(split) Apply minor changes from v3.32 to v3.35 in the upstream.

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

.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
.\" 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.\" manual page may be incorrect or out-of-date.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.
.\"
.\" References consulted:
.\"     Linux libc source code
.\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
.\"     386BSD man pages
.\" Modified Sun Jul 25 11:01:58 1993 by Rik Faith (faith@cs.unc.edu)
.\" Modified 2001-11-13, aeb
.\" Modified 2004-12-01 mtk and Martin Schulze <joey@infodrom.org>
.\"
.\" Japanese Version Copyright (c) 1998 NAKANO Takeo all rights reserved.
.\" Translated 1998-03-23, NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\" Updated 2000-09-14, Kentaro Shirakata <argrath@ub32.org>
.\" Updated 2002-01-06, NAKANO Takeo
.\" Updated 2007-01-07, Akihiro MOTOKI, catch up to LDP v2.43
.\"
.\" WORD:       Wall Clock Time                 ÊÉ»þ·×»þ¹ï
.\" WORD:       Coordinated Universal Time      ¶¨ÄêÀ¤³¦»þ
.\" WORD:       daylight saving time            ¥µ¥Þ¡¼¥¿¥¤¥à
.\" WORD:       Prime Meridian                  ¥°¥ê¥Ë¥Ã¥¸»Ò¸áÀþ
.\"
.TH TZSET 3  2010-02-25 "" "Linux Programmer's Manual"
.\"O .SH NAME
.\"O tzset, tzname, timezone, daylight \- initialize time conversion information
.SH ̾Á°
tzset, tzname, timezone, daylight \- »þ¹ï¤ÎÊÑ´¹¾ðÊó¤ò½é´ü²½¤¹¤ë
.\"O .SH SYNOPSIS
.SH ½ñ¼°
.nf
.B #include <time.h>
.sp
.B void tzset (void);
.sp
.BI "extern char *" tzname [2];
.BI "extern long " timezone ;
.BI "extern int " daylight ;
.fi
.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 tzset ():
_POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _POSIX_SOURCE
.br
.IR tzname :
_POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _POSIX_SOURCE
.br
.IR timezone :
_SVID_SOURCE || _XOPEN_SOURCE
.br
.IR daylight :
_SVID_SOURCE || _XOPEN_SOURCE
.\"O .SH DESCRIPTION
.SH ÀâÌÀ
.\"O The
.\"O .BR tzset ()
.\"O function initializes the \fItzname\fP variable from the
.\"O .B TZ
.\"O environment variable.
.\"O This function is automatically called by the
.\"O other time conversion functions that depend on the timezone.
.\"O In a System-V-like environment, it will also set the variables \fItimezone\fP
.\"O (seconds West of UTC) and \fIdaylight\fP (to 0 if this timezone does not
.\"O have any daylight saving time rules, or to nonzero if there is a time during
.\"O the year when daylight saving time applies).
.BR tzset ()
´Ø¿ô¤Ï
.B TZ
´Ä¶­ÊÑ¿ô¤òÍѤ¤¤Æ \fItzname\fP ÊÑ¿ô¤ò½é´ü²½¤¹¤ë¡£
¤³¤Î´Ø¿ô¤Ï¡¢¥¿¥¤¥à¥¾¡¼¥ó¤Ë°Í¸¤¹¤ë¾¤Î»þ¹ïÊÑ´¹´Ø¿ô¤«¤é¼«Æ°Åª¤Ë¸Æ¤Ó½Ð¤µ¤ì¤ë¡£
System V Ū¤Ê´Ä¶­¤Ç¤Ï¡¢¤³¤Î´Ø¿ô¤ÏÊÑ¿ô \fItimezone\fP (UTC ¤«¤é¤ÎÀ¾¸þ¤­¤ÎÉÿô) ¤È
\fIdaylight\fP (¤³¤Î¥¿¥¤¥à¥¾¡¼¥ó¤Ë¥µ¥Þ¡¼¥¿¥¤¥à¤Ë´Ø¤¹¤ë¥ë¡¼¥ë¤¬¤Ê¤±¤ì¤Ð 0¡¢
¥µ¥Þ¡¼¥¿¥¤¥à´ü´Ö¤¬°ìǯ¤Î¤É¤³¤«¤Ë¤¢¤ì¤Ð 0 °Ê³°) ¤âÀßÄꤹ¤ë¡£
.PP
.\"O If the
.\"O .B TZ
.\"O variable does not appear in the environment, the \fItzname\fP
.\"O variable is initialized with the best approximation of local wall clock
.\"O time, as specified by the
.\"O .BR tzfile (5)-format
.\"O file \fIlocaltime\fP
.\"O found in the system timezone directory (see below).
.B TZ
´Ä¶­ÊÑ¿ô¤¬ÀßÄꤵ¤ì¤Æ¤¤¤Ê¤¤¾ì¹ç¤Ë¤Ï¡¢
\fItzname\fP ÊÑ¿ô¤Ï¥í¡¼¥«¥ë¤ÊÊÉ»þ·×»þ¹ï (wall clock time) ¤Ë
ºÇ¤â¶á¤¤Ãͤ˽é´ü²½¤µ¤ì¤ë¡£
¤³¤Î¥í¡¼¥«¥ë¤ÊÊÉ»þ·×»þ¹ï¤È¤·¤Æ¤Ï¡¢
¥·¥¹¥Æ¥à¤Î¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê (¸å½Ò) ¤Ë¤¢¤ë
.BR tzfile (5)
·Á¼°¤Î¥Õ¥¡¥¤¥ë \fIlocaltime\fP ¤Ç»ØÄꤵ¤ì¤Æ¤¤¤ëÃͤ¬ÍѤ¤¤é¤ì¤ë¡£
.\"O (One also often sees
.\"O .I /etc/localtime
.\"O used here, a symlink to the right file in the system timezone directory.)
(¤³¤ÎºÝ¤Ë¤Ï
.I /etc/localtime
¤â¤è¤¯ÍѤ¤¤é¤ì¤ë¡£
¤³¤ì¤Ï¥·¥¹¥Æ¥à¤Î¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤Ë¤¢¤ë
ŬÀڤʥե¡¥¤¥ë¤Ø¤Î¥·¥ó¥Ü¥ê¥Ã¥¯¥ê¥ó¥¯¤Ë¤Ê¤Ã¤Æ¤¤¤ë¡£)
.PP
.\"O If the
.\"O .B TZ
.\"O variable does appear in the environment but its value is empty
.\"O or its value cannot be interpreted using any of the formats specified
.\"O below, Coordinated Universal Time (UTC) is used.
.B TZ
´Ä¶­ÊÑ¿ô¤¬Â¸ºß¤·¤Æ¤¤¤ë¤¬¡¢¤½¤ÎÃͤ¬¶õ¤À¤Ã¤¿¤ê¡¢
°Ê²¼¤Ë¼¨¤¹·Á¼°¤Î¤É¤ì¤Ë¤â¤¢¤Æ¤Ï¤Þ¤é¤Ê¤¤¾ì¹ç¤Ï¡¢
¶¨ÄêÀ¤³¦»þ (Coordinated Universal Time: UTC) ¤¬ÍѤ¤¤é¤ì¤ë¡£
.PP
.\"O The value of
.\"O .B TZ
.\"O can be one of three formats.
.\"O The first format is used
.\"O when there is no daylight saving time in the local timezone:
.B TZ
¤ÎÃͤϰʲ¼¤Î 3 ¤Ä¤Î·Á¼°¤Î¤¤¤º¤ì¤«¤ò¼è¤ë¤³¤È¤¬¤Ç¤­¤ë¡£
ºÇ½é¤Î·Á¼°¤Ï¥µ¥Þ¡¼¥¿¥¤¥à (daylight saving time)
¤ò»ý¤¿¤Ê¤¤¥í¡¼¥«¥ë¥¿¥¤¥à¥¾¡¼¥ó¤ËÂФ·¤ÆÍѤ¤¤ë¡£
.sp
.RS
.I std offset
.RE
.sp
.\"O The \fIstd\fP string specifies the name of the timezone and must be
.\"O three or more alphabetic characters.
.\"O The \fIoffset\fP string immediately
.\"O follows \fIstd\fP and specifies the time value to be added to the local
.\"O time to get Coordinated Universal Time (UTC).
.\"O The \fIoffset\fP is positive
.\"O if the local timezone is west of the Prime Meridian and negative if it is
.\"O east.
.\"O The hour must be between 0 and 24, and the minutes and seconds
.\"O 0 and 59.
\fIstd\fP ʸ»úÎó¤Ï¥¿¥¤¥à¥¾¡¼¥ó¤Î̾Á°¤ò»ØÄꤹ¤ë¡£
¥¢¥ë¥Õ¥¡¥Ù¥Ã¥È¤«¤é¤Ê¤ë 3 ʸ»ú°Ê¾å¤Îʸ»úÎó¤Ç¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£
\fIoffset\fP ʸ»úÎó¤Ï \fIstd\fP ¤Îľ¸å¤Ë³¤­¡¢
¶¨ÄêÀ¤³¦»þ (UTC) ¤òÆÀ¤ë¤¿¤á¤Ë
¥í¡¼¥«¥ë¤Ê»þ¹ï¤Ë²Ã¤¨¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤»þ´Ö¤ò»ØÄꤹ¤ë¡£
.I offset
¤Ï¡¢¥í¡¼¥«¥ë¥¿¥¤¥à¥¾¡¼¥ó¤¬¥°¥ê¥Ë¥Ã¥¸»Ò¸áÀþ (Prime Meridian)
¤ÎÀ¾¤Ê¤éÀµ¤ÎÃÍ¡¢Åì¤Ê¤éÉé¤ÎÃͤò¼è¤ë¡£
»þ´Ö (hour) ¤Ï 0 ¤«¤é 24 ¤Î´Ö¤Ç¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£
ʬ (minute) ¤ÈÉà (second) ¤Ï 0 ¤«¤é 59 ¤Î´Ö¤Ç¤Ê¤±¤ì¤Ð¤Ê¤é¤Ê¤¤¡£
.PP
.\"O The second format is used when there is daylight saving time:
2 ÈÖÌܤηÁ¼°¤Ï¥µ¥Þ¡¼¥¿¥¤¥à¤¬¤¢¤ë¾ì¹ç¤ËÍѤ¤¤é¤ì¤ë¡£
.sp
.RS
.I std offset dst [offset],start[/time],end[/time]
.RE
.sp
.\"O There are no spaces in the specification.
.\"O The initial \fIstd\fP and
.\"O \fIoffset\fP specify the standard timezone, as described above.
.\"O The \fIdst\fP string and \fIoffset\fP specify the name and offset for the
.\"O corresponding daylight saving timezone.
.\"O If the offset is omitted,
.\"O it default to one hour ahead of standard time.
»ØÄê¤Ë¤Ï¥¹¥Ú¡¼¥¹¤ò´Þ¤á¤Æ¤Ï¤Ê¤é¤Ê¤¤¡£
ÀèƬ¤Î \fIstd\fP ¤È \fIoffset\fP ¤Ï 1 ÈÖÌܤηÁ¼°¤ÈƱ¤¸¤Ç¡¢
ɸ½à¤Î¥¿¥¤¥à¥¾¡¼¥ó¤ò»ØÄꤹ¤ë¡£
\fIdst\fP ʸ»úÎó¤È \fIoffset\fP ¤Ï¡¢
Âбþ¤¹¤ë¥µ¥Þ¡¼¥¿¥¤¥à¥¾¡¼¥ó¤Î̾Á°¤È¥ª¥Õ¥»¥Ã¥È¤ò»ØÄꤹ¤ë¡£
¥ª¥Õ¥»¥Ã¥È¤¬¾Êά¤µ¤ì¤ë¤È¡¢¥Ç¥Õ¥©¥ë¥È¤Ç¤Ïɸ½à¤Î°ì»þ´ÖÁ°¤È¤Ê¤ë¡£
.PP
.\"O The \fIstart\fP field specifies when daylight saving time goes into
.\"O effect and the \fIend\fP field specifies when the change is made back to
.\"O standard time.
.\"O These fields may have the following formats:
\fIstart\fP ¥Õ¥£¡¼¥ë¥É¤Ï¥µ¥Þ¡¼¥¿¥¤¥à¤¬Í­¸ú¤Ë¤Ê¤ë»þ¹ï¡¢
\fIend\fP ¥Õ¥£¡¼¥ë¥É¤Ïɸ½à¤ËÌá¤ë»þ¹ï¤Ç¤¢¤ë¡£
¤³¤ì¤é¤Î¥Õ¥£¡¼¥ë¥É¤Ï°Ê²¼¤Î·Á¼°¤Ç»ØÄꤹ¤ë¡£
.TP
J\fIn\fP
.\"O This specifies the Julian day with \fIn\fP between 1 and 365.
.\"O February 29 is never counted even in leap years.
ǯ¤ÎÄÌÆü (Julian day) ¤ÇÆü¤Ë¤Á¤ò»ØÄꤹ¤ë¡£
\fIn\fP ¤Ï 1 ¤«¤é 365 ¤Î´Ö¤Î¿ôÃÍ¡£
¤¦¤ë¤¦Ç¯¤Î¾ì¹ç¤Ç¤â 2 ·î 29 Æü¤Ï¥«¥¦¥ó¥È¤µ¤ì¤Ê¤¤¡£
.TP
.I n
.\"O This specifies the Julian day with \fIn\fP between 1 and 365.
.\"O February 29 is counted in leap years.
ǯ¤ÎÄÌÆü¤ÇÆü¤Ë¤Á¤ò»ØÄꤹ¤ë¡£
\fIn\fP ¤Ï 1 ¤«¤é 365 ¤Î´Ö¤Î¿ôÃÍ¡£
¤¦¤ë¤¦Ç¯¤Î¾ì¹ç¤Ë¤Ï 2 ·î 29 Æü¤¬¥«¥¦¥ó¥È¤µ¤ì¤ë¡£
.TP
M\fIm\fP.\fIw\fP.\fId\fP
.\"O This specifies day \fId\fP (0 <= \fId\fP <= 6) of week \fIw\fP
.\"O (1 <= \fIw\fP <= 5) of month \fIm\fP (1 <= \fIm\fP <= 12).
.\"O Week 1 is
.\"O the first week in which day \fId\fP occurs and week 5 is the last week
.\"O in which day \fId\fP occurs.
.\"O Day 0 is a Sunday.
\fIm\fP ¤Ï·î (1 <= \fIm\fP <= 12) ¤ò¡¢
\fIw\fP ¤Ï·î¤Î¤¦¤Á¤Î½µ (1 <= \fIw\fP <= 5) ¤ò¡¢
\fId\fP ¤Ï½µ¤Î¤¦¤Á¤ÎÆü¤Ë¤Á (0 <= \fId\fP <= 6) ¤ò¼¨¤¹¡£
\fIw\fP = 1 ¤Ï½ê°¤¹¤ë \fId\fP ¤¬Â¸ºß¤¹¤ëºÇ½é¤Î½µ¡¢
\fIw\fP = 5 ¤ÏºÇ¸å¤Î½µ¤Ç¤¢¤ë¡£
\fId\fP = 0 ¤ÏÆüÍËÆü¤Ç¤¢¤ë¡£
.PP
.\"O The \fItime\fP fields specify when, in the local time currently in effect,
.\"O the change to the other time occurs.
.\"O If omitted, the default is 02:00:00.
\fItime\fP ¥Õ¥£¡¼¥ë¥É¤Ï¡¢¥í¡¼¥«¥ë¥¿¥¤¥à¤òÀÚ¤êÂؤ¨¤ë»þ¹ï¤ò¡¢
Êѹ¹Á°¤Î¥í¡¼¥«¥ë¥¿¥¤¥à¤Çɽ¤·¤¿¤â¤Î¤Ç¤¢¤ë¡£
¾Êά¤µ¤ì¤¿¾ì¹ç¤Î¥Ç¥Õ¥©¥ë¥È¤Ï 02:00:00 ¤Ç¤¢¤ë¡£

.\"O Here is an example for New Zealand,
.\"O where the standard time (NZST) is 12 hours ahead of UTC,
.\"O and daylight saving time (NZDT), 13 hours ahead of UTC,
.\"O runs from the first Sunday in October to the third Sunday in March,
.\"O and the changeovers happen at the default time of 02:00:00:
¥Ë¥å¡¼¥¸¡¼¥é¥ó¥É¤ÎÎã¤Ç¤¢¤ë¡£
¥Ë¥å¡¼¥¸¡¼¥é¥ó¥É¤Ç¤Ï¡¢É¸½à¤Î¥¿¥¤¥à¥¾¡¼¥ó (NZST) ¤Ï UTC ¤è¤ê 12»þ´Ö¿Ê¤ó¤Ç¤ª¤ê¡¢
¥µ¥Þ¡¼¥¿¥¤¥à (NZDT) ¤Ï UTC ¤Î 13»þ´Ö¿Ê¤ó¤Ç¤¤¤ë¡£
¥µ¥Þ¡¼¥¿¥¤¥à¤Ï 10·î¤ÎÂè°ìÆüÍˤ«¤é 3·î¤ÎÂè»°ÆüÍˤޤǤǤ¢¤ê¡¢
¥í¡¼¥«¥ë¥¿¥¤¥à¤ÎÀÚ¤êÂؤ¨¤Ï¥Ç¥Õ¥©¥ë¥È¤Î 02:00:00 ¤Ë¹Ô¤ï¤ì¤ë¡£
.nf

    TZ="NZST-12:00:00NZDT-13:00:00,M10.1.0,M3.3.0"
.fi
.PP
.\"O The third format specifies that the timezone information should be read
.\"O from a file:
3 ÈÖÌܤηÁ¼°¤Ï¡¢¥¿¥¤¥à¥¾¡¼¥ó¤Î¾ðÊó¤ò¥Õ¥¡¥¤¥ë¤«¤éÆɤ߹þ¤à¤è¤¦¤Ë»ØÄꤹ¤ë¡£
.sp
.RS
:[filespec]
.RE
.sp
.\"O If the file specification \fIfilespec\fP is omitted, the timezone
.\"O information is read from the file
.\"O .I localtime
.\"O in the system timezone directory, which nowadays usually is
.\"O .IR /usr/share/zoneinfo .
¥Õ¥¡¥¤¥ë¤Î»ØÄê \fIfilespec\fP ¤¬¾Êά¤µ¤ì¤¿¾ì¹ç¤Ï¡¢
¥¿¥¤¥à¥¾¡¼¥ó¤Î¾ðÊó¤Ï¥·¥¹¥Æ¥à¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤Î
.I localtime
¥Õ¥¡¥¤¥ë¤«¤éÆɤޤì¤ë¡£
ºÇ¶á¤Ç¤Ï¥·¥¹¥Æ¥à¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤ÏÉáÄÌ
.I /usr/share/zoneinfo/localtime
¤Ç¤¢¤ë¡£
.\"O This file is in
.\"O .BR tzfile (5)
.\"O format.
.\"O If \fIfilespec\fP is given, it specifies another
.\"O .BR tzfile (5)-format
.\"O file to read the timezone information from.
.\"O If \fIfilespec\fP does not begin with a \(aq/\(aq, the file specification is
.\"O relative to the system timezone directory.
¤³¤Î¥Õ¥¡¥¤¥ë¤Ï
.BR tzfile (5)
·Á¼°¤Ç½ñ¤«¤ì¤Æ¤¤¤ë¡£
\fIfilespec\fP ¤¬Í¿¤¨¤é¤ì¤¿¾ì¹ç¤Ï¡¢
¥¿¥¤¥à¥¾¡¼¥ó¤Î¾ðÊó¤ò¤½¤Î¥Õ¥¡¥¤¥ë¤«¤éÆɤ߹þ¤à¡£¤³¤Î¥Õ¥¡¥¤¥ë¤â
.BR tzfile (5)
·Á¼°¤Ç½ñ¤«¤ì¤Æ¤¤¤ëɬÍפ¬¤¢¤ë¡£
\fIfilespec\fP ¤¬ \(aq/\(aq ¤Ç»Ï¤Þ¤é¤Ê¤«¤Ã¤¿¾ì¹ç¤Ë¤Ï¡¢
¥·¥¹¥Æ¥à¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤«¤é¤ÎÁêÂХѥ¹¤Ç
¥Õ¥¡¥¤¥ë¤¬»ØÄꤵ¤ì¤¿¤³¤È¤Ë¤Ê¤ë¡£
.PP
.\"O Here's an example, once more for New Zealand:
Îã¤òµó¤²¤Æ¤ª¤¯¡£¤â¤¦°ìÅ٥˥塼¥¸¡¼¥é¥ó¥É¤ÎÎã¤Ç¤¢¤ë¡£
.nf

    TZ=":Pacific/Auckland"
.fi
.\"O .SH FILES
.SH ¥Õ¥¡¥¤¥ë
.\"O The system timezone directory used depends on the (g)libc version.
ÍѤ¤¤é¤ì¤ë¥·¥¹¥Æ¥à¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤Ï (g)libc ¤Î¥Ð¡¼¥¸¥ç¥ó¤Ë°Í¸¤¹¤ë¡£
.\"O Libc4 and libc5 use
.\"O .IR /usr/lib/zoneinfo ,
.\"O and, since libc-5.4.6,
.\"O when this doesn't work, will try
.\"O .IR /usr/share/zoneinfo .
libc4 ¤È libc5 ¤Ï
.I /usr/lib/zoneinfo
¤òÍѤ¤¤ë¡£libc-5.4.6 °Ê¹ß¤Ç¤Ï¡¢¤³¤ì¤¬»È¤¨¤Ê¤«¤Ã¤¿¾ì¹ç¤Ë¤Ï
.I /usr/share/zoneinfo
¤ò»È¤ª¤¦¤È¤¹¤ë¡£
.\"O Glibc2 will use the environment variable
.\"O .BR TZDIR ,
.\"O when that exists.
glibc2 ¤Ç¤Ï´Ä¶­ÊÑ¿ô
.B TZDIR
¤¬Â¸ºß¤¹¤ì¤Ð¤½¤ì¤òÍѤ¤¤ë¡£
.\"O Its default depends on how it was installed, but normally is
.\"O .IR /usr/share/zoneinfo .
¤³¤Î¥Ç¥Õ¥©¥ë¥È¤Ï¤É¤Î¤è¤¦¤Ë¥¤¥ó¥¹¥È¡¼¥ë¤µ¤ì¤¿¤«¤Ë¤è¤ë¤¬¡¢
ÉáÄ̤Ï
.I /usr/share/zoneinfo
¤Ç¤¢¤ë¡£
.LP
.\"O This timezone directory contains the files
¤³¤Î¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤Ë¤Ï°Ê²¼¤Î¥Õ¥¡¥¤¥ë¤¬´Þ¤Þ¤ì¤ë¡£
.sp
.nf
.\"O localtime      local timezone file
.\"O posixrules     rules for POSIX-style TZ's
localtime      ¥í¡¼¥«¥ë¥¿¥¤¥à¥¾¡¼¥ó¤Î¥Õ¥¡¥¤¥ë
posixrules     POSIX ¼°¤Î TZ ½ñ¼°¥ë¡¼¥ë
.fi
.LP
.\"O Often
.\"O .I /etc/localtime
.\"O is a symlink to the file
.\"O .I localtime
.\"O or to the correct timezone file in the system timezone directory.
.I /etc/localtime
¤Ï¡¢
.I localtime
¥Õ¥¡¥¤¥ë¤ä¡¢
¥·¥¹¥Æ¥à¤Î¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥êÃæ¤ÎŬÀڤʥ¿¥¤¥à¥¾¡¼¥ó¥Õ¥¡¥¤¥ë¤Ø¤Î
¥·¥ó¥Ü¥ê¥Ã¥¯¥ê¥ó¥¯¤Ç¤¢¤ë¤³¤È¤¬Â¿¤¤¡£
.\"O .SH "CONFORMING TO"
.SH ½àµò
SVr4, POSIX.1-2001, 4.3BSD.
.\"O .SH NOTES
.SH Ãí°Õ
.\"O Note that the variable \fIdaylight\fP does not indicate that daylight
.\"O saving time applies right now.
.\"O It used to give the number of some
.\"O algorithm (see the variable \fItz_dsttime\fP in
.\"O .BR gettimeofday (2)).
.\"O It has been obsolete for many years but is required by SUSv2.
.I daylight
ÊÑ¿ô¤Ï¡¢¸½ºß¤¬¥µ¥Þ¡¼¥¿¥¤¥à¤Ç¤¢¤ë¤«¤É¤¦¤«¤ò¼¨¤·¤Æ¤¤¤ë¤Î¤Ç¤Ï¤Ê¤¤¡£
¤³¤ì¤Ï¤¤¤¯¤Ä¤«¤¢¤ë¥¢¥ë¥´¥ê¥º¥à¤Î¤¦¤Á¤ÎÈÖ¹æ¤òÍ¿¤¨¤ë
(¥¢¥ë¥´¥ê¥º¥à¤Ë¤Ä¤¤¤Æ¤Ï
.BR gettimeofday (2)
¤Î
.I tz_dsttime
ÊÑ¿ô¤ò¸«¤è)¡£
¤³¤ì¤Ï¤â¤¦²¿Ç¯¤â»È¤ï¤ì¤Æ¤¤¤Ê¤¤¤¬¡¢SUSv2 ¤Ç¤ÏɬÍפȤµ¤ì¤Æ¤¤¤ë¡£
.LP
.\"O 4.3BSD had a function
.\"O .BI "char *timezone(" zone ", " dst )
.\"O that returned the
.\"O name of the timezone corresponding to its first argument (minutes
.\"O West of UTC).
.\"O If the second argument was 0, the standard name was used,
.\"O otherwise the daylight saving time version.
4.3BSD ¤Ë¤Ï
.BI "char *timezone(" zone ", " dst )
¤È¤¤¤¦¥ë¡¼¥Á¥ó¤¬¤¢¤ê¡¢¤³¤ì¤Ï
ºÇ½é¤Î°ú¿ô (UTC ¤«¤é¤ÎÀ¾¸þ¤­¤Îʬ¿ô) ¤ËÂбþ¤¹¤ë¥¿¥¤¥à¥¾¡¼¥ó¤Î̾Á°¤òÊÖ¤¹¡£
ÆóÈÖÌܤΰú¿ô¤¬ 0 ¤Î¾ì¹ç¤Ïɸ½à¤Î̾Á°¤¬ÍѤ¤¤é¤ì¡¢
¤½¤ì°Ê³°¤Ï¥µ¥Þ¡¼¥¿¥¤¥àÈǤÎ̾Á°¤¬ÍѤ¤¤é¤ì¤ë¡£
.\"O .SH "SEE ALSO"
.SH ´ØÏ¢¹àÌÜ
.BR date (1),
.BR gettimeofday (2),
.BR time (2),
.BR ctime (3),
.BR getenv (3),
.BR tzfile (5)