How do I obtain a vi reference in a dll

[Steve_Block]

I want the DLL to run a main loop and allow the calling program to call vis to control it. I'm having trouble loading the vi server reference once compiled.

[Steve_Block]

The Open Vi Reference does not work when compiled.

[Steve_Block]

Looks like I got it to work.

[User002]

Steve,

others might find it helpful if you shared the solution you found here.

Kind regards

[Steve_Block]

I had to use a text string instead of file path. The problem I have now is that the DLL is only running single thread and the GUI is not accepting user input. Is there a way to enable this?

[nathand]

Please provide more information. What language is the calling program written in? Is it the LabVIEW GUI that isn't accepting input? What do you mean by "not accepting input" - the GUI appears, but you can't click anything in it? Or something else? Have you tried enabling remote debugging, then connecting to the running VI from the development environment? I'm pretty sure this works for VIs inside DLLs, although I haven't tested it.

[Steve_Block]

The dll is a labview compiled dll. Once I exit the launching call, the GUI appears but does not accept mouse clicks on any of the buttons.

[nathand]

Is there any continuously-running loop in your DLL so that the UI can respond to user interaction? If not, then of course it won't respond. In order to have a loop in the DLL run in parallel with your other code, the calling code needs to spawn a separate thread, then launch the DLL loop in it.

[Steve_Block]

It is a standard event based queue driven state machine. I opened it this way but opted not to wait for the vi to complete and did not close the reference.

https://decibel.ni.com/content/docs/DOC-3413

It turns out that the GUI will lock up independently of whether it is compiled into a DLL so I don't know what else could be the cause.

[nathand]

If I understand correctly, you're calling a DLL built in LabVIEW, from LabVIEW? Why? If you do the same thing but without building the called VI into a DLL, it still "locks up" the same way? Can you create a simplified example the demonstrates the same problematic behavior?