How can I calling LabView DLL within LabView and pass similar Data Types?

Question

I am trying to use an Instrument Driver, which is created in LabView6.1 as a DLL. At this point I have only LabView to test this DLL. I was wondering, is there easy way to find out what sort of Parameter or Data Type I should be using.
How can I pass the following data with in LabView:
LVRefnum as Type?
LVBoolean as Type?
TD1 (a structure) as Type?
It is funny to see that I am able to create a DLL in labview but having trouble calling it within LabView. I thought, it would be easier to test the DLL within the same environment.
Basically, I am more worried about the VISA calls that are used in the driver to communicate with instrument. Because, there is no link to �VISA32.dll� in
the header file, is that handled by the LV Run-time engine? I guess more details are needed on using the LabView DLL within LabView from National Instrument Technical Support.
Attachments:
RL5000.h ‏1 KB

Answer 1

A LVRefNum seems to be an unsigned long data type (32bit). You can cast it
in LV then use that as a parameter to call the DLL. (an Occurrence type
seems to be a Ulong32)
When you created the DLL what was the resulting type for the LVRefNum?
Happy Holidays
"Enrique" wrote in message
news:[email protected]..
> I see...
>
> After doing some research, it seems to me that there is no easy way to
> find out the type of data, other than looking at the header file and
> have documents like Using External Code in LabVIEW handy. The
> following information is from that document:
>
> LVBoolean is an 8-bit integer. 1 if TRUE, 0 if FALSE.
>
> LabVIEW specifies file refnums using t
he LVRefNum data type, the
> exact structure of which is private to the file manager. To pass
> references to open files into or out of a CIN, convert file refnums to
> file descriptors, and convert file descriptors to file refnums using
> the functions described in Chapter 6, Function Descriptions.
>
> I know you are creating a dll in LabVIEW, but I am pretty sure the
> information applies as well and is useful. For your dll this can be
> interpreted that, rather than passing a LVRefnum, try passing the file
> descriptor.
>
> From the header file, is can be deduced that TD1 is a cluster in
> LabVIEW.
>
> You are right in saying that "more details are needed on using the
> LabView DLL within LabView from National Instrument Technical
> Support.".
>
> Enrique