Public Function GetFileFullPath(ByVal hFile As Long) As String
...
HeapFree hHeap, 0, pName
...
End Function
 

Public Function GetFileFullPath(ByVal hFile As Long) As String
    Dim hHeap As Long, dwSize As Long, objName As UNICODE_STRING, pName As Long
    Dim ntStatus As Long, i As Long, strDrives As String, strArray() As String
    Dim dwDriversSize As Long, strDrive As String, strTmp As String, strTemp As String
    On Error GoTo ErrHandle
    hHeap = GetProcessHeap
    pName = HeapAlloc(hHeap, HEAP_ZERO_MEMORY, &H1000)
    ntStatus = NtQueryObject(hFile, ObjectNameInformation, pName, &H1000, dwSize)
    If (NT_SUCCESS(ntStatus)) Then
        i = 1
        Do While (ntStatus = STATUS_INFO_LEN_MISMATCH)
            pName = HeapReAlloc(hHeap, HEAP_ZERO_MEMORY, pName, &H1000 * i)
            ntStatus = NtQueryObject(hFile, ObjectNameInformation, pName, &H1000, ByVal 0)
            i = i + 1
        Loop
    End If
    HeapFree hHeap, 0, pName
    strTemp = String(512, Chr(0))
    lstrcpyW strTemp, pName + Len(objName)
 

NtQueryObject(hFile, ObjectNameInformation, 0, 0, &dwSize)  ( C++, Pasando el puntero a dwSize )