4.3BSD-UWisc/man/cat2/gettimeofday.2

GETTIMEOFDAY(2)     UNIX Programmer's Manual      GETTIMEOFDAY(2)



NAME
     gettimeofday, settimeofday - get/set date and time

SYNOPSIS
     #include <sys/time.h>

     gettimeofday(tp, tzp)
     struct timeval *tp;
     struct timezone *tzp;

     settimeofday(tp, tzp)
     struct timeval *tp;
     struct timezone *tzp;

DESCRIPTION
     The system's notion of the current Greenwich time and the
     current time zone is obtained with the _g_e_t_t_i_m_e_o_f_d_a_y call,
     and set with the _s_e_t_t_i_m_e_o_f_d_a_y call.  The time is expressed
     in seconds and microseconds since midnight (0 hour), January
     1, 1970.  The resolution of the system clock is hardware
     dependent, and the time may be updated continuously or in
     ``ticks.'' If _t_z_p is zero, the time zone information will
     not be returned or set.

     The structures pointed to by _t_p and _t_z_p are defined in
     <_s_y_s/_t_i_m_e._h> as:

          struct timeval {
               long tv_sec;        /* seconds since Jan. 1, 1970 */
               long tv_usec;       /* and microseconds */
          };

          struct timezone {
               int  tz_minuteswest;     /* of Greenwich */
               int  tz_dsttime;    /* type of dst correction to apply */
          };

     The _t_i_m_e_z_o_n_e structure indicates the local time zone (meas-
     ured in minutes of time westward from Greenwich), and a flag
     that, if nonzero, indicates that Daylight Saving time
     applies locally during the appropriate part of the year.

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

RETURN
     A 0 return value indicates that the call succeeded.  A -1
     return value indicates an error occurred, and in this case
     an error code is stored into the global variable _e_r_r_n_o.

ERRORS
     The following error codes may be set in _e_r_r_n_o:




Printed 12/27/86          May 14, 1986                          1






GETTIMEOFDAY(2)     UNIX Programmer's Manual      GETTIMEOFDAY(2)



     [EFAULT]       An argument address referenced invalid
                    memory.

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

SEE ALSO
     date(1), adjtime(2), ctime(3), timed(8)















































Printed 12/27/86          May 14, 1986                          2