[color=blue]WM_QUERYENDSESSION[/color]
The WM_QUERYENDSESSION message is sent when the user chooses to end the session or when an application calls the ExitWindows function. If any application returns zero, the session is not ended. The system stops sending WM_QUERYENDSESSION messages as soon as one application returns zero.
After processing this message, the system sends the WM_ENDSESSION message with the wParam parameter set to the results of the WM_QUERYENDSESSION message.
A window receives this message through its WindowProc function.
LRESULT CALLBACK WindowProc(
HWND hwnd, //
handle to window
WM_QUERYENDSESSION, // the message to send
WPARAM wParam, // not used
LPARAM lParam // logoff option
);
[color=blue]Parameters[/color]
[color=blue]wParam [/color]
This parameter is reserved for future use.
[color=blue]lParam [/color]
If this parameter includes ENDSESSION_LOGOFF, the user is logging off. (Note that this parameter is a bit mask. To test for this value, use a bit-wise operation; do not test for equality.)
If this parameter is zero, the system is shutting down.
[color=blue]Return Values[/color]
If an application can terminate conveniently, it should return TRUE; otherwise, it should return FALSE.
[color=blue]Remarks[/color]
By default, the DefWindowProc function returns TRUE for this message.
When an application returns TRUE for this message, it receives the WM_ENDSESSION message and it is terminated, regardless of how the other applications respond to the WM_QUERYENDSESSION message.
[color=blue]Windows Me/98/95:[/color] After all applications return TRUE for this message, they receive the WM_ENDSESSION and they are terminated.