Passing Engine Handle to LabWindows CVI

[DaveC]

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

[RayFarmer]

Hi,

Do you actually set the parameter Engine to anything when you call your sequence.

In your DLL function call, just pass an obj handle "RunState.Engine".

Regards

Ray Farmer

[DaveC]

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.

[RayFarmer]

Hi DaveC,

I dont know why you are passing that struct, but all you need is a CAObjHandle and link either the SequenceContext or the RunState.Engine in the DLL Adapter specification.

Have a look at the Using LabWindows/CVI with TestStand manual 4-3,4,5,6&7 for calling code modules with Struct Parameters, if thats what you really need to pass.

Regards

Ray Farmer

[DaveC]

Ahh, I see more clearly now.  I was using the C/C++ DLL adaptor and passing a TSObject to my DLL when I should have been using a CVI Adaptor and passing a CVI ActiveX Automation Handle Object to my DLL.  This is where I was getting myself confused, but you have helped me see the light.  Thanks Ray!