Places a message in the message queue and then returns
#include <WinAPISysWin.au3>
_WinAPI_PostMessage ( $hWnd, $iMsg, $wParam, $lParam )
| $hWnd | Identifies the window whose window procedure will receive the message. If this parameter is 0xFFFF (HWND_BROADCAST), the message is sent to all top-level windows in the system, including disabled or invisible windows, overlapped windows, and pop-up windows; but the message is not sent to child windows. |
| $iMsg | Specifies the message to be sent |
| $wParam | First message parameter |
| $lParam | Second message parameter |
| Success: | True |
| Failure: | False, call _WinAPI_GetLastError() to get extended error information |
Search PostMessage in MSDN Library.