gettimeofday(3-BSD)MISC. REFERENCE MANUAL PAGES
gettimeofday(3-BSD)



NAME
     gettimeofday, settimeofday - get or set the date and time

SYNOPSIS
     cc [ flag... ] file ... -lucb
     #include <sys/time.h>
     int gettimeofday(tp, tzp)
     struct timeval *tp;
     struct timezone *tzp;      /* obsolete */
     int settimeofday(tp, tzp)
     struct timeval *tp;
     struct timezone *tzp;      /* obsolete */

DESCRIPTION
     The  system's  notion  of  the  current  Greenwich  time  is
     obtained  with  the gettimeofday call, and set with the set-
     timeofday call.  The current time is  expressed  in  elapsed
     seconds  and  microseconds  since 00:00 GMT, January 1, 1970
     (zero hour).  The resolution of the system clock is hardware
     dependent;  the  time  may  be  updated  continuously, or in
     ``ticks.''  tp points to a timeval structure, which includes
     the following members:
          long tvsec;  /* seconds since Jan. 1, 1970 */
          long tvusec; /* and microseconds */
     If tp is a NULL pointer, the current time information is not
     returned  or  set.  tzp is an obsolete pointer formerly used
     to get and set timezone information.  tzp  is  now  ignored.
     Timezone information is now handled using the TZ environment
     variable; see timezone(4).  Only the privileged user may set
     the time of day.

RETURN VALUE
     A -1 return value indicates an error occurred; in this  case
     an error code is stored in the global variable errno.

ERRORS
     The following error codes may be set in errno:

     EINVAL         tp specifies an invalid time.

     EPERM          A  user  other  than  the   privileged   user
                    attempted to set the time.

SEE ALSO
     date(1) in the User's Reference Manual.
     adjtime(2), ctime(3C), gettimeofday(3C), timezone(4) in  the
     Programmer's Reference Manual.

NOTES
     Time is never correct  enough  to  believe  the  microsecond
     values.  tzp is ignored.




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