[linuxjm/LDP_man-pages.git] / draft / man3 / lockf.3

.\" Copyright 1997 Nicolas Lichtmaier <nick@debian.org>
.\" Created Thu Aug  7 00:44:00 ART 1997
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License, or (at your option) any later version.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" Added section stuff, aeb, 2002-04-22.
.\" Corrected include file, drepper, 2003-06-15.
.\"
.\" Japanese Version Copyright (c) 2000-2002 Yuichi SATO
.\"         all rights reserved.
.\" Translated Tue Jul 11 19:02:58 JST 2000
.\"         by Yuichi SATO <ysato@h4.dion.ne.jp>
.\" Updated & Modified Mon Jul 15 02:10:29 JST 2002 by Yuichi SATO
.\" Updated 2010-04-18, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>, LDP v3.24
.\"
.\"WORD:        apply           ŬÍÑ
.\"WORD:        remove          ²ò½ü
.\"WORD:        exclusive       ÇÓ¾
.\"WORD:        descriptor      ¥Ç¥£¥¹¥¯¥ê¥×¥¿
.\"WORD:        
.\"
.TH LOCKF 3 2010-09-20 "GNU" "Linux Programmer's Manual"
.\"O .SH NAME
.SH ̾Á°
.\"O lockf \- apply, test or remove a POSIX lock on an open file
lockf \- ¥ª¡¼¥×¥ó¤µ¤ì¤¿¥Õ¥¡¥¤¥ë¤ËÂФ¹¤ë POSIX ¥í¥Ã¥¯¤ÎŬÍÑ¡¦¥Æ¥¹¥È¡¦²ò½ü¤ò¹Ô¤¦
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.B #include <unistd.h>
.sp
.BI "int lockf(int " fd ", int " cmd ", off_t " len );
.sp
.in -4n
.\"O Feature Test Macro Requirements for glibc (see
.\"O .BR feature_test_macros (7)):
glibc ¸þ¤±¤Îµ¡Ç½¸¡ºº¥Þ¥¯¥í¤ÎÍ×·ï
.RB ( feature_test_macros (7)
»²¾È):
.in
.sp
.BR lockf ():
.ad l
.RS 4
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 ||
_XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
.RE
.ad
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O Apply, test or remove a POSIX lock on a section of an open file.
¥ª¡¼¥×¥ó¤µ¤ì¤¿¥Õ¥¡¥¤¥ë¤Î¥»¥¯¥·¥ç¥ó¤ËÂФ·¤Æ¡¢
POSIX ¥í¥Ã¥¯¤ÎŬÍÑ¡¦¥Æ¥¹¥È¡¦²ò½ü¤ò¤¹¤ë¡£
.\"O The file is specified by
.\"O .IR fd ,
.\"O a file descriptor open for writing, the action by
.\"O .IR cmd ,
¥Õ¥¡¥¤¥ë¤Ï
.I fd
¤Ç»ØÄꤵ¤ì¤ë¡£
.I fd
¤Ï½ñ¤­¹þ¤ß¤Î¤¿¤á¤Ë¥ª¡¼¥×¥ó¤·¤¿¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤Ç¤¢¤ë¡£
¥¢¥¯¥·¥ç¥ó¤Ï
.I cmd
¤Ç»ØÄꤵ¤ì¤ë¡£
.\"O and the section consists of byte positions
.\"O .IR pos .. pos + len \-1
.\"O if
.\"O .I len
.\"O is positive, and
.\"O .IR pos - len .. pos \-1
.\"O if
.\"O .I len
.\"O is negative, where
.\"O .I pos
.\"O is the current file position, and if
.I pos
¤ò¸½ºß¤Î¥Õ¥¡¥¤¥ë°ÌÃ֤Ȥ¹¤ë¤È¡¢
.I len
¤¬Àµ¤Î¾ì¹ç¡¢¥»¥¯¥·¥ç¥ó¤Ï¥Ð¥¤¥È°ÌÃÖ
.IR pos .. pos + len \-1
¤È¤Ê¤ê¡¢
.I len
¤¬Éé¤Î¾ì¹ç¡¢¥»¥¯¥·¥ç¥ó¤Ï¥Ð¥¤¥È°ÌÃÖ
.IR pos - len .. pos \-1
¤È¤Ê¤ë¡£
.\"O .I len
.\"O is zero, the section extends from the current file position to
.\"O infinity, encompassing the present and future end-of-file positions.
.I len
¤¬ 0 ¤Î¾ì¹ç¡¢¥»¥¯¥·¥ç¥ó¤Ï¸½ºß¤Î¥Õ¥¡¥¤¥ë°ÌÃÖ¤«¤é̵¸ÂÂç¤Þ¤Ç¤È¤Ê¤ë
(¤Ä¤Þ¤ê¸½ºß¤Î¡¢¤¢¤ë¤¤¤ÏÊѹ¹¤µ¤ì¤¿¾ì¹ç¤Ï¾­Íè¤Î¡¢¥Õ¥¡¥¤¥ë½ªÃ¼°ÌÃÖ¤Þ¤Ç)¡£
.\"O In all cases, the section may extend past current end-of-file.
¤É¤Î¾ì¹ç¤Ë¤ª¤¤¤Æ¤â¡¢¥»¥¯¥·¥ç¥ó¤Ï°ÊÁ°¤Î¥Õ¥¡¥¤¥ë½ªÃ¼¤è¤ê¤â³ÈÂ礵¤ì¤¦¤ë¡£
.LP
.\"O On Linux,
.\"O .BR lockf ()
.\"O is just an interface on top of
.\"O .BR fcntl (2)
.\"O locking.
Linux ¤Ç¤Ï¡¢
.BR lockf ()
¤Ïñ¤Ë
.BR fcntl (2)
¤Î¥í¥Ã¥¯¤Ø¤Î¥¤¥ó¥¿¡¼¥Õ¥§¡¼¥¹¤Ç¤¢¤ë¡£
.\"O Many other systems implement
.\"O .BR lockf ()
.\"O in this way, but note that POSIX.1-2001 leaves the relationship between
.\"O .BR lockf ()
.\"O and
.\"O .BR fcntl (2)
.\"O locks unspecified.
.\"O A portable application should probably avoid mixing calls
.\"O to these interfaces.
¿¤¯¤Î¾¤Î¥·¥¹¥Æ¥à¤Ç
.BR lockf ()
¤Ï¤³¤Î¤è¤¦¤Ë¼ÂÁõ¤µ¤ì¤Æ¤¤¤ë¤¬¡¢
POSIX.1-2001 ¤Ç¤Ï
.BR lockf ()
¤È
.BR fcntl (2)
¤Î¥í¥Ã¥¯¤È¤Î´Ø·¸¤Ïµ¬Äꤵ¤ì¤Æ¤¤¤Ê¤¤¡£
¤ª¤½¤é¤¯¡¢°Ü¿¢À­¤¬É¬Íפʥ¢¥×¥ê¥±¡¼¥·¥ç¥ó¤Ç¤Ï¡¢
.BR lockf ()
¤È
.BR fcntl (2)
¤Î¥í¥Ã¥¯¤òº®¤¼¤Æ¸Æ¤Ó½Ð¤¹¤Î¤ÏÈò¤±¤ë¤Ù¤­¤Ç¤¢¤í¤¦¡£
.LP
.\"O Valid operations are given below:
Í­¸ú¤Ê¥ª¥×¥·¥ç¥ó¤ò°Ê²¼¤Ëµó¤²¤ë¡£
.TP
.B F_LOCK
.\"O Set an exclusive lock on the specified section of the file.
.\"O If (part of) this section is already locked, the call
.\"O blocks until the previous lock is released.
¥Õ¥¡¥¤¥ë¤Î»ØÄꤵ¤ì¤¿¥»¥¯¥·¥ç¥ó¤ËÇÓ¾¥í¥Ã¥¯¤òÀßÄꤹ¤ë¡£
¤½¤Î¥»¥¯¥·¥ç¥ó (¤Î°ìÉô) ¤¬´û¤Ë¥í¥Ã¥¯¤µ¤ì¤Æ¤¤¤¿¾ì¹ç¡¢
Á°¤Î¥í¥Ã¥¯¤¬²ò½ü¤µ¤ì¤ë¤Þ¤Ç´Ø¿ô¤Î¸Æ¤Ó½Ð¤·¤¬¥Ö¥í¥Ã¥¯¤µ¤ì¤ë¡£
.\"O If this section overlaps an earlier locked section,
.\"O both are merged.
¤³¤Î¥»¥¯¥·¥ç¥ó¤¬Á°¤Ë¥í¥Ã¥¯¤µ¤ì¤Æ¤¤¤ë¥»¥¯¥·¥ç¥ó¤È½Å¤Ê¤Ã¤¿¾ì¹ç¡¢
2 ¤Ä¤Î¥»¥¯¥·¥ç¥ó¤Ï·ë¹ç¤µ¤ì¤ë¡£
.\"O File locks are released as soon as the process holding the locks
.\"O closes some file descriptor for the file.
.\"O A child process does not
.\"O inherit these locks.
¥í¥Ã¥¯¤òÊÝ»ý¤·¤Æ¤¤¤ë¥×¥í¥»¥¹¤¬¡¢
¤½¤Î¥Õ¥¡¥¤¥ë¤Î¥Õ¥¡¥¤¥ë¥Ç¥£¥¹¥¯¥ê¥×¥¿¤ò¥¯¥í¡¼¥º¤¹¤ë¤È¡¢
¥Õ¥¡¥¤¥ë¥í¥Ã¥¯¤Ï²òÊü¤µ¤ì¤ë¡£
»Ò¥×¥í¥»¥¹¤Ï¥í¥Ã¥¯¤ò·Ñ¾µ¤·¤Ê¤¤¡£
.TP
.B F_TLOCK
.\"O Same as
.\"O .B F_LOCK
.\"O but the call never blocks and returns an error instead if the file is
.\"O already locked.
.B F_LOCK
¤ÈƱÍͤǤ¢¤ë¤¬¡¢¥Õ¥¡¥¤¥ë¤¬´û¤Ë¥í¥Ã¥¯¤µ¤ì¤Æ¤¤¤ë¾ì¹ç¡¢
´Ø¿ô¤Î¸Æ¤Ó½Ð¤·¤Ï¥Ö¥í¥Ã¥¯¤ò¹Ô¤ï¤º¤Ë¥¨¥é¡¼¤òÊÖ¤¹¡£
.TP
.B F_ULOCK
.\"O Unlock the indicated section of the file.
.\"O This may cause a locked section to be split into two locked sections.
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.TP
.B F_TEST
.\"O Test the lock: return 0 if the specified section
.\"O is unlocked or locked by this process; return \-1, set
.\"O .I errno
.\"O to
.\"O .B EAGAIN
.\"O .RB ( EACCES
.\"O on some other systems),
.\"O if another process holds a lock.
¼¡¤Î¤è¤¦¤Ë¥í¥Ã¥¯¤Î¥Æ¥¹¥È¤ò¤¹¤ë¡£
»ØÄꤵ¤ì¤¿¥»¥¯¥·¥ç¥ó¤¬¥í¥Ã¥¯¤µ¤ì¤Æ¤¤¤Ê¤¤¤«¡¢
¤³¤Î¥×¥í¥»¥¹¤Ë¤è¤ê¥í¥Ã¥¯¤µ¤ì¤Æ¤¤¤ë¾ì¹ç¡¢0 ¤òÊÖ¤¹¡£
¾¤Î¥×¥í¥»¥¹¤¬¥í¥Ã¥¯¤òÊÝ»ý¤·¤Æ¤¤¤ë¾ì¹ç¡¢\-1 ¤òÊÖ¤·¡¢
.I errno
¤ò
.B EAGAIN
(¤¤¤¯¤Ä¤«¤Î¾¤Î¥·¥¹¥Æ¥à¤Ç¤Ï
.BR EACCES )
¤ËÀßÄꤹ¤ë¡£
.\"O .SH "RETURN VALUE"
.SH ÊÖ¤êÃÍ
.\"O On success, zero is returned.
.\"O On error, \-1 is returned, and
.\"O .I errno
.\"O is set appropriately.
À®¸ù¤·¤¿¾ì¹ç¡¢0 ¤¬ÊÖ¤µ¤ì¤ë¡£
¥¨¥é¡¼¤Î¾ì¹ç¡¢\-1 ¤¬ÊÖ¤µ¤ì¡¢
.I errno
¤¬¥¨¥é¡¼¤ËÂбþ¤·¤¿ÃͤËÀßÄꤵ¤ì¤ë¡£
.\"O .SH ERRORS
.SH ¥¨¥é¡¼
.TP
.\"O .BR EACCES " or " EAGAIN
.BR EACCES " ¤â¤·¤¯¤Ï " EAGAIN
.\"O The file is locked and
.\"O .B F_TLOCK
.\"O or
.\"O .B F_TEST
.\"O was specified, or the operation is prohibited because the file has
.\"O been memory-mapped by another process.
¥í¥Ã¥¯¤µ¤ì¤¿¥Õ¥¡¥¤¥ë¤ËÂФ·¤Æ¡¢
.B F_TLOCK
¤Þ¤¿¤Ï
.B F_TEST
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»ØÄꤵ¤ì¤¿Áàºî¤¬¶Ø»ß¤µ¤ì¤Æ¤¤¤ë¡£
.TP
.B EBADF
.\"O .I fd
.\"O is not an open file descriptor.
.I fd
¤¬¥ª¡¼¥×¥ó¤µ¤ì¤¿¥Õ¥¡¥¤¥ë¤Î¥Ç¥£¥¹¥¯¥ê¥×¥¿¤Ç¤Ï¤Ê¤¤¡£
.TP
.B EDEADLK
.\"O The command was
.\"O .B T_LOCK
.\"O and this lock operation would cause a deadlock.
¥³¥Þ¥ó¥É¤¬
.B T_LOCK
¤Ç¤¢¤ê¡¢¤³¤Î¥í¥Ã¥¯Áàºî¤ò¹Ô¤¦¤È¥Ç¥Ã¥É¥í¥Ã¥¯¤¬È¯À¸¤·¤Æ¤·¤Þ¤¦¡£
.TP
.B EINVAL
.\"O An invalid operation was specified in
.\"O .IR fd .
.I fd
¤Ë̵¸ú¤ÊÁàºî¤¬»ØÄꤵ¤ì¤¿¡£
.TP
.B ENOLCK
.\"O Too many segment locks open, lock table is full.
Èó¾ï¤Ë¿¤¯¤Î¥»¥°¥á¥ó¥È¥í¥Ã¥¯¤¬³«¤«¤ì¡¢¥í¥Ã¥¯¥Æ¡¼¥Ö¥ë¤¬°ìÇդǤ¢¤ë¡£
.\"O .SH CONFORMING TO
.SH ½àµò
SVr4, POSIX.1-2001.
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.\"O .BR fcntl (2),
.\"O .BR flock (2)
.\"O .br
.\"O There are also
.\"O .I locks.txt
.\"O and
.\"O .I mandatory-locking.txt
.\"O in the kernel source directory
.\"O .IR Documentation/filesystems .
.\"O (On older kernels, these files are directly under the
.\"O .I Documentation/
.\"O directory, and
.\"O .I mandatory-locking.txt
.\"O is called
.\"O .IR mandatory.txt .)
.BR fcntl (2),
.BR flock (2)
.br
¥«¡¼¥Í¥ë¥½¡¼¥¹¤Î
.I Documentation/filesystems
¥Ç¥£¥ì¥¯¥È¥ê¤Ë¤¢¤ë
.I locks.txt
¤È
.I mandatory-locking.txt
(°ÊÁ°¤Î¥«¡¼¥Í¥ë¤Ç¤Ï¡¢¤³¤ì¤é¤Î¥Õ¥¡¥¤¥ë¤Ï
.I Documentation
¥Ç¥£¥ì¥¯¥È¥êľ²¼¤Ë¤¢¤ê¡¢
.I mandatory-locking.txt
¤Ï
.I mandatory.txt
¤È¤¤¤¦Ì¾Á°¤Ç¤¢¤Ã¤¿¡£)