VBA 64-bit Excel not passing pointers to DLL functions (C++)

Question

I have VBA program running on Excel 64-bit calling some DLL functions (C++). The problem is (apparently) it can't pass pointers to C++ program. The program works with Excel 32-bit.The operating system is Windows 8. For Windows 7 both 32-bit and 64-bit versions of Excel are working well.

C++ :

double test(long* v, long i) 
 {
    if (v == NULL)
        return -88;
    else
        return *((long*)v);
 }

VBA:

Private Declare PtrSafe Function hamid_test Lib "...\CVode.dll" (ByVal v As LongPtr, ByVal i As Long) As Double

 Dim x As LongLong
 Dim z As Double
 z = test(x, 1)

It returns -88.

Try Dim x As LongPtr

kaybee99
– kaybee99

2015-05-27 16:54:00 +00:00
Commented May 27, 2015 at 16:54 — kaybee99
– kaybee99, Commented May 27, 2015 at 16:54

kaybee99 · Accepted Answer · 2015-05-28 11:02:47Z

1

Dim x As LongPtr
Dim z As Double
z = test(x, CLng(1))

LongPtr evaluates to Long in 32-Bit environments and to LongLong in 64-Bit environments so defining x as such should work.

Addtionally, CLng will ensure 1 is evaluated as a Long type. If this is not added VBA will assume you mean Integer

answered May 28, 2015 at 11:02

kaybee99

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