Problem calling C DLL function from VBA

[Maximus]

I need to call a DLL function from Access using VBA. The prototype for the
DLL function is

int __stdcall myFunction(const char* data,
int rows, int cols, int sl, int fullsize,
double aspect_ratio,
double y,
void** ppResult);

The one I declared in Access:

Private Declare Function DllImport_myFunction _
Lib "myFunctionDLL.dll" _
Alias "myFunction" _
(ByVal data As String, _
ByVal rows As Long, _
ByVal cols As Long, _
ByVal sl As Long, _
ByVal fullsize As Long, _
ByVal aspectRatio As Double, _
ByVal y As Double, _
ByRef handle As Long)

When I try to call from Access, Access crashed with an access violation. I
placed a breakpoint in the first statement of the DLL function, but it was
not hit.

Is the declaration incorrect?

 

[Chirag]

The function return is missing (and hence Variant is being assumed). The
last line of the declaration in Access should be:
ByRef handle As Long) As Long

See if this helps.

- Chirag

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