Should a dot net Invoke node fill the error cluster?

Question

Situation, a dll called by LabVIEW attempts to communicate with an instrument and can not because the instrument is not present.  The DLL returns a standard LabVIEW error cluster with no error.
Person A says this is wrong : it must return an error.  Further modules in the chain can not succeed with no communication. And that it is possible to return an error by throwing an exception.
Person B says : The program ran and did not die.  This is our module not a LabView function.  The error cluster should return no error.  And that it can not return an error either,
The questions are Who is right A or B? And , since is has already gotten to a ‘is to, is not’ kind of disagreement, Where is any supporting documentation to reference that will authoritatively resolve the issue?
Solved!
Go to Solution.

Answer 1

In order for the dll to produce an error in LabVIEW, it must be programmed to throw an exception if no instrument is available.  LabVIEW will then convert this exception into a generic error with code 1172 (see attached article.)  LabVIEW can be programmed to give a custom error message using the attached example.  In this case, it should be possible to have the .NET dll throw an exception, and then have LabVIEW generate a custom error message to display to the user.  In this instance, it appears that Person A is correct.  Hope this helps resolve the issue.  
LabVIEW and .NET Exceptions
http://digital.ni.com/public.nsf/allkb/B15CE9F2715434C386256D3500601878
Programmatically Generate Custom Error Codes/Messages
https://decibel.ni.com/content/docs/DOC-9557
Regards,
Chris L
Applications Engineer
National Instruments
Certified LabVIEW Associate Developer