Gets the current value of the systemwide clock.

    Format

      #include  <timers.h>

      int getclock  (int clktyp, struct timespec *tp);

1  –  Arguments

 clktyp

    The type of systemwide clock.

 tp

    Pointer to a timespec structure space where the current value of
    the systemwide clock is stored.

2  –  Description

    The getclock function sets the current value of the clock
    specified by clktyp into the location pointed to by tp.

    The clktyp argument is given as a symbolic constant name,
    as defined in the <timers.h> header file. Only the TIMEOFDAY
    symbolic constant, which specifies the normal time-of-day clock
    to access for systemwide time, is supported.

    For the clock specified by TIMEOFDAY, the value returned by
    this function is the elapsed time since the Epoch. The Epoch
    is referenced to 00:00:00 UTC (Coordinated Universal Time) 1 Jan
    1970.

    The getclock function returns a timespec structure, which is
    defined in the <timers.h> header file as follows:

     struct  timespec {

      unsigned long  tv_sec   /* Elapsed time in seconds since the Epoch*/
      long           tv_nsec  /* Elapsed time as a fraction of a second */
                              /* since the Epoch (in nanoseconds)       */

     };

3  –  Return Values

    0                  Indicates success.
    -1                 Indicates an error; errno is set to one of the
                       following values:

                       o  EINVAL - The clktyp argument does not
                          specify a known systemwide clock.

                          Or, the value of SYS$TIMEZONE_DIFFERENTIAL
                          logical is wrong.

                       o  EIO - An error occurred when the systemwide
                          clock specified by the clktyp argument was
                          accessed.