The WM_SYSCHAR message is posted to the window with the keyboard focus when a WM_SYSKEYDOWN message is translated by the TranslateMessage function. It specifies the character code of a system character key — that is, a character key that is pressed while the alt key is down.
WM_SYSCHAR
chCharCode = (TCHAR) wParam; // character code
lKeyData = lParam; // key data
| Value | Meaning |
|---|---|
| 0–15 | Specifies the repeat count for the current message. The value is the number of times the keystroke was auto-repeated as a result of the user holding down the key. If the keystroke is held long enough, multiple messages are sent. However, the repeat count is not cumulative. |
| 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 1 if the alt key is held down while the key is pressed; otherwise, the value is 0. |
| 30 | Specifies the previous key state. The value is 1 if the key is down before the message is sent, or it is 0 if the key is up. |
| 31 | Specifies the transition state. The value is 1 if the key is being released, or it is 0 if the key is being pressed. |
An application should return zero if it processes this message.
When the context code is zero, the message can be passed to the TranslateAccelerator function, which will handle it as though it were a standard key message instead of a system character-key message. This allows accelerator keys to be used with the active window even if the active window does not have the keyboard focus.
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; the print scrn key; the break key; the numlock key; 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 Accelerators Overview, Keyboard Accelerator Messages, TranslateAccelerator, TranslateMessage, WM_SYSKEYDOWN