[Info-vax] %DCL-W-IVDTIME and the DCL WAIT command:SUMMARY

[George Cornelius]

In article <00ABBF0B.F0E4845C at SendSpamHere.ORG>,   VAXman-  @SendSpamHere.ORG writes:
> You can WAIT with absolute time.  In this case, use:
> 
> $ WAIT 'F$cvtime("+1-12::","ABSOLUTE")

To resurrect a rather old practice, I'll summarize the results of this
discussion:

  I. WAIT has an unusual time syntax.  It accepts only a
     subset of delta time, and does not accept the leading
     plus sign that might be expected for a delta time.  It
     also ignores blanks within all numeric fields.

 II. Online VMS resources - the message database, and the
     online help - on the surface seem to imply that full
     delta-time syntax is accepted, and one message goes so
     far as to give the full DDDD-HH:MM:SS.SS syntax as
     being what is needed.  Only if you drill down one level
     deeper, to $ HELP WAIT PARAMETER , do you find that it
     does not accept the DDDD or the dash.  The DCL Dictionary
     is unambiguous, however, and correct.

III. Brian has pointed out an undocumented syntax.  You
     can use 'F$CVTIME("+1-12:00","ABSOLUTE") to get the
     equivalent of an acceptance of the full delta time syntax,
     and that means you can actually specify a target date
     and time on the command line.

 IV. Solution to first puzzle:

      $ WAIT 2 0:0:)

     waits 20 hours.  The others two items are unanswered
     but we can make some educated guesses.

  V. Solution to second puzzle, i.e., concerning Brian's syntax:

         $ WAIT 25-JAN-2012 16:39

     does not wait until 16:36:00 .  Instead, it supplies
     current value for the missing SS.SS field, making it
     a mix between absolute and delta time.  Since the
     start time in the example was 16:38:15, the wait
     in fact terminated at

         25-JAN-2012 16:39:15

     The .SS portion would have been identical as well if
     the $ SHOW TIME command could have displayed it.

George