You're right, maybe it won't work with an array of BSTR.
In this case I think we have to options since in LabWindows/CVI we have the possibility to store an array of BSTR as a pointer using the function CA_VariantSetBSTRPtr () but we can also store it as an array using the function CA_VariantSet1DArray ().
You can know which of them was used to create your variant by using the function CA_VariantHasPtr () that returns TRUE only if the variant was created using CA_VariantSetBSTRPtr () and you can use CA_VariantHasArray () that returns TRUE if the variant was created using the CA_VariantSet1DArray ().
Once you know how your variant was created you can convert it to the array of BSTR using the function CA_VariantGetBSTRPtr() or CA_VariantGet1DArray().
I created a little project and tested this functions.
As you can see, the code creates an array of BSTR strings and store them in two different variants using both the ways I explained and then convert the variant back to two array of strings (they are pointers actually) and take the first string of both pointer that can be seen into the watch-expression window.
Here you have the code:
size_t numberOfElements;
BSTR *myNEWBSTRArray;
BSTR *myNEWBSTRPointer;
HRESULT variantHasPointer;
HRESULT variantHasArray;
unsigned int variantTypeBSTRPointer;
unsigned int variantTypeBSTRArray;
BSTR myBSTR[3];
VARIANT myVariantBSTRPointer;
VARIANT myVariantBSTRArray;
char *ptrString;
char *arrayString;
BSTR firstOfPtr, firstOfArray ;
//Allocate Variants
myVariantBSTRPointer = CA_VariantEmpty ();
myVariantBSTRArray = CA_VariantEmpty ();
//Create the array of BSTR strings
myBSTR[0] = SysAllocString(L"I am a happy BSTR");
myBSTR[1] = SysAllocString(L"I am another happy BSTR");
myBSTR[2] = SysAllocString(L"I am one more happy BSTR");
//FIRST WAY: Convert the BSTR array to a BSTR pointer variant
CA_VariantSetBSTRPtr (&myVariantBSTRPointer, myBSTR);
//Get the variant type
variantTypeBSTRPointer = CA_VariantGetType (&myVariantBSTRPointer);
//this is true since the variant was created as BSTRPtr
variantHasPointer = CA_VariantHasPtr (&myVariantBSTRPointer);
// Retrieve the BSTR array as a new BSTR pointer
CA_VariantGetBSTRPtr (&myVariantBSTRPointer, &myNEWBSTRPointer);
//Take the first BSTR string stored in this array
firstOfPtr = myNEWBSTRPointer[0];
//SECOND WAY: Convert the BSTR array to a 1D array of BSTR variant
CA_VariantSet1DArray (&myVariantBSTRArray, CAVT_BSTR, 3, myBSTR);
//Get the variant type
variantTypeBSTRArray = CA_VariantGetType (&myVariantBSTRArray);
//this is true because this second variant was created as 1DArray
variantHasArray = CA_VariantHasArray (&myVariantBSTRArray);
//Retrieve the BSTR array as 1DArray.
//NOTE: myNEWBSTRArray is a BSTR* just like myNEWBSTRPointer variable was.
CA_VariantGet1DArray (&myVariantBSTRArray, CAVT_BSTR, &myNEWBSTRArray, &numberOfElements);
//Take the first BSTR string stored in this array
firstOfArray = myNEWBSTRArray[0];
//Convert the two BSTR strings to C-Strings that can be seen into the watch-expression
CA_BSTRGetCString (firstOfArray, &arrayString);
CA_BSTRGetCString (firstOfPtr, &ptrString);
Let me know if it helps
Best Regards
Luca Gallo
Application Engineer
National Instruments Italy
