Fast string appending in VB6

[plenderj]

I've had this code lying around, so thought I would post it here.
It is ( well, should be ) a lot faster than VB's internal string appending & operator.

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long)
 
Private Sub appendToString(ByRef strBuff As String, ByVal strStringToAppend As String)
    CopyMemory ByVal StrPtr(strBuff) + LenB(strBuff), ByVal StrPtr(strStringToAppend), LenB(strStringToAppend)
End Sub
 
'' Sample Usage
''
Private Sub Form_Load()
    Dim i As Long, x As String: x = "a"
    For i = 0 To 10000
        appendToString x, CStr(i)
    Next
    MsgBox x
End Sub