topic Re: Calculate GMT in Operating System - OpenVMS

Calculate GMT

Peter Zeiszler — Fri, 21 Nov 2008 21:40:33 GMT

Hi,

Hoping someone has a quick fix/script for this. Trying to find a way to calculate the GMT value from the current systems' time and SYS$TIMEZONE_DIFFERENTIAL.

Anyone have a quick lexical that did this?

Re: Calculate GMT

Hoff — Sat, 22 Nov 2008 03:13:31 GMT

Assuming you're in an integer timezone (and not one of the zones with a fraction of an hour), try:

$ x=f$cvtim("+" + f$extract((f$integer(f$trnlnm("SYS$TIMEZONE_DAYLIGHT_SAVING"))*4+3),1,f$trnlnm("SYS$TIMEZONE_RULE")) +":","ABSOLUTE")

Re: Calculate GMT

Dennis Handly — Sat, 22 Nov 2008 21:53:49 GMT

>Hoff: not one of the zones with a fraction of an hour

Two of those would be India and Venezuela.

Re: Calculate GMT

Hoff — Sun, 23 Nov 2008 03:25:25 GMT

Yep, I'm aware of the fractional DSTs. And that the DCL code might not work so hot with a negative offset from GMT. Also of the rumor that the US might finally free itself of the DST idea, too.

Re: Calculate GMT

Wim Van den Wyngaert — Tue, 25 Nov 2008 15:09:58 GMT

Remark : "3" can also be more characters. The standard says 3 or more char (wrote that down many tears ago, source unknown).

Wim

Re: Calculate GMT

Jan van den Ende — Tue, 25 Nov 2008 15:29:11 GMT

Wim,

>>>
(wrote that down many tears ago
<<<

Litterally? Did you get hurt by it that much? :-)

Proost.

Have one on me.

jpe

Re: Calculate GMT

Joseph Huber_1 — Wed, 26 Nov 2008 08:48:18 GMT

Hoffs DCL code, generalized for all time-zones
(at least I think so :-)

$dt3=-
f$extract((f$integer(f$trnlnm("SYS$TIMEZONE_DAYLIGHT_SAVING"))*4+3),-
3,f$trnlnm("SYS$TIMEZONE_RULE"))
$ dt2=f$extract(0,2,dt3)
$ dt1=f$extract(0,1,dt3)
$ if f$extract(0,1,dt1).eqs."-").or.(f$extract(0,1,dt1).eqs."+")
$ then
$ dt = dt2
$ else
$ dt="+"+dt1
$ if (f$extract(1,1,dt3).ges."0").and.-
(f$extract(1,1,dt3).les."9") then dt="+"+dt2
$ endif
$ if (f$extract(2,1,dt3).ges."0").and.(f$extract(2,1,dt3).les."9")
$ then
$ dt=dt3
$ endif
$ dt = dt+":"
$! show symbol dt
$ write sys$output f$cvtim(dt,"ABSOLUTE")

Re: Calculate GMT

Joseph Huber_1 — Wed, 26 Nov 2008 12:42:36 GMT

Ah stupid cut'n'paste interface -
in the above proc., the line
$if f$extract(0,1,dt1).eqs."-").or.(f$extract(0,1,dt1).eqs."+")

has to be
$if (f$extract ...

Re: Calculate GMT

Peter Zeiszler — Mon, 01 Dec 2008 16:30:09 GMT

Our support is moving to India now but the systems in question aren't located there.
I will play with the command files. Thanks.

Re: Calculate GMT

Peter Zeiszler — Tue, 02 Dec 2008 17:42:54 GMT

The command file worked great - even for the systems overseas.