Does a DLL stay loaded during execution?

[David@Work]

Can anyone tell me if a DLL called from a Call Library Function Node stays loaded in memory until the LV code execution completes?

Thanks in advance,

David Dupont

[JonathanN]

Hi David,

The DLL will be un-loaded from memory when the VI that contains that Call Library Function Node is un-loaded from memory. Check out the When Does the DLL Specified By a Call Library Function Node Get Loaded Into Memory? and When Does LabVIEW Load a DLL Called from a Call Library Function? KnowledgeBases.

Best Regards,

[David@Work]

Jonathan,

Thanks.  That's what I was hoping would be the answer.  On the down side, that means I have to find the real reason for the unusual operation 😞

David

[chrisger]

hi there

well, what IS the unusual operation?

[David@Work]

I've re-created the calls to an existing DLL from a test stand sequence file that control an RF switch matrix.  In the original test stand code, I can move the switches all day without any problems.  In the re-created LV code, after the first two moves, the switch matrix stops responding, until I re-initialize the whole thing.  Additionally it appears that the moves in the LV code aren't really the same, as I cannot measure RF power from my sources in the expected places.

My origiinal thought was that if LV didn't keep the DLL loaded, then some global variables that are used in the DLL would be lost between calls, and that might have been the cause of the problem.  Since that's not the case, I'm now back to square one.

I appreciate your interest, and welcome any suggestions, but without providing more information than would be practical about our setup, I don't expect any suggestions will be greatly helpful.

Thanks anyhow,

David