륷ƥξȰ㤦
Ťͥ䡢ǥѥ뤵줿ͥϡ
.B O_DIRECT
 NFS Ȥ߹碌򥵥ݡȤƤʤ⤷ʤ
NFS ץȥ뼫ΤϥФ˥ե饰ϤǽϻäƤʤΤǡ
.B O_DIRECT
I/O ϥ饤ȾΥڡåХѥˤʤꡢ
Ф I/O 򥭥å夷Ƥ뤫⤷ʤ
饤Ȥϡ
.B O_DIRECT
Ʊݻ뤿ᡢФФ I/O ƱƹԤ褦˰ꤹ롣
ФˤäƤϡä I/O 
ǽ礭롣
ޤФˤäƤϡI/O ꤷȥ졼ˤޤǹԤ줿ȡ
饤ȤФƱĤΤ⤢롣
ϡФŸξ㤬äݤ˥ǡδݤʤ
Ͼ뤬ǽ̤Ǥʾ򤹤뤿˹ԤƤ롣
Linux  NFS 饤ȤǤ
.B O_DIRECT
I/O 
ǤΥ饤Ȥ¤Ϥʤ
.PP
ޤȤȡ
.B O_DIRECT
ϡդƻȤ٤Ǥ뤬ϤʥġȤʤǽäƤ롣
ץꥱ
.B O_DIRECT
ǥեȤǤ̵ˤʤäƤǽΤΥץ
ͤƤΤ褤Ǥ
.PP
.RS
O_DIRECT ǤĤ⺤Τϡ󥿥եˤϼ
֤ʤޥɥȥޤ
Ƭʤä뤬߷פ󤸤ʤʡ \(em Linus
.RE
.SH Х
ߤΤȤ
.BR open ()
θƤӽФ
.B O_ASYNC
ꤷƥʥư I/O ͭˤ뤳ȤϤǤʤ
Υե饰ͭˤˤ
.BR fcntl (2)
Ѥ뤳ȡ
.\" FIXME . Check bugzilla report on open(O_ASYNC)
.\" See http://bugzilla.kernel.org/show_bug.cgi?id=5993
.SH Ϣ
.BR chmod (2),
.BR chown (2),
.BR close (2),
.BR dup (2),
.BR fcntl (2),
.BR link (2),
.BR lseek (2),
.BR mknod (2),
.BR mmap (2),
.BR mount (2),
.BR openat (2),
.BR read (2),
.BR socket (2),
.BR stat (2),
.BR umask (2),
.BR unlink (2),
.BR write (2),
.BR fopen (3),
.BR feature_test_macros (7),
.BR fifo (7),
.BR path_resolution (7),
.BR symlink (7)