HPUX gettimeofda[2]

 gettimeofday(2)                                             gettimeofday(2)





 NAME
      gettimeofday, settimeofday - get/set date and time

 SYNOPSIS
      #include <time.h>

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

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

 DESCRIPTION
      gettimeofday() returns and settimeofday() sets the system's notion of
      the current Coordinated Universal Time (UTC) and the system's notion
      of the current time zone.  Time is expressed in seconds and
      microseconds since midnight January 1, 1970.

      The structures pointed to by tp and tzp are defined in <time.h> as:

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

           struct timezone {
              int     tz_minuteswest;    /* of UTC */
              int     tz_dsttime;        /* type of DST correction to apply */
           };

      The timezone structure indicates the local time zone (measured in
      minutes of time westward from UTC), and a flag that, if nonzero,
      indicates that Daylight Savings Time applies locally during the
      appropriate part of the year.  Programs should use this timezone
      information only in the absence of the TZ environment variable.

      Only users with appropriate privileges can set the time of day.

 EXAMPLES
      The following example calls gettimeofday() twice.  It then computes
      the lapsed time between the calls in seconds and microseconds and
      stores the result in a timeval structure:

           struct timeval        first,
                                 second,
                                 lapsed;
           struct timezone tzp;



 Hewlett-Packard Company            - 1 -     HP-UX Release 9.0: August 1992






 gettimeofday(2)                                             gettimeofday(2)





              gettimeofday (&first, &tzp);

           /* lapsed time */

              gettimeofday (&second, &tzp);

           if (first.tv_usec > second.tv_usec) {

              second.tv_usec += 1000000;
              second.tv_sec--;

           }
           lapsed.tv_usec = second.tv_usec - first.tv_usec;
           lapsed.tv_sec = second.tv_sec - first.tv_sec;

 RETURN VALUE
      gettimeofday() and settimeofday() return 0 on success; otherwise, if
      an error occurs, they return -1 and set errno to indicate the error.

 ERRORS
      gettimeofday() and settimeofday() fail if any of the following
      conditions are encountered:

           [EFAULT]       An argument address referenced invalid memory.
                          The reliable detection of this error will be
                          implementation dependent.

           [EPERM]        A user lacking appropriate privileges attempted to
                          set the time.

 WARNINGS
      The microsecond value usually has a granularity much greater than one
      due to the resolution of the system clock.  Relying on any granularity
      (particularly of one) will render code non-portable.

 DEPENDENCIES
    Series 300/400
      gettimeofday() has a granularity of 4 microseconds.

    Clustered Systems
      In an HP Clustered Environment, setting the time of day sets the date
      and timezone on all systems in the cluster.

 AUTHOR
      gettimeofday() was developed by the University of California,
      Berkeley.

 SEE ALSO
      date(1), stime(2), time(2), ctime(3C), privilege(5).





 Hewlett-Packard Company            - 2 -     HP-UX Release 9.0: August 1992