use this to do a fast copy
Private Declare Sub CopyMemory Lib "kernel32" Alias _
"RtlMoveMemory" (Destination As Any, Source As Any, _
ByVal Length As Long)
Public Sub MemAppend(mDest() As Byte, Source1() As Byte, source2() As Byte)
Dim i As Integer
CopyMemory mDest(0), Source1(0), 2
CopyMemory mDest(2), source2(0), 2
For i = 0 To UBound(mDest)
Debug.Print mDest(i)
Next
End Sub
Public Sub test()
Dim a(1) As Byte
Dim b(1) As Byte
Dim c(3) As Byte
a(0) = 1
a(1) = 2
b(0) = 3
b(1) = 4
MemAppend c, a, b
End Sub