Get IAccessible of UserForm control without reference

Option Explicit

#If Win64 Then
    Private Const PTR_SIZE As LongLong = 8
#Else
    Private Const PTR_SIZE As Long = 4
    Private Enum LongPtr
        [_]
    End Enum
#End If

Private Type GUID
    Data1 As Long
    Data2 As Integer
    Data3 As Integer
    Data4(0 To 7) As Byte
End Type

Private Declare PtrSafe Function DispCallFunc Lib "oleAut32.dll" ( _
    ByVal pvInstance As LongPtr, _
    ByVal offsetinVft As LongPtr, _
    ByVal CallConv As Long, _
    ByVal retTYP As Integer, _
    ByVal paCNT As Long, _
    ByVal paTypes As LongPtr, _
    ByVal paValues As LongPtr, _
    ByVal retVAR As LongPtr _
) As Long

Private Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" ( _
    Destination As Any, _
    Source As Any, _
    ByVal Length As LongPtr _
)


Private Sub UserForm_Initialize()

    Dim DispCallFuncResult As Long
    Dim result As Long
    
    'IID_IAccessible: {618736E0-3C3D-11CF-810C-00AA00389B71}
    'DEFINE_GUID(IID_IAccessible, 0x618736e0, 0x3c3d, 0x11cf, 0x81, 0x0c, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71);
    Dim acc_guid As GUID
    With acc_guid
        .Data1 = &H618736E0
        .Data2 = &H3C3D
        .Data3 = &H11CF
        .Data4(0) = &H81
        .Data4(1) = &HC
        .Data4(2) = &H0
        .Data4(3) = &HAA
        .Data4(4) = &H0
        .Data4(5) = &H38
        .Data4(6) = &H9B
        .Data4(7) = &H71
    End With
    
    Dim pacc As LongPtr

    Dim varTypes(0 To 1) As Integer
    varTypes(0) = 29 ' VT_USERDEFINED
    varTypes(1) = VarType(pacc)

    Dim varPointers(0 To 1) As LongPtr
    varPointers(0) = VarPtr(acc_guid.Data1)
    varPointers(1) = VarPtr(pacc)

    ' Get IAccessible of TextBox1 with call to IUnknown::QueryInterface(REFIID,void**)
    DispCallFuncResult = DispCallFunc(ObjPtr(TextBox1), 0, 4, 3, 2, VarPtr(varTypes(0)), VarPtr(varPointers(0)), VarPtr(result))

    Debug.Print result, DispCallFuncResult
    
    Dim acc As Object
    If pacc <> 0 Then
        CopyMemory acc, ByVal pacc, PTR_SIZE
    End If

    Dim racc As IAccessible ' test only. our acc should equal to racc
    Set racc = TextBox1
    Debug.Print "accValue: " & racc.accValue(0&)
    
    Debug.Assert acc Is racc
    Debug.Print acc.accValue(0&)

End Sub