mktime转换

Question

我想计算GMT时间和当前时间的时间差。为此，我使用mktime将tm时间(以格林威治时间为单位)转换为time_t格式。和使用time() api的当前时间。

struct tm = x;  time_t t1, t2; 
time(&t1);
/* here x  will get in GMT format */
t2 = mktime(&x);
sec = difftime(t2 , t1);

在使用相同时区的情况下，mktime()会负责转换为本地时间吗？或者我应该显式地添加sec = difftime(t2 , gmtime(&t1);感谢

Answer 1

Yes mktime转换为本地时间，请阅读此文：

http://www.mkssoftware.com/docs/man3/mktime.3.asp

mktime() : convert local time to seconds since the Epoch

编辑：要计算两个日期之间的差异时间，可以使用以下命令

    time_t t1, t2;
    struct tm my_target_date;

    /* Construct your date */
    my_target_date.tm_sec = 0;
    my_target_date.tm_min = 0;
    my_target_date.tm_hour = 0;
    my_target_date.tm_mday = 20;
    my_target_date.tm_mon = 7;
    my_target_date.tm_year = 112; /* Date today */
    t1 = mktime (&my_target_date);
    t2 = time (NULL);
    printf ("Number of days since target date : %ld\n", (t2 - t1) / 86400); /* 1 day = 86400 sec, use 3600 if you want hours */