Converts the local time information into seconds since the epoch.
#include <time.h>
time_t mktime (
struct tm *localtime);
(IN) Points to the tm structure containing the local time information to convert.
If successful, returns the converted time. Otherwise, returns -1.
The mktime function converts the local time information in the structure pointed to by the localtime parameter into a calendar time with the same encoding used by the time function. Calendar time is expressed in seconds since the epoch began (January 1, 1970, 00:00:00).
The mktime function sets the local timezone information.