.\" Copyright 1993 Giorgio Ciucci (giorgio@crcc.it)
.\"
.\" 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.\" manual page may be incorrect or out-of-date.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 1996-10-22, Eric S. Raymond <esr@thyrsus.com>
.\" Modified 2002-01-08, Michael Kerrisk <mtk.manpages@gmail.com>
.\" Modified 2003-04-28, Ernie Petrides <petrides@redhat.com>
.\" Modified 2004-05-27, Michael Kerrisk <mtk.manpages@gmail.com>
.\" Modified, 11 Nov 2004, Michael Kerrisk <mtk.manpages@gmail.com>
.\"	Language and formatting clean-ups
.\"	Added notes on /proc files
.\" 2005-04-08, mtk, Noted kernel version numbers for semtimedop()
.\" 2007-07-09, mtk, Added an EXAMPLE code segment.
.\"
.\" Japanese Version Copyright (c) 1997 HANATAKA Shinya
.\"         all rights reserved.
.\" Translated 1997-02-23, HANATAKA Shinya <hanataka@abyss.rim.or.jp>
.\" Updated 2003-02-09, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2003-09-12, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2005-03-01, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\" Updated 2005-04-17, Akihiro MOTOKI
.\" Updated 2005-09-06, Akihiro MOTOKI
.\" Updated 2007-05-01, Akihiro MOTOKI, LDP v2.46
.\"
.\"WORD:	semaphore		ޥե
.\"WORD:	member			С
.\"WORD:	process			ץ
.\"WORD:	system call		ƥॳ
.\"WORD:	undo			ɥ
.\"WORD:	signal			ʥ
.\"WORD:	catch			(catch)
.\"WORD:	process-ID		ץID
.\"WORD:	policy			
.\"WORD:	implement		
.\"WORD:	queue			塼
.\"WORD:	free			(free).
.\"WORD:	memory			
.\"WORD:	anonymous structure	̵̾¤
.\"WORD:	time limit		»
\"
.TH SEMOP 2 2008-10-04 "Linux" "Linux Programmer's Manual"
.SH ̾
semop, semtimedop \- ޥե
.SH 
.nf
.B #include <sys/types.h>
.B #include <sys/ipc.h>
.B #include <sys/sem.h>
.sp
.BI "int semop(int " semid ", struct sembuf *" sops ", unsigned " nsops );
.sp
.BI "int semtimedop(int " semid ", struct sembuf *" sops ", unsigned " nsops ,
.BI "               struct timespec *" timeout );
.fi
.sp
.in -4n
glibc εǽޥ׷
.RB ( feature_test_macros (7)
):
.in
.sp
.BR semtimedop ():
_GNU_SOURCE
.SH 
ޥե (semaphore set) ΥСγƥޥե
ʲδϢäƤ:
.sp
.in +4n
.nf
unsigned short  semval;   /* ޥե */
unsigned short  semzcnt;  /* Ԥĥץ */
unsigned short  semncnt;  /* äԤĥץ */
pid_t           sempid;   /* ǸԤʤäץ */
.sp
.in -4n
.fi
.BR semop ()

.I semid
ǻꤵ줿ޥե򤵤줿ޥեФԤ
.I sops

.I nsops
ĤǤؤγǤϸġΥޥե
Ф򼨤η
.I struct sembuf
ǡΥФ:
.sp
.in +4n
.nf
unsigned short sem_num;  /* ޥեֹ */
short          sem_op;   /* ޥե */
short          sem_flg;  /* ե饰 */
.sp
.in -4n
.fi
.I sem_flg
ˤ
.B IPC_NOWAIT

.B SEM_UNDO
Ǥ롣
.B SEM_UNDO
ꤵ줿ϡΥץλ˼ưŪ˼ä롣
.PP
.I sops
˴ޤޤνϡ
.I "ν"
ǡ
.I ȥߥå
¹Ԥ롣
ʤƤ˼¹Ԥ뤫¹Ԥʤ
ɤ餫Ȥʤ롣

Ƥľ˼¹ԤǤʤΤΥƥॳο񤤤
ġ
.I sem_flg
եɤ
.B IPC_NOWAIT
¸ߤ뤫ˤäƷޤꡢҤΤ褦ˤʤ롣

줾ϥޥե
.IR sem_num 
ΥޥեФƼ¹Ԥ롣ޥեκǽΥޥեˤ
ֹ 0 롣
ϻढꡢ
.I sem_op
ͤǶ̤롣
.PP
.I sem_op
ξ硢ȤƤͤ򥻥ޥե
.RI ( semval )
˲ä롣ˤ
.B SEM_UNDO
ꤵƤϡƥϤΥޥե ץɥ
.RI ( semadj )
򹹿롣
ɬ¹ԤǤץߤϵʤ
ƤӽФץоݤΥޥեѹĤʤФʤʤ
.PP
.I sem_op
 0 ξ硢֥ޤԤġǤ롣ξ硢ץ
ΥޥեФɤ߹ߵĤʤФʤʤ
.I semval
 0 ʤСľ˹Ԥ롣
.I semval
 0 Ǥʤ硢
.I sem_flg

.B IPC_NOWAIT
ꤵƤС
.BR semop ()
ϼԤ
.B errno

.B EAGAIN
ꤵ (ΤȤ
.I sops
Ф¹Ԥʤ)
.I sem_flg

.B IPC_NOWAIT
ꤵƤʤ硢
.I semzcnt
(ޥեͤ 0 ˤʤΤԤäƤץο)  1 äơ
ʲΤ줫ޤǥץ (sleep) 롣
.IP \(bu 3
.I semval
 0 ˤʤä: ΤȤ
.I semval
ͤ 1 롣
.IP \(bu
ޥե礬줿: ΤȤ
.BR semop ()
ϼԤ
.I errno

.B EIDRM
ꤵ롣
.IP \(bu
ƤӽФץʥͤ: ΤȤ
.I semzcnt
ͤ 1 졢
.BR semop ()
ϼԤ
.I errno

.B EINTR
ꤵ롣
.IP \(bu
.\" motoki: semop ()  semtimedop () δְ㤤
.BR semtimedop ()

.I timeout
ǻꤵ줿»֤вᤷ: ΤȤ
.BR semtimedop ()
ϼԤ
.I errno

.B EAGAIN
ꤵ롣
.PP
.I sem_op
 0 ̤ξ硢ץˤϤΥޥեѹĤʤ
ʤʤ
.I semval

.I sem_op
Ͱʾξϡľ˼¹Ԥ:
.I semval

.I sem_op
ͤ롣
ˡ
.B SEM_UNDO
ꤵƤϡΥޥեΥץɥ
.RI ( semadj )
򹹿롣
.I semval

.I sem_op
ͤ꾮
.I sem_flg

.B IPC_NOWAIT
ꤵ줿ϡ
.BR semop ()
ϼԤ
.I errno

.B EAGAIN
ꤵ (ΤȤ
.I sops
¹Ԥʤ)
.B IPC_WAIT
ꤵƤʤС
.I semncnt
(ΥޥեͤäΤԤäƤץΥ)
 1 äơʲΤ줫ޤǥץ (sleep) 롣
.IP \(bu 3
.I semval

.I sem_op
Ͱʾˤʤä: ΤȤ
.I semncnt
 1 졢
.I semval

.I sem_op
ͤ롣

.B SEM_UNDO
ꤵƤˤϤΥޥեΥץɥ
.RI ( semadj )
⹹롣
.IP \(bu
ޥե礬ƥफ줿: ΤȤ
.BR semop ()
ϼԤ
.I errno

.B EIDRM
ꤵ롣
.IP \(bu
ƤӽФץʥͤ: ΤȤ
.I semncnt
 1 졢
.BR semop ()
ϼԤ
.I errno

.B EINTR
ꤵ롣
.IP \(bu
.\" motoki: the system call  semtimedop () Τȡ
.BR semtimedop ()

.I timeout
ǻꤵ줿»֤вᤷ: ΤȤ
.BR semtimedop ()
ϼԤ
.I errno

.B EAGAIN
ꤵ롣
.PP
硢
.I sops
ؤˤäоݤȤʤäƥޥե
.I sempid
СˤϸƤӽФץΥץ ID ꤵ롣

.I sem_otime
.\" 
.\" .I sem_ctime
˸߻郎ꤵ롣
.PP
.BR semtimedop ()
ؿο񤤤
.BR semop ()
Ʊ
ƤӽФץߤ硢ߴ֤ξ¤
.I timeout
λؤ
.I timespec
¤Τǻꤵ줿֤Ȥʤۤʤ롣
ꤷ»֤ãϡ
.BR semtimedop ()
ϼԤ
.I errno

.B EAGAIN
ꤵ
(ΤȤ
.I sops
ϼ¹Ԥʤ)
.I timeout
 NULL ξ硢
.BR semtimedop ()
ؿο񤤤
.BR semop ()
ؿƱˤʤ롣
.SH ֤
硢
.BR semop ()

.BR semtimedop ()
 0 ֤Ǥʤ \-1 ֤
顼򼨤
.I errno
ꤹ롣
.SH 顼
Ԥ硢
.I errno
˰ʲΤɤ줫ꤵ:
.TP
.B E2BIG
.I nsops

.B SEMOPM
礭
.B SEMOPM
ϰΥƥॳǵκĿǤ롣
.TP
.B EACCES
ƤӽФץˤϻꤵ줿ޥեԤΤ
ɬפʥĤʤ
.B CAP_IPC_OWNER
ѥӥƥʤ
.TP
.B EAGAIN
ľ˽뤳ȤǤ
.I sem_flg

.B IPC_NOWAIT
ꤵƤ뤫
.I timeout
ǻꤵ줿»֤вᤷ
.TP
.B EFAULT

.I sops

.I timeout
ؤƤ륢ɥ쥹˥Ǥʤ
.TP
.B EFBIG
ǡ
.I sem_num
ͤ 0 ̤ΥޥեοʾǤ롣
.TP
.B EIDRM
ޥե礬줿
.TP
.B EINTR
ΥƥॳߤƤ˥ץʥͤ
.BR single (7)
ȡ
.TP
.B EINVAL
ޥե礬¸ߤʤ
.I semid
 0 ̤Ǥ뤫
.I nsops
οǤʤ
.TP
.B ENOMEM

.I sem_flg

.B SEM_UNDO
ꤵ줿ƥ˥ɥ¤Τ˳Ƥ뽽ʬʥ꤬ʤ
.TP
.B ERANGE

.I sem_op+semval

.B SEMVMX
礭
.B SEMVMX

.I semval
κͤǡͤϼ¸Ǥ롣
.SH С
.BR semtimedop ()
 Linux 2.5.52 ǽо줷
줫饫ͥ 2.4.22 ˤܿ줿
.BR semtimedop ()
 glibc ǤΥݡȤϥС 2.3.3 ǽо줷
.SH 
SVr4, POSIX.1-2001.
.\" SVr4 ˤϡɲä EINVAL, EFBIG, ENOSPC Υ顼֤ˤĤƤ
.\" Ҥ롣
.SH 
ץ
.I sem_undo
¤Τ
.BR fork (2)
줿ҥץˤϷѾʤ
.BR execve (2)
ƥॳξϷѾ롣
.PP
.BR semop ()
ϥʥϥɥˤäǤ줿ˡ
褷ƼưŪ˺Ƴ뤳ȤϤʤ
Ȥʥϥɥ
.B SA_RESTART
ե饰åȤƤƤƳ뤳ȤϤʤ
.PP
.I semadj
ϥץȤǡ
.B SEM_UNDO
ե饰ꤷƼ¹Ԥ줿ƤΥޥե()󥿤Ǥ롣
.BR semctl (2)

.B SETVAL
ޤ
.B SETALL
ꤷޥեͤ
ľꤵ줿ˤϡƤΥץˤб
.I semadj
ͤꥢ롣
.PP
륻ޥե \fIsemval\fP, \fIsempid\fP, \fIsemzcnt\fP, \fIsemnct\fP
ͤϤ⡢Ŭڤꤷ
.BR semctl (2)
ƤӽФȤǼǤ롣
.PP
ޥեΥ꥽˴ؤ¤Τ
.BR semop ()
˱ƶڤܤΤʲ˵󤲤:
.TP
.B SEMOPM

.BR semop ()
ǵκ (32)
(Linux Ǥϡͤ
.I /proc/sys/kernel/sem
3եɤбɤ߽ФѹǤ)
.\"  /proc ե Linux 2.2 ǤѤǤʤ -- MTK
.TP
.B SEMVMX
.I semval
: ¸ (32767)
.PP
ʲͤ˴ؤƤϼ¸¤Ϥʤ
λĴ (adjust on exit) κ
.RB ( SEMAEM )
ƥΤΥɥ¤Τκ
.RB ( SEMMNU )
ץΥɥ¤Τκ
.SH Х
ץλݡץб
.I semadj
νȤäơ
.B SEM_UNDO
ե饰դǼ¹Ԥ줿ƤΥޥեαƶä
ˤꤢ꤬ȯ: ΥޥեĴԤäƤȡ
ˤϥޥեͤ 0 ̤ͤˤ褦Ȥ礬ФƤ롣
Τ褦ʾ硢ɤΤ褦˼٤?
ҤȤĤιͤˡϡƤΥޥեĴ¹Ԥޤ
ߤ뤳ȤǤ롣ˡǤϥץνλ
Ĺ֤ˤ錄äߤ뤳ȤΤ˾ޤʤ
ɤ줯餤Ĺ֤ˤʤ뤫ʬʤ
̤ȤơΤ褦ʥޥեĴ̵뤷Ƥޤˡ
(ϥޥեȤ
.B IPC_NOWAIT
ꤹΤȾƤ)
Linux 軰μˡѤƤ: ޥեͤ (Ĥޤ
0 ޤ) ơץνλľ³ԤǤ褦ˤƤ롣

ͥ 2.6.x (x <= 10) ˤϡˤƥޥեͤ 0 ˤʤΤ
ԤäƤץޥեͤºݤ 0 ˤʤäȤ˵ (wake up)
ʤȤХ롣ΥХϥͥ 2.6.11 ǽƤ롣
.\" Хݡ:
.\" http://marc.theaimsgroup.com/?l=linux-kernel&m=110260821123863&w=2
.\" :
.\" http://marc.theaimsgroup.com/?l=linux-kernel&m=110261701025794&w=2
.SH 
ʲʬŪʥɤϡ
ޥե 0 ͤ 0 ˤʤΤԤäƤ顢
ޥեͤ 1 û
.BR semop ()
Ȥäƥȥߥå (atomically) ˹Ԥ
.nf

    struct sembuf sops[2];
    int semid;

    /* Code to set \fIsemid\fP omitted */

    sops[0].sem_num = 0;        /* Operate on semaphore 0 */
    sops[0].sem_op = 0;         /* Wait for value to equal 0 */
    sops[0].sem_flg = 0;

    sops[1].sem_num = 0;        /* Operate on semaphore 0 */
    sops[1].sem_op = 1;         /* Increment value by one */
    sops[1].sem_flg = 0;

    if (semop(semid, sops, 2) == \-1) {
        perror("semop");
        exit(EXIT_FAILURE);
    }
.fi
.SH Ϣ
.BR semctl (2),
.BR semget (2),
.BR sigaction (2),
.BR capabilities (7),
.BR sem_overview (7),
.BR svipc (7),
.BR time (7)