Get All Running Excel Instances By Windows Handle (not ROT)

Very interesting code over at Florent Breheret's SeleniumBasic

This caught my eye.

Private Declare PtrSafe Function FindWindowExA Lib "user32.dll" ( _
  ByVal hwndParent As LongPtr, _
  ByVal hwndChildAfter As LongPtr, _
  ByVal lpszClass As String, _
  ByVal lpszWindow As String) As Long

Private Declare PtrSafe Function AccessibleObjectFromWindow Lib "oleacc.dll" ( _
  ByVal hwnd As LongPtr, _
  ByVal dwId As Long, _
  ByRef riid As Any, _
  ByRef ppvObject As IAccessible) As Long


''
' Returns all the active instances of Excel
''
Public Function GetExcelInstances() As Collection
  Dim guid&(0 To 4), app As Object, hwnd
  guid(0) = &H20400
  guid(1) = &H0
  guid(2) = &HC0
  guid(3) = &H46000000
  
  Set GetExcelInstances = New Collection
  Do
    hwnd = FindWindowExA(0, hwnd, "XLMAIN", vbNullString)
    If hwnd = 0 Then Exit Do
    hwnd = FindWindowExA(hwnd, 0, "XLDESK", vbNullString)
    If hwnd Then
      hwnd = FindWindowExA(hwnd, 0, "EXCEL7", vbNullString)
      If hwnd Then
        If AccessibleObjectFromWindow(hwnd, &HFFFFFFF0, guid(0), app) = 0 Then
          GetExcelInstances.Add app.Application
        End If
      End If
    End If
  Loop
End Function