localtime

localtime, localtime_s

Defined in header <time.h>
struct tm *localtime( const time_t *time );
(1)
struct tm *localtime_s(const time_t *restrict time, struct tm *restrict result);
(2) (since C11)
1) Converts given time since epoch (a time_t value pointed to by time) into calendar time, expressed in local time, in the struct tm format. The result is stored in static storage and a pointer to that static storage