Passing Engine Handle to LabWindows CVI

Question

Hi All,
I have run into a situation in test stand where I want to use it in conjunction with a DLL that I have developed in CVI.  In order have them interact properly, I wanted to pass the current TestStand Engine handle into my CVI DLL.  Afterwards, the plan is to use that engine handle along with the tsapicvi activeX control to do what I need to do.
However, I cannot seem to get this working correctly, as I keep getting an invalid handle error from my CVI activeX controls with the handle I have passed into it from teststand.  Here is what I have so far.
In TestStand Sequence A calls the CVI DLL:
Sequence A has a single parameter called Engine.
Parameter Engine has the teststand Category TSObject with type TS::IEngine passed By Value.
The value passed into the parameter Engine is RunState.Engine
The CVI DLL has a single function GetHandle
GetHandle has a single parameter which is TSObj_Engine *ts_engine.
This function calls TS_EngineGetLicenseDescription (*ts_engine, NULL, 0, &desc); (just a random function that I use to test it).
Any suggestions on where I might have gone wrong with this?
CVI 7.0
TestStand 3.1

Answer 1

Hi Ray,
Thanks for the quick response! 
To answer your question, yes, I do set the Engine parameter in TestStand to RunState.Engine.
 However, all I know about the TS:IEngine containter is that it has one (or more) data fields that get passed to my DLL.  I don't know what those fields are, so on the DLL end I am not sure what I should be getting.  i.e. the function prototype in my DLL should probably contain some struct, but I don't know what the struct is.  The only guess I can make is that teststand is passing me a TS_IID_Engine type struct (defined in tsapicvi.h).  However there are 4 data fields in this struct convienently labeled Data1 - Data4, all of which i tried using as a handle, and none of which worked.