RE: 'Occurrence' OpenGOOP Object

[Rolf K. <rol...@ci...>]

Jean-Pierre,

You are right, but use "LabVIEW" instead. "LabVIEW.exe" will only work =
on
Windows as LabVIEW will just do a LoadLibrary on that name and it does =
not
have an exe extension on all platforms. But the "LabVIEW" keyword is
apparently trapped in the CLN function and directly redirected to its =
own
export function table without using the platform specifc LoadLibrary =
call.

You can see that when using "LabVIEW" you don't get any functions listed
in the Function name drop box as LabVIEW does aparently not support
enumerating directly the export table but you can get all the names if
you enter exactly the path the to LabVIEW.exe file, as LabVIEW then just
enumerates the export section of the executable image, which is exactly
the same for Win32 DLLs as it is for Win32 EXEs.

So you first enter the full path to LabVIEW.exe, then select the =
appropriate
function and then change the path to "LabVIEW". Now you just need to =
know
the exact prototypes ;-)

/* This is the same as the NotARefnum constant in LabVIEW */
#define kNonOccurrence  0

/* Basically the same as a LVRefNum, an opaque pointer to a LabVIEW =
private
data structure, which you should never try to assume anything about as =
it
may completely change between versions. I think current LabVIEW actually
uses here a so called cookie which is a 32 bit number only meaningful to
the instance who created it. */
Private(Occurrence);

Occurrence  AllocOccur(void);
MgErr Occur(Occurrence occ);
MgErr DeallocOccur(Occurrence o);

Rolf Kalbermatter

> -----Original Message-----
> From: Jean-Pierre Drolet [mailto:jea...@tr...]
> Sent: Wed, December 17, 2003 2:21 PM
> To: ope...@li...
> Subject: Re: 'Occurrence' OpenGOOP Object
>=20
>=20
> Jim,
>=20
> I think that by using CLNs within labview.exe to functions=20
> like AllocOccur and DeallocOccur you can create (new at each call) and
> destroy occurences. However, I don't know how platform=20
> (in)dependant it is. I'm sure Rolf has more to say about this...
>=20
> Jean-Pierre
>=20
>=20
> ----- Message d'origine -----=20
> De : "Jim Kring" <ji...@ji...>
> =C0 : "'OpenGToolkit-Developers'"=20
> <ope...@li...>
> Envoy=E9 : 16 d=E9cembre, 2003 23:06
> Objet : 'Occurrence' OpenGOOP Object
>=20
>=20
> Hello All,
>=20
> One thing that I have found bothersome about occurrences is that the
> 'Generate Occurrence' function is more of an Occurrence=20
> "constant" than a
> "generator".  Each call to an instance of 'Generate=20
> Occurrence' will return
> the same occurrence.  So, I wrapped the occurrence primitives=20
> in a stripped
> down OpenGOOP Class.  The data store contains only an=20
> occurrence, and there
> is one unique occurrence per object instance (since the data core is a
> reentrant LV2 global, called by reference).  Another added=20
> benefit of having
> OpenGOOP wrapper VIs around the occurrence primitives is that=20
> they have
> error IO, which makes data flow sequencing possible without=20
> the classic
> one-frame sequence structure.
>=20
> So, I have a few questions:
>=20
> Does it make sense to augment the default behavior of=20
> occurrences?  If so,
> what features and behaviors should be implemented?  Is this=20
> tool useful?
>=20
> Regards,
>=20
> -Jim
>=20
>=20
>=20
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>=20
>=20