? F$DELTA_TIME returns a non-standard delta time format

[Robert_Boyd]

Does anybody know WHY F$DELTA_TIME returns a string which is not a valid OpenVMS delta time value? This means that if someone wants to use the return value for anything they have to massage it to get the "-" between the day and time portions of the value. It would be much simpler to have the lexical stuff the connector in to begin with.

In general -- I would like to think that system routines that operate on time values will always return a valid time construct whether absolute or delta.

Robert

[Robert_Boyd]

And ... another thing ... why is it that on V8.2 the HELP for the DCL WAIT command still doesn't mention that

$ WAIT

is also a valid command? It has worked as far back as I can remember ... and still works.

Is this an oversight? or a deliberate act of avoidance?

Robert

[Dale A. Marcy]

It will work if you enclose it in quotes with a + i.e.,

$ submit/after="+''f$delta_time(start,end)'" ...

start and end would be symbols containing the appropriate start and end times. I know the quotes are hard to distinguish sometimes in this forum, so I will repeat the above line below adding spaces between each type of quote above:

$ submit/after= " + ' ' f$delta_time(start,end) ' " ...

[Robert_Boyd]

Hmmmm ... that's an interesting proposition but I beg to differ ... for example:


$ say = "write sys$output"
$ say -
f$cvtime("+"+f$delta_time(f$cvtime("YESTERDAY","ABSOLUTE"),f$cvtime("TODAY","ABSOLUTE")))
%DCL-W-IVATIME, invalid absolute time - use DD-MMM-YYYY:HH:MM:SS.CC format
\+ 1 00:00:00.00\

[Robert_Boyd]

I can't get the submit example to work either:

$ xa = f$cvtime("YESTERDAY","ABSOLUTE")
$ xb = f$cvtime("TODAY","ABSOLUTE")
$ submit/after="+''f$delta_time(xa,xb)'" login.com
%DCL-W-IVATIME, invalid absolute time - use DD-MMM-YYYY:HH:MM:SS.CC format
\+ 1 00:00:00.00\

[Dale A. Marcy]

Sorry, you are correct. In my testing, I did not make my delta time larger than a day and it worked fine in that case. Which is interesting, because I would have thought the 0 in the day position would have caused the same error.

[John Gillings · Accepted solution]

Robert,

Excellent point. F$DELTA_TIME is returning a "standard" delta time as returned by SYS$ASCTIM. It's implemented as

$BINTIM P1 => Time1
$BINTIM P2 => Time2
LIB$SUB_TIMES Delta,Time1,Time2
$ASCTIM Delta => Output String

The trouble here is that DCL has extended the standard time string formats, and requires delta times to have a hyphen between the days and time fields.

It seems reasonable that it should return a delta time in DCL delta time format, rather than $ASCTIM format, and maybe trim off any leading white space at the same time. I'll send a suggestion to the engineer responsible.

(since F$DELTA time is new, hopefully not too many people have written code dependent on the output format, otherwise we might need to add a flag "DCL" to request a DCL format string)

[Guy Peleg]

Hi Robert,

Thank you for bringing this to our attention.

I have exchanged mail with John Gillings
based on his feedback I'll modify F$DELTA_TIME
to accept an optinal format argument

F$DELTA_TIME(start-time,end-time [,format])

format = "DCL" or "ASCTIM" (default)

This will show up in a future DCL kit for
V8.2 and V7.3-2 and will be incorporated
into the next VMS version.

Regards,

Guy Peleg
OpenVMS Engineering

[Jan van den Ende]

Robert,

Grab your chance!!

Give Guy (at least) 4 points, and see hime get his (WELL deserved) hat!

Proost.

Have one on me.

jpe

[Jan van den Ende]

Guy,

this thread set me thinking.

At this moment, F$DELTA is returning a time syntax, and you just promised to add a format specifier for ASCTIM or DCL format.

Would it be asking very much extra to add (more or less like F$CVTIM) the format specifiers SECONDS, MINUTES, HOURS, DAYS (WEEKS?, MONTHS?, YEARS?) as rounded-down integer values? I know for sure that at least _WE_ have regular use for them!
I know that this would be fairly easy to do in DCL, but it DOES require a number of string manipulations and arithmatic, and I have for a long time already been pleased with those formats from f$cvtime.

TIA

Proost.

Have one on me.

jpe