Linux Certif

Toute la documentation sur la certification Linux LPI

tzset

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tzset, tzname, timezone, daylight - »þ¹ï¤ÎÊÑ´¹¾ðÊó¤ò½é´ü²½¤¹¤ë

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#include <time.h>



void tzset (void);



extern char *tzname[2];

extern long timezone;

extern int daylight;

ÀâÌÀ

tzset() ´Ø¿ô¤Ï TZ ´Ä¶­ÊÑ¿ô¤òÍѤ¤¤Æ tzname 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¡£ SysV Ū¤Ê´Ä¶­¤Ç¤Ï¡¢¤³¤Î´Ø¿ô¤ÏÊÑ¿ô timezone (GMT ¤«¤é¤ÎÀ¾¸þ¤­¤ÎÉÿô) ¤È daylight (¤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¡£

TZ ´Ä¶­ÊÑ¿ô¤¬ÀßÄꤵ¤ì¤Æ¤¤¤Ê¤¤¾ì¹ç¤Ë¤Ï¡¢ tzname 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 tzfile(5) ·Á¼°¤Î¥Õ¥¡¥¤¥ë localtime ¤Ç»ØÄꤵ¤ì¤Æ¤¤¤ëÃͤ¬ÍѤ¤¤é¤ì¤ë¡£ (¤³¤ÎºÝ¤Ë¤Ï /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¡£)

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¡£

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¡£

std offset

std 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¤¤¡£ offset ʸ»úÎó¤Ï std ¤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¡£ 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¤¤¡£

2 ÈÖÌܤηÁ¼°¤Ï¥µ¥Þ¡¼¥¿¥¤¥à¤¬¤¢¤ë¾ì¹ç¤ËÍѤ¤¤é¤ì¤ë¡£

std offset dst [offset],start[/time],end[/time]

»ØÄê¤Ë¤Ï¥¹¥Ú¡¼¥¹¤ò´Þ¤á¤Æ¤Ï¤Ê¤é¤Ê¤¤¡£ ÀèƬ¤Î std ¤È offset ¤Ï 1 ÈÖÌܤηÁ¼°¤ÈƱ¤¸¤Ç¡¢ ɸ½à¤Î¥¿¥¤¥à¥¾¡¼¥ó¤ò»ØÄꤹ¤ë¡£ dst ʸ»úÎó¤È offset ¤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¡£

start ¥Õ¥£¡¼¥ë¥É¤Ï¥µ¥Þ¡¼¥¿¥¤¥à¤¬Í­¸ú¤Ë¤Ê¤ë»þ¹ï¡¢ end ¥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¡£

Jn

ǯ¤ÎÄÌÆü (Julian day) ¤ÇÆü¤Ë¤Á¤ò»ØÄꤹ¤ë¡£ n ¤Ï 1 ¤«¤é 365 ¤Î´Ö¤Î¿ôÃÍ¡£ ¤¦¤ë¤¦Ç¯¤Î¾ì¹ç¤Ç¤â 2 ·î 29 Æü¤Ï¥«¥¦¥ó¥È¤µ¤ì¤Ê¤¤¡£

n

ǯ¤ÎÄÌÆü¤ÇÆü¤Ë¤Á¤ò»ØÄꤹ¤ë¡£ n ¤Ï 1 ¤«¤é 365 ¤Î´Ö¤Î¿ôÃÍ¡£ ¤¦¤ë¤¦Ç¯¤Î¾ì¹ç¤Ë¤Ï 2 ·î 29 Æü¤¬¥«¥¦¥ó¥È¤µ¤ì¤ë¡£

Mm.w.d

m ¤Ï·î (1 <= m <= 12) ¤ò¡¢ w ¤Ï·î¤Î¤¦¤Á¤Î½µ (1 <= w <= 5) ¤ò¡¢ d ¤Ï½µ¤Î¤¦¤Á¤ÎÆü¤Ë¤Á (0 <= d <= 6) ¤ò¼¨¤¹¡£ w = 1 ¤Ï½ê°¤¹¤ë d ¤¬Â¸ºß¤¹¤ëºÇ½é¤Î½µ¡¢ w = 5 ¤ÏºÇ¸å¤Î½µ¤Ç¤¢¤ë¡£ d = 0 ¤ÏÆüÍËÆü¤Ç¤¢¤ë¡£

time ¥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¡£

¥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¡£

    TZ="NZST-12.00:00NZDT-13:00:00,M10.1.0,M3.3.0"

3 ÈÖÌܤηÁ¼°¤Ï¡¢¥¿¥¤¥à¥¾¡¼¥ó¤Î¾ðÊó¤ò¥Õ¥¡¥¤¥ë¤«¤éÆɤ߹þ¤à¤è¤¦¤Ë»ØÄꤹ¤ë¡£

:[filespec]

¥Õ¥¡¥¤¥ë¤Î»ØÄê filespec ¤¬¾Êά¤µ¤ì¤¿¾ì¹ç¤Ï¡¢ ¥¿¥¤¥à¥¾¡¼¥ó¤Î¾ðÊó¤Ï¥·¥¹¥Æ¥à¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤Î localtime ¥Õ¥¡¥¤¥ë¤«¤éÆɤޤì¤ë¡£ ºÇ¶á¤Ç¤Ï¥·¥¹¥Æ¥à¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤ÏÉáÄÌ /usr/share/zoneinfo/localtime ¤Ç¤¢¤ë¡£ ¤³¤Î¥Õ¥¡¥¤¥ë¤Ï tzfile(5) ·Á¼°¤Ç½ñ¤«¤ì¤Æ¤¤¤ë¡£ filespec ¤¬Í¿¤¨¤é¤ì¤¿¾ì¹ç¤Ï¡¢ ¥¿¥¤¥à¥¾¡¼¥ó¤Î¾ðÊó¤ò¤½¤Î¥Õ¥¡¥¤¥ë¤«¤éÆɤ߹þ¤à¡£¤³¤Î¥Õ¥¡¥¤¥ë¤â tzfile(5) ·Á¼°¤Ç½ñ¤«¤ì¤Æ¤¤¤ëɬÍפ¬¤¢¤ë¡£ filespec ¤¬ `/' ¤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¡£

Îã¤òµó¤²¤Æ¤ª¤¯¡£¤â¤¦°ìÅ٥˥塼¥¸¡¼¥é¥ó¥É¤ÎÎã¤Ç¤¢¤ë¡£

    TZ=":Pacific/Auckland"

¥Õ¥¡¥¤¥ë

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¡£ libc4 ¤È libc5 ¤Ï /usr/lib/zoneinfo ¤òÍѤ¤¤ë¡£libc-5.4.6 °Ê¹ß¤Ç¤Ï¡¢¤³¤ì¤¬»È¤¨¤Ê¤«¤Ã¤¿¾ì¹ç¤Ë¤Ï /usr/share/zoneinfo ¤ò»È¤ª¤¦¤È¤¹¤ë¡£ glibc2 ¤Ç¤Ï´Ä¶­ÊÑ¿ô TZDIR ¤¬Â¸ºß¤¹¤ì¤Ð¤½¤ì¤òÍѤ¤¤ë¡£ ¤³¤Î¥Ç¥Õ¥©¥ë¥È¤Ï¤É¤Î¤è¤¦¤Ë¥¤¥ó¥¹¥È¡¼¥ë¤µ¤ì¤¿¤«¤Ë¤è¤ë¤¬¡¢ ÉáÄÌ¤Ï /usr/share/zoneinfo ¤Ç¤¢¤ë¡£

¤³¤Î¥¿¥¤¥à¥¾¡¼¥ó¥Ç¥£¥ì¥¯¥È¥ê¤Ë¤Ï°Ê²¼¤Î¥Õ¥¡¥¤¥ë¤¬´Þ¤Þ¤ì¤ë¡£

localtime      ¥í¡¼¥«¥ë¥¿¥¤¥à¥¾¡¼¥ó¤Î¥Õ¥¡¥¤¥ë

posixrules     POSIX ¼°¤Î TZ ½ñ¼°¥ë¡¼¥ë

/etc/localtime ¤Ï¡¢ 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¿¤¤¡£

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SVr4, POSIX.1-2001, 4.3BSD

Ãí°Õ

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 gettimeofday(2) ¤Î tz_dsttime ÊÑ¿ô¤ò¸«¤è)¡£ ¤³¤ì¤Ï¤â¤¦²¿Ç¯¤â»È¤ï¤ì¤Æ¤¤¤Ê¤¤¤¬¡¢SUSv2 ¤Ç¤ÏɬÍפȤµ¤ì¤Æ¤¤¤ë¡£

4.3BSD ¤Ë¤Ï char *timezone(zone, dst) ¤È¤¤¤¦¥ë¡¼¥Á¥ó¤¬¤¢¤ê¡¢¤³¤ì¤Ï ºÇ½é¤Î°ú¿ô (GMT ¤«¤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¡£

´ØÏ¢¹àÌÜ

date(1), gettimeofday(2), time(2), ctime(3), getenv(3), tzfile(5)