EM_EMPTYUNDOBUFFER
wParam = 0; /* not used, must be zero */
lParam = 0L; /* not used, must be zero */
An application sends an EM_EMPTYUNDOBUFFER message to reset (clear) the undo flag of an edit control. The undo flag is set whenever an operation within the edit control can be undone.
This message has no parameters.
This message does not return a value.
The undo flag is automatically cleared whenever the edit control receives a WM_SETTEXT or EM_SETHANDLE message.
This example resets the undo flag of an edit control:
SendDlgItemMessage
(hdlg, ID_MYEDITCONTROL, EM_EMPTYUNDOBUFFER, 0, 0L);