time() is used to get the current calendar timing and date of the system. If the system time is not available "-1" is returned. This function can be called with a "NULL" pointer or with a pointer to a "time_t" variable.

    time_t time( time_t *time);

   #include <stdio.h>
   #include <time.h>
   int main ()
     {
        time_t  ptr;
        time ( &ptr );
        printf ( "Current local time is:: 
                 ctime is: %s", ctime (&ptr) );
        return 0;
     }

   Current local time is:: Mon Mar 09 13:05:10 2010

In the above example "time()" uses a "time_t" pointer, so that it is used with the "ctime()" to get the current local timing and date.