WM_CHAR

Overview

Group

Quick Info

Windows NT
Yes
Win95
Yes
Win32s
Yes
Import Library
-
Header File
winuser.h
Unicode
No
Platform Notes
None

The WM_CHAR message is posted to the window with the keyboard focus when a WM_KEYDOWN message is translated by the TranslateMessage function. WM_CHAR contains the character code of the key that was pressed.

WM_CHAR

chCharCode = (TCHAR) wParam; // character code

lKeyData = lParam; // key data

Parameters
chCharCode

Value of wParam. Specifies the character code of the key.

lKeyData

Value of lParam. Specifies the repeat count, scan code, extended-key flag, context code, previous key-state flag, and transition-state flag, as shown in the following table:

Value	Description
015	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.
1623	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.
2528	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.

Return Values
An application should return zero if it processes this message.

Remarks
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 lKeyData 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_CHAR 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 lKeyData parameter.