RE: 'Occurrence' OpenGOOP Object

[Jim K. <ji...@ji...>]

Rolf,

I was able to get AllocOccur, Occur, and DeallocOccur.  They seem to =
work
great.  I also noticed the following functions exported by LabVIEW.exe
(LV70), which look interesting.

AllocOccurHdlr
OccurAtTime
OnOccurrence
OnOccurrenceWithTimeout
InterruptSafeOccur

I would presume that 'OnOccurrenceWithTimeout' is analagous to the 'Wait =
on
Occurrence' primitive... is this right?

-Jim


> -----Original Message-----
> From: ope...@li...=20
> [mailto:ope...@li...]=20
> On Behalf Of Rolf Kalbermatter
> Sent: Thursday, December 18, 2003 12:21 AM
> To: ope...@li...
> Subject: RE: 'Occurrence' OpenGOOP Object
>=20
>=20
> Jean-Pierre,
>=20
> You are right, but use "LabVIEW" instead. "LabVIEW.exe" will=20
> only work on Windows as LabVIEW will just do a LoadLibrary on=20
> that name and it does not have an exe extension on all=20
> platforms. But the "LabVIEW" keyword is apparently trapped in=20
> the CLN function and directly redirected to its own export=20
> function table without using the platform specifc LoadLibrary call.
>=20
> You can see that when using "LabVIEW" you don't get any=20
> functions listed in the Function name drop box as LabVIEW=20
> does aparently not support enumerating directly the export=20
> table but you can get all the names if you enter exactly the=20
> path the to LabVIEW.exe file, as LabVIEW then just enumerates=20
> the export section of the executable image, which is exactly=20
> the same for Win32 DLLs as it is for Win32 EXEs.
>=20
> So you first enter the full path to LabVIEW.exe, then select=20
> the appropriate function and then change the path to=20
> "LabVIEW". Now you just need to know the exact prototypes ;-)
>=20
> /* This is the same as the NotARefnum constant in LabVIEW */=20
> #define kNonOccurrence  0
>=20
> /* Basically the same as a LVRefNum, an opaque pointer to a=20
> LabVIEW private data structure, which you should never try to=20
> assume anything about as it may completely change between=20
> versions. I think current LabVIEW actually uses here a so=20
> called cookie which is a 32 bit number only meaningful to the=20
> instance who created it. */ Private(Occurrence);
>=20
> Occurrence  AllocOccur(void);
> MgErr Occur(Occurrence occ);
> MgErr DeallocOccur(Occurrence o);
>=20
> Rolf Kalbermatter
>=20
> > -----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
> > like AllocOccur and DeallocOccur you can create (new at=20
> 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 -----
> > 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=20
> that the=20
> > 'Generate Occurrence' function is more of an Occurrence "constant"=20
> > than a "generator".  Each call to an instance of 'Generate
> > 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=20
> 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
> > 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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