The WM_KEYUP message is posted to the window with the keyboard focus when a nonsystem key is released. A nonsystem key is a key that is pressed when the alt key is not pressed, or a keyboard key that is pressed when a window has the keyboard focus.
WM_KEYUP
nVirtKey = (int) wParam; // virtual-key code
lKeyData = lParam; // key data
Value | Description |
---|---|
0–15 | Specifies the repeat count for the current message. The value is the number of times the keystroke is auto-repeated as a result of the user holding down the key. The repeat count is always one for a WM_KEYUP message. |
16–23 | Specifies the scan code. The value depends on the original equipment manufacturer (OEM). |
24 | Specifies whether the key is an extended key, such as the right-hand alt and ctrl keys that appear on an enhanced 101- or 102-key keyboard. The value is 1 if it is an extended key; otherwise, it is 0. |
25–28 | Reserved; do not use. |
29 | Specifies the context code. The value is always 0 for a WM_KEYUP message. |
30 | Specifies the previous key state. The value is always 1 for a WM_KEYUP message. |
31 | Specifies the transition state. The value is always 1 for a WM_KEYUP message. |
An application should return zero if it processes this message.
The DefWindowProc function sends a WM_SYSCOMMAND message to the top-level window if the f10 key or the alt key was released. The wParam parameter of the message is set to SC_KEYMENU.
For enhanced 101- and 102-key keyboards, extended keys are the right alt and ctrl keys on the main section of the keyboard; the ins, del, home, end, page up, page down and arrow keys in the clusters to the left of the numeric keypad; and the divide (/) and enter keys in the numeric keypad. Other keyboards may support the extended-key bit in the lKeyData parameter.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Requires version 1.0 or later.
Header: Declared in winuser.h.
Keyboard Input Overview, Keyboard Input Messages, DefWindowProc, WM_KEYDOWN, WM_SYSCOMMAND