REFERENCE GUIDE

Default actionCommentsNone.16-23(low byte ofhigh-order word)2425-2627-28293031Scan code (OEM-dependent value).Extended key, such as a function keyor a key on the numeric key pad (1 ifit is an extended key, 0 otherwise).Not used.Used internally by Windows.Context code (1 if the ALT key is helddown while the key is pressed, 0otherwise).Previous key state (1 if the key isdown before the message is sent, 0 ifthe key is up).Transition state (1 if the key is beingreleased, 0 if the key is beingpressed).When the context code is zero, the message can be passed to theTranslateAccelerator function, which will handle it as though it were anormal key message instead of a system-key message. This allowsaccelerator keys to be used with the active window even if the activewindow does not have the input focus.For IBM Enhanced 101- and 102-key keyboards, enhanced keys are theright ALT and the right CONTROL keys on the main section of the keyboard;the INSERT, DELETE, HOME, END, PAGE UP, PAGE DOWN and DIRECTION keysin the clusters to the left of the numeric key pad; and the divide (f) andENTER keys in the numeric key pad. Some other keyboards may supportthe extended-key bit in the IParam parameter.WM_SYSCOLORCHANGEThis message specifies a change in one or more system colors. Windowssends the message to all top-level windows when a change is made in thesystem color setting.Parameters wParam Is not used.Default actionIParamIs not used.Windows sends a WM_PAINT message to any window that is affected bya system color change.Chapter 6, Messages directory 689