An application sends an EM_GETRECT message to retrieve the formatting rectangle of an edit control. The formatting rectangle is the limiting rectangle of the text. The limiting rectangle is independent of the size of the edit-control window.
EM_GETRECT wParam = 0; // not used; must be zero lParam (LPARAM) (LPRECT) lprc; // address of structure for rectangle
The return value is not a meaningful value.
You can modify the formatting rectangle of a multiline edit control by using the EM_SETRECT and EM_SETRECTNP messages.