關(guān)于夏令時(shí)取時(shí)間戳的問題。

flyfeel

根據(jù)用戶輸入需要對(duì)應(yīng)的日期轉(zhuǎn)成時(shí)間戳傳給程序，用的是struct tm賦值, mktime(&tm)轉(zhuǎn)時(shí)間戳。
問題是，當(dāng)系統(tǒng)的時(shí)區(qū)調(diào)到支持夏令時(shí)區(qū)時(shí)，（.e.g. GMT-5）則會(huì)在進(jìn)出夏令時(shí)有問題，


測試程序如下：

//GMT-5         struct tm tm1;         struct tm tm2;         time_t clock;         //3-8 00:00         memset(&tm1, 0, sizeof(tm1));         memset(&tm2, 0, sizeof(tm2));         tm1.tm_year = 109;         tm1.tm_mon = 2;         tm1.tm_mday = 8;         tm1.tm_hour = 0;         tm1.tm_min = 0;         tm1.tm_sec = 0;         tm1.tm_isdst = 0;         printf("before: %04d-%02d-%02d %02d:%02d:%02d\n", tm1.tm_year+1900,tm1.tm_mon+1,tm1.tm_mday,tm1.tm_hour,tm1.tm_min,tm1.tm_sec);         printf("before: tm_isdst = %d\n", tm1.tm_isdst);         clock = mktime(&tm1);         printf("%d\n", (int)clock);         localtime_r(&clock, &tm2);         printf("after: %04d-%02d-%02d %02d:%02d:%02d\n", tm2.tm_year+1900,tm2.tm_mon+1,tm2.tm_mday,tm2.tm_hour,tm2.tm_min,tm2.tm_sec);         //printf("%s\n", tm1.tm_zone);                  printf("------------------------------\n");                  //11-2 00:00         memset(&tm1, 0, sizeof(tm1));         memset(&tm2, 0, sizeof(tm2));         tm1.tm_year = 109;         tm1.tm_mon = 10;         tm1.tm_mday = 1;         tm1.tm_hour = 0;         tm1.tm_min = 0;         tm1.tm_sec = 0;         tm1.tm_isdst = 0;         printf("before: %04d-%02d-%02d %02d:%02d:%02d\n", tm1.tm_year+1900,tm1.tm_mon+1,tm1.tm_mday,tm1.tm_hour,tm1.tm_min,tm1.tm_sec);         printf("before: tm_isdst = %d\n", tm1.tm_isdst);         clock = mktime(&tm1);         printf("%d\n", (int)clock);         localtime_r(&clock, &tm2);         printf("after: %04d-%02d-%02d %02d:%02d:%02d\n", tm2.tm_year+1900,tm2.tm_mon+1,tm2.tm_mday,tm2.tm_hour,tm2.tm_min,tm2.tm_sec);

當(dāng)tm.tm_isdst = 0 (不啟用夏令時(shí))時(shí)，則進(jìn)入夏令時(shí)OK,出夏令時(shí)會(huì)多一個(gè)小時(shí)。
root@UTM25:/opt/CPSecure/webui/private# ./test
before: 2009-03-08 00:00:00
before: tm_isdst = 0
1236488400
after: 2009-03-08 00:00:00
------------------------------
before: 2009-11-01 00:00:00
before: tm_isdst = 0
1257051600
after: 2009-11-01 01:00:00

當(dāng)tm.tm_isdst = 1(啟用夏令時(shí)) 時(shí)，則進(jìn)入夏令時(shí)時(shí)間會(huì)提前一個(gè)小時(shí),出夏令時(shí)OK。
root@UTM25:/opt/CPSecure/webui/private# ./test
before: 2009-03-08 00:00:00
before: tm_isdst = 1
1236484800
after: 2009-03-07 23:00:00
------------------------------
before: 2009-11-01 00:00:00
before: tm_isdst = 1
1257048000
after: 2009-11-01 00:00:00

[ 本帖最后由 flyfeel 于 2009-6-15 10:57 編輯 ]