NAME    [Toc]    [Back]

     gettimeofday, settimeofday - get/set date and time

SYNOPSIS    [Toc]    [Back]

     #include <sys/time.h>

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

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

DESCRIPTION    [Toc]    [Back]

     Note:  timezone  is no longer used; this information is kept
outside the
     kernel.

     The system's notion of the current Greenwich  time  and  the
current time
     zone  is obtained with the gettimeofday() call, and set with
the
     settimeofday() 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 tp or tzp is NULL, the associated time information will
     not be returned or set.

     The structures pointed to by  tp  and  tzp  are  defined  in
<sys/time.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  timezone  structure indicates the local time zone (measured 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 superuser may set the time of day or time zone.  If
the system
     securelevel  is  greater  than 1 (see init(8)), the time may
only be advanced.
  This limitation is imposed to prevent  a  malicious
superuser from
     setting arbitrary time stamps on files.  The system time can
still be adjusted
 backwards using the adjtime(2) system call even  when
the system is
     secure.

RETURN VALUES    [Toc]    [Back]

     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 errno.

ERRORS    [Toc]    [Back]

     The following error codes may be set in errno:

     [EFAULT]  An argument address referenced invalid memory.

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

SEE ALSO    [Toc]    [Back]

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

HISTORY    [Toc]    [Back]

     The gettimeofday() function call appeared in 4.2BSD.

OpenBSD      3.6                           May      26,      1995