The framework calls this member function if CWnd has the input focus and the WM_SYSKEYUP and WM_SYSKEYDOWN messages are translated.

afx_msg void OnSysChar(
   UINT nChar,
   UINT nRepCnt,
   UINT nFlags 


  • nChar
    Specifies the ASCII-character key code of a Control-menu key.

  • nRepCnt
    Specifies the repeat count (the number of times the keystroke is repeated as a result of the user holding down the key).

  • nFlags
    The nFlags parameter can have these values:




    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..


    Specifies the scan code. The value depends on the original equipment manufacturer (OEM)


    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.


    Used internally by Windows.


    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.


    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.


    Specifies the transition state. The value is 1 if the key is being released, or it is 0 if the key is being pressed.


It specifies the virtual key code of the Control-menu key. (For a list of of standard virtual key codes, see Winuser.h)

When the context code is 0, WM_SYSCHAR can pass the WM_SYSCHAR message to the TranslateAccelerator Windows function, which will handle it as though it were a normal key message instead of a system character-key. This allows accelerator keys to be used with the active window even if the active window does not have the input focus.

For IBM Enhanced 101- and 102-key keyboards, enhanced 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 slash (/) and ENTER keys in the numeric keypad. Some other keyboards may support the extended-key bit in nFlags.


This member function is called by the framework to allow your application to handle a Windows message. The parameters passed to your function reflect the parameters received by the framework when the message was received. If you call the base-class implementation of this function, that implementation will use the parameters originally passed with the message and not the parameters you supply to the function.


Header: afxwin.h

See Also


CWnd Class

Hierarchy Chart






CWnd Members