1 #include "time_impl.h"
2 #include <errno.h>
3
mktime(struct tm * tm)4 time_t mktime(struct tm *tm)
5 {
6 struct tm new;
7 long opp;
8 long long t = __tm_to_secs(tm);
9
10 __secs_to_zone(t, 1, &new.tm_isdst, &new.__tm_gmtoff, &opp, &new.__tm_zone);
11
12 if (tm->tm_isdst>=0 && new.tm_isdst!=tm->tm_isdst)
13 t -= opp - new.__tm_gmtoff;
14
15 t -= new.__tm_gmtoff;
16 if ((time_t)t != t) goto error;
17
18 __secs_to_zone(t, 0, &new.tm_isdst, &new.__tm_gmtoff, &opp, &new.__tm_zone);
19
20 if (__secs_to_tm(t + new.__tm_gmtoff, &new) < 0) goto error;
21
22 *tm = new;
23 return t;
24
25 error:
26 errno = EOVERFLOW;
27 return -1;
28 }
29