mktime转换

Question

我想计算GMT时间和当前时间的时差。为此我使用mktime将tm时间（格林威治标准时间）转换为time_t格式。和当前时间使用time（）api。

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

在这个用于制作相同时区的地方，mktime（）会照顾转换到当地时间吗？或者我是否需要明确添加sec = difftime(t2 , gmtime(&t1); 感谢

Answer 1

是mktime转换为当地时间，请阅读该人：

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，您可以使用此

    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 */