2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1987, 1993
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32 #include <sys/cdefs.h>
33 __SCCSID("@(#)timezone.c 8.1 (Berkeley) 6/4/93");
34 __FBSDID("$FreeBSD$");
36 #include <sys/types.h>
41 #define TZ_MAX_CHARS 255
43 char *_tztab(int, int);
47 * The arguments are the number of minutes of time you are westward
48 * from Greenwich and whether DST is in effect. It returns a string
49 * giving the name of the local timezone. Should be replaced, in the
50 * application code, by a call to localtime.
53 static char czone[TZ_MAX_CHARS]; /* space for zone name */
56 timezone(int zone, int dst)
61 if ( (beg = getenv("TZNAME")) ) { /* set in environment */
62 if ((end = strchr(beg, ','))) { /* "PST,PDT" */
66 (void)strncpy(czone,beg,sizeof(czone) - 1);
67 czone[sizeof(czone) - 1] = '\0';
73 return(_tztab(zone,dst)); /* default: table or created zone */
81 {-1*60, "MET", "MET DST"}, /* Middle European */
82 {-2*60, "EET", "EET DST"}, /* Eastern European */
83 {4*60, "AST", "ADT"}, /* Atlantic */
84 {5*60, "EST", "EDT"}, /* Eastern */
85 {6*60, "CST", "CDT"}, /* Central */
86 {7*60, "MST", "MDT"}, /* Mountain */
87 {8*60, "PST", "PDT"}, /* Pacific */
89 /* there's no way to distinguish this from WET */
90 {0, "GMT", 0}, /* Greenwich */
92 {0*60, "WET", "WET DST"}, /* Western European */
93 {-10*60,"EST", "EST"}, /* Aust: Eastern */
94 {-10*60+30,"CST", "CST"}, /* Aust: Central */
95 {-8*60, "WST", 0}, /* Aust: Western */
101 * check static tables or create a new zone name; broken out so that
102 * we can make a guess as to what the zone is if the standard tables
103 * aren't in place in /etc. DO NOT USE THIS ROUTINE OUTSIDE OF THE
107 _tztab(int zone, int dst)
112 for (zp = zonetab; zp->offset != -1;++zp) /* static tables */
113 if (zp->offset == zone) {
114 if (dst && zp->dlzone)
116 if (!dst && zp->stdzone)
120 if (zone < 0) { /* create one */
126 (void)snprintf(czone, sizeof(czone),
127 "GMT%c%d:%02d",sign,zone / 60,zone % 60);