WM_DEADCHAR message

Posted to the window with the keyboard focus when a WM_KEYUP message is translated by the TranslateMessage function. WM_DEADCHAR specifies a character code generated by a dead key. A dead key is a key that generates a character, such as the umlaut (double-dot), that is combined with another character to form a composite character. For example, the umlaut-O character ( ) is generated by typing the dead key for the umlaut character, and then typing the O key.

#define WM_DEADCHAR                     0x0103

Parameters

wParam

The character code generated by the dead key.

lParam

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

Bits	Meaning
0-15	The repeat count for the current message. The value is the number of times the keystroke is autorepeated 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	The scan code. The value depends on the OEM.
24	Indicates 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	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	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	The transition state. The value is 1 if the key is being released, or it is 0 if the key is being pressed.

For more detail, see Keystroke Message Flags.

Return value

An application should return zero if it processes this message.

Remarks

The WM_DEADCHAR message typically is used by applications to give the user feedback about each key pressed. For example, an application can display the accent in the current character position without moving the caret.

Because there is not necessarily a one-to-one correspondence between keys pressed and character messages generated, the information in the high-order word of the lParam parameter is generally not useful to applications. The information in the high-order word applies only to the most recent WM_KEYDOWN message that precedes the posting of the WM_DEADCHAR message.

For enhanced 101- and 102-key keyboards, extended keys are the right ALT and the right 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. Some other keyboards may support the extended-key bit in the lParam parameter.

Requirements

See also

• TranslateMessage
• WM_KEYDOWN
• WM_KEYUP
• WM_SYSDEADCHAR
• Keyboard Input
• About Keyboard Input