Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" _
       (ByVal lpPrevWndFunc As Long, _
        ByVal hWnd As Long, _
        ByVal Msg As Long, _
        ByVal wParam As Long, _
        ByVal lParam As Long) As Long
Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _
       (ByVal hWnd As Long, _
        ByVal nIndex As Long, _
        ByVal dwNewLong As Long) As Long

Const GWL_WNDPROC As Long = -4
Const WM_TEST = 7777

Public lpPrevWndProc As Long
Public gHW As Long

Public Sub Hook()
lpPrevWndProc = SetWindowLong(gHW, GWL_WNDPROC, _
                                 AddressOf WindowProc)
End Sub

Public Sub UnHook()
    Dim lngReturnValue As Long
    lngReturnValue = SetWindowLong(gHW, GWL_WNDPROC, lpPrevWndProc)
End Sub

Function WindowProc(ByVal hw As Long, _
                    ByVal uMsg As Long, _
                    ByVal wParam As Long, _
                    ByVal lParam As Long) As Long
    Select Case uMsg
        Case WM_TEST '원하는 메세지
            MsgBox "메세지도착"
        Case Else
            WindowProc = CallWindowProc(lpPrevWndProc, hw, _
                                       uMsg, wParam, lParam)
    End Select
End Function

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