The EN_MAXTEXT notification message is sent when the current text insertion has exceeded the specified number of characters for the edit control. The text insertion has been truncated.
This message is also sent when an edit control does not have the ES_AUTOHSCROLL style and the number of characters to be inserted would exceed the width of the edit control.
This message is also sent when an edit control does not have the ES_AUTOVSCROLL style and the total number of lines resulting from a text insertion would exceed the height of the edit control.
The parent window of the edit control receives this notification message through the WM_COMMAND message.
EN_MAXTEXT idEditCtrl = (int) LOWORD(wParam); // identifier of edit control hwndEditCtrl = (HWND) lParam; // handle of edit control