#include <stdio.h>
#include <time.h>

main()
{
	time_t *timer, hardware_timer = 1000000; 
	timer = &hardware_timer;
	printf("%s", asctime(localtime(timer)));

	time(timer);
	printf("%s", asctime(localtime(timer)));
}

/*
 *      ISO C99 Standard: 7.23 Date and time    <time.h>
 *

type
	size_t		clock_t		time_t
	struct tm
	{
	  int tm_sec;                   * Seconds.     [0-60] (1 leap second) *
	  int tm_min;                   * Minutes.     [0-59] *
	  int tm_hour;                  * Hours.       [0-23] *
	  int tm_mday;                  * Day.         [1-31] *
	  int tm_mon;                   * Month.       [0-11] *
	  int tm_year;                  * Year - 1900.  *
	  int tm_wday;                  * Day of week. [0-6] *
	  int tm_yday;                  * Days in year.[0-365] *
	  int tm_isdst;                 * DST.         [-101]*
	  long int __tm_gmtoff;         * Seconds east of UTC.  *
	  __const char *__tm_zone;      * Timezone abbreviation.  *
	};

macro
	CLOCKS_PER_SECOND

functions
	clock		clock_t clock(void)
	difftime	double difftime(time_t time1, time_t time0)
	mktime		time_t mktime(struct tm *timeptr)
	time		time_t time(time_t *timer)
	asctime		char *asctime(const struct tm *timeptr)
	ctime		char ctime(const time_t *timer)
	gmtime		struct tm *gmtime(const time_t *timer)
	localtime	struct tm *localtime(const time_t *timer)
	strftime	size_t strftime(char *s, size_t maxsize,
				 const char *format, const struct tm *timeptr)
*/