.\" Copyright (c) 1993 Luigi P. Bai (lpb@softint.com) July 28, 1993
.\"
.\" 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.\" manual page may be incorrect or out-of-date.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 Wed Jul 28 10:57:35 1993, Rik Faith <faith@cs.unc.edu>
.\" Modified Sun Nov 28 16:43:30 1993, Rik Faith <faith@cs.unc.edu>
.\"          with material from Giorgio Ciucci <giorgio@crcc.it>
.\" Portions Copyright 1993 Giorgio Ciucci <giorgio@crcc.it>
.\" Modified Tue Oct 22 22:03:17 1996 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified, 8 Jan 2003, Michael Kerrisk, <mtk.manpages@gmail.com>
.\"	Removed EIDRM from errors - that can't happen...
.\" Modified, 27 May 2004, Michael Kerrisk <mtk.manpages@gmail.com>
.\"     Added notes on capability requirements
.\" Modified, 11 Nov 2004, Michael Kerrisk <mtk.manpages@gmail.com>
.\"	Language and formatting clean-ups
.\"	Added notes on /proc files
.\"
.\" Japanese Version Copyright (c) 1997 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated 1997-03-01, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated & Modified 2001-06-03, Yuichi SATO <ysato@h4.dion.ne.jp>
.\" Updated 2001-12-22, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2002-10-16, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2003-02-23, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2005-03-02, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2005-11-04, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2006-07-21, Akihiro MOTOKI, LDP v2.36
.\"
.\"WORD:	shared memory		ͭ
.\"WORD:	segment			
.\"WORD:	owner			ͭ
.\"WORD:	group			롼
.\"WORD:	world			¾
.\"WORD:	creator			
.\"WORD:	super-user		ѡ桼
.\"WORD:	detach			ʬΥ
.\"WORD:	attach			ղ
.\"WORD:	identifier		̻
.\"WORD:	member			С
.\"WORD:	effective user ID	¸桼ID
.\"WORD:	effective group ID	¸롼ID
.\"WORD:	policy			
.\"WORD:	implement		
.\"
.TH SHMGET 2 2006-05-02 "Linux" "Linux Programmer's Manual"
.SH ̾
shmget \- ͭꡦȤƤ
.SH 
.ad l
.B #include <sys/ipc.h>
.br
.B #include <sys/shm.h>
.sp
.BI "int shmget(key_t " key ", size_t " size ", int " shmflg );
.ad b
.SH 
.BR shmget ()

.I key
б붦ͭꡦȤμ̻Ҥ֤
.I key
ͤ
.B IPC_PRIVATE
ξ硢⤷
.I key
б붦ͭꡦȤ¸ߤ
.I shmflg

.B IPC_CREAT
ꤵƤ硢
ͭꡦȤ롣
붦ͭꡦȤϡ
.I size
ͤ
.B PAGE_SIZE
ܿؤڤ夲 (round up) 礭Ȥʤ롣
.PP
.I shmflg

.B IPC_CREAT

.B IPC_EXCL
ξꤵ줿硢
.I key
б붦ͭꡦȤ¸ߤȡ
.BR shmget ()
ϼԤ
.I errno

.B EEXIST
ꤵ (
.BR open (2)

.B O_CREAT | O_EXCL
ꤷưƱǤ)
.PP
.I shmflg
ϰʲƤ鹽:
.TP 12
.B IPC_CREAT
Ȥ롣Υե饰ꤵʤä硢
.BR shmget ()
 \fIkey\fP б륻Ȥõ
桼ΥȤ˥Ĥ뤫ɤå롣
.TP
.B IPC_EXCL
\fBIPC_CREAT\fP ȶ˻ѤȤ¸ߤˤ
Ԥ뤳Ȥݾڤ롣
.TP
.I mode_flags
( 9 ӥå)
ͭԡ롼ס¾ (world) ؤεĤꤹ롣
ΥӥåȤ
.BR open (2)

.I mode
ƱƱ̣ġ
ΤȤƥϼ¹ (execute) Ĥ򻲾Ȥʤ
.TP
.BR SHM_HUGETLB " (Linux 2.6 ʹ)"
"ҥ塼ڡ (huge page)" ȤȤƤ롣
ܺ٤ʾϡͥ롦Υե
.I Documentation/vm/hugetlbpage.txt
򻲾ȡ
.TP
.BR SHM_NORESERVE " (Linux 2.6.15 ʹ)"
Υե饰ϡ
.BR mmap (2)

.B MAP_NORESERVE
ե饰Ʊ̤
ΥȤФ륹å׶֤ͽԤʤ
å׶֤ͽ󤷤ϡΥȤѹɬ뤳Ȥ
ݾڤ롣å׶֤ͽԤʤäϡʪ˶
ʤȽ񤭹߻
.B SIGSEGV
ǽ롣
.BR proc (5)
ˤ
.I /proc/sys/vm/overcommit_memory
ե˴ؤ⻲ȤΤȡ
.\" As at 2.6.17-rc2, this flag has no effect if SHM_HUGETLB was also
.\" specified.
.PP
ͭꡦȤ˺ݡ
ͭꡦȤƤ 0 ǽ졢
Ϣݻǡ¤
.I shmid_ds
ϰʲΤ褦˽롣
.IP
.I shm_perm.cuid

.I shm_perm.uid
˸ƤӽФץμ¸ (effective) 桼ID ꤹ롣
.IP
.I shm_perm.cgid

.I shm_perm.gid
˸ƤӽФץμ¸롼ID ꤹ롣
.IP
.I shm_perm.mode
β 9 ӥåȤ
.I shmflg
β 9 ӥåȤꤹ롣
.IP
.I shm_segsz

.I size
ͤꤹ롣
.IP
.IR shm_lpid ,
.IR shm_nattch ,
.IR shm_atime ,
.I shm_dtime
 0 ꤹ롣
.IP
.I shm_ctime
˸ߤλꤹ롣
.PP
ͭꡦȤ¸ߤ硢Ĥθȡ
˲ (destruction) ޡĤƤʤΥåԤ롣
.SH ֤
硢ͭʥȼ̻
.I shmid
֤롣顼ξ硢 \-1 ֤롣
.SH 顼
Ԥ
.I errno
ʲΤɤ줫ꤵ:
.TP 12
.B EACCES
桼ϤζͭꡦȤؤΥĤ
.B CAP_IPC_OWNER
ѥӥƥäƤʤ
.TP
.B EEXIST
.B IPC_CREAT | IPC_EXCL
ꤵƤΥȤ¸ߤ롣
.TP
.B EINVAL
Ȥ褦Ȥݤ
\fIsize\fP < \fBSHMMIN\fP ޤ \fIsize\fP > \fBSHMMAX\fP Ǥä
⤷ϡꤵ줿б륻Ȥ¸ߤơ
Ȥ褦ȤϤʤä\fIsize\fP ¸ߤ륻Ȥ
礭ä
.TP
.B ENFILE
.\" [2.6.7] shmem_zero_setup()-->shmem_file_setup()-->get_empty_filp()
ƥΤǥץ󤵤Ƥե¤ã
.TP
.B ENOENT
ꤵ줿 \fIkey\fP б륻Ȥ¸ߤ
.B IPC_CREAT
ꤵƤʤä
.TP
.B ENOMEM
Ȥδ (overhead) ˳Ƥ꤬ʤä
.TP
.B ENOSPC
.\" motoki 2005-03-02 -- SHMMNI ΰ̣θư
ƥΤζͭꡦȿ
.RB ( SHMMNI )
ãޤ׵ᤵ줿
.I size
ΥȤγƤ
ƥΤζͭꥵ
.RB ( SHMALL )
Ķᤷ
.TP
.B EPERM
.B SHM_HUGETLB
ե饰ꤵ줿ƤӽФˤϸ¤ʤä
.RB ( CAP_IPC_LOCK
ѥӥƥäƤʤä)
.SH 
SVr4, POSIX.1-2001.
.\" SVr4 ˤɲä EEXIST 顼֤εҤ롣

.B SHM_HUGETLB
 Linux ǤγĥǤꡢܿϤʤ
.SH 
.B IPC_PRIVATE
ϥե饰ǤϤʤ
.I key_t
Ǥ롣
̤ͤ
.I key
˻Ѥ줿ϡ
.BR shmget ()

.I shmflg
β 9 ӥåȤƤ̵뤷
() ͭꡦȤ롣
.PP
.BR shmget ()
˱ƶ붦ͭꡦȻ񸻤¤ϰʲ̤Ǥ:
.TP 11
.B SHMALL
ƥΤζͭꡦڡκ
(Linux Ǥϡξͤ
.I /proc/sys/kernel/shmall
ͳǻȤꡢѹǤ)
.TP
.B SHMMAX
ͭꡦȤΥХñ̤礭ξ: ˰¸
(Linux Ǥϡξͤ
.I /proc/sys/kernel/shmmax
ͳǻȤꡢѹǤ)
.TP
.B SHMMIN
ͭꡦȤΥХñ̤礭β: ¸
(ߤ 1 ХȤ¼ŪʺǾ
.B PAGE_SIZE
Ǥ)
.TP
.B SHMMNI
ƥΤζͭ꡼οξ: ¸
(ߤ 4096Linux 2.3.99 Ǥ 128
Linux Ǥϡξͤ
.I /proc/sys/kernel/shmmni
ͳǻȤꡢѹǤ)
.\" 2.4.x  2.6.8 δ֤ΥͥˤϡSHMMNI Ĥ¿
.\" ȤǤȤХä
.\"  /proc ե Linux 2.2 ǤѤǤʤ -- MTK
.PP
ץζͭꡦȤθĿκ
.RB ( SHMSEG )
˴ؤ¤Ϥʤ
.SS Linux Ǥ
С 2.3.30 ޤǤϡLinux 
ͽꤵƤ붦ͭꡦȤФ
.BR shmget ()
Ԥ
.B EIDRM
֤Ƥ
.SH Х
.B IPC_PRIVATE
Ȥ̾ΤϤ餯ԤǤ
.B IPC_NEW
ΤˤεǽɽƤ
.SH Ϣ
.BR shmat (2),
.BR shmctl (2),
.BR shmdt (2),
.BR ftok (3),
.BR capabilities (7),
.BR svipc (7)