time(2)

NAME
     time, stime - get/set date and time

SYNOPSIS
     #include <sys/types.h>
     #include <time.h>

     time_t time(time_t *tp)
     int stime(time_t *tp)

DESCRIPTION
     The system's notion of the current Greenwich time is  obtained  with  the
     time call, and set with the stime call.  The time is expressed in seconds
     since midnight (0 hour), January 1, 1970.  The time is both  returned  by
     time  and  stored  in the variable pointed to by tp unless tp is the null
     pointer.

     Stime obtains the time to set from the variable pointed to by tp.

     Only the super-user may set the time of day.

RETURN
     A 0 return value from stime indicates  that  the  call  succeeded.   Time
     returns  the  current  time  on  success.  A -1 return value indicates an
     error occurred, and in this case an error code is stored into the  global
     variable errno.

ERRORS
     The following error codes may be set in errno:

     [EFAULT]       The tp address referenced invalid memory.

     [EPERM]        A user other than the  super-user  attempted  to  set  the
                    time.

SEE ALSO
     date(1), ctime(3).