Important:
This is retired content. This content is outdated and is no longer being maintained. It is provided as a courtesy for individuals who are still using these technologies. This content may contain URLs that were valid when originally published, but now link to sites or pages that no longer exist.
A version of this page is also available for
4/8/2010

This message is posted to the window with the keyboard focus when a WM_SYSKEYDOWNmessage is translated by the TranslateMessagefunction. It specifies the character code of a system character key — that is, a character key that is pressed while the ALT key is down.

Syntax 

WM_SYSCHAR 
chCharCode = (TCHAR) 
wParam; 

lKeyData = 
lParam;

Parameters

chCharCode

Specifies the character code of the windowmenu key.

lKeyData

Specifies the repeat count, context code, previous key-state flag, and transition-state flag, as shown in the following table.

Value Description

0–15

Specifies the repeat count. The value is the number of times the keystroke is repeated as a result of the user holding down the key.

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.

Return Value

An application should return zero if it processes this message.

Remarks

When the context code is zero, the message can be passed to the TranslateAcceleratorfunction, which will handle it as though it were a standard key message instead of a system character-key message. This enables 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 lKeyDataparameter.

Requirements

Header winuser.h
Windows Embedded CE Windows CE 1.0 and later
Windows Mobile Windows Mobile Version 5.0 and later

See Also