comp.lang.idl-pvwave archive: archive »

Home » Public Forums » archive » _extra keyword

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: _EXTRA KEYWORD [message #68624 is a reply to message #43326]

Wed, 11 November 2009 16:23

ben.bighair
Messages: 221
Registered: April 2007

Senior Member

On Nov 11, 5:47 pm, mankoff <mank...@gmail.com> wrote:
> On Nov 9, 1:09 am, Reimar Bauer <R.Ba...@fz-juelich.de> wrote:
>
>> dandan schrieb:
>
>>> Hi, everyone,
>>> Dose _EXTRA pass the keywords from the caller to called routine or the
>>> opposite?
>
>> You may be also interested into the _REF_EXTRA keyword.
>
>> The presence of a name in the _REF_EXTRA value indicates that a keyword
>> of that name was passed, and its value is available to be passed on in a
>> function or procedure call (using either _EXTRA or _STRICT_EXTRA).
>
>> cheers
>> Reimar
>
> I still have not entirely wrapped my head around _EXTRA, _REF_EXTRA,
> and _STRICT_EXTRA despite numerous readings of discussions on this
> group about these keywords.
>
> Does anyone have a graphical explanation of these? A flow-chart with
> arrows and diamonds and YES/NO keywords perhaps? I have a feeling that
> would get the concept across. If not, perhaps I'll take what I do
> understand of these keywords and try to create such a chart.
>
> -k.

Hi,

I am not sure if this analogy is correct, but it works for my limited
use. Assume that _EXTRA and _REF_EXTRA are fishing lines.

_REF_EXTRA has bait and a hook so you can pull things back. A
_REF_EXTRA is passed by reference - so you can send in a value but if
it is modified (like an output keyword) then the reference will
reflect that change. This is how you can land the trout, so to
speak.

On the other hand, _EXTRA has bait but no hook so you can send things
down in but not get them back. That is because _EXTRA is passed by
value - any modifications the trout makes under water are hidden from
you.

_STRICT_EXTRA is just like _EXTRA, but if you use the wrong kind of
bait the trout will complain (or issue an error and stop if they know
any IDL).

Even if my analogy is correct, it might be too simplistic to be
complete. Hope it helps.

Cheers,
Ben

Report message to a moderator

[Message index]

		_extra keyword By: antonioolita on Fri, 01 April 2005 02:12
		Re: _extra keyword By: David Fanning on Thu, 07 April 2005 12:58
		Re: _extra keyword By: Michael Wallace on Thu, 07 April 2005 12:52
		Re: _extra keyword By: David Fanning on Thu, 07 April 2005 05:33
		Re: _EXTRA KEYWORD By: dandan on Wed, 04 November 2009 23:37
		Re: _EXTRA KEYWORD By: David Fanning on Wed, 04 November 2009 15:22
		Re: _EXTRA KEYWORD By: David Fanning on Wed, 11 November 2009 19:01
		Re: _EXTRA KEYWORD By: Michael Galloy on Wed, 11 November 2009 18:54
		Re: _EXTRA KEYWORD By: David Fanning on Wed, 11 November 2009 17:36
		Re: _EXTRA KEYWORD By: ben.bighair on Wed, 11 November 2009 16:23
		Re: _EXTRA KEYWORD By: mankoff on Wed, 11 November 2009 14:47

Previous Topic:	Re: Tough System Variable Question for the IDL Gurus
Next Topic:	DICOM write: invalid character for this VR

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 19:20:42 PDT 2025

Total time taken to generate the page: 0.00443 seconds