关机的消息

关机的消息是：WM_QUERYENDSESSION WM_QUERYENDSESSION
nSource = (UINT) wParam; // source of end-session request
fLogOff = lParam // logoff flag
　
Parameters
nSource
Reserved for future use.
fLogOff
Value of lParam. Indicates whether the user is logging off or shutting down the system. Supported values include: ENDSESSION_LOGOFF.
Return Values
If an application can terminate conveniently, it should return TRUE; otherwise, it should return FALSE.
　
当执行exitwindows函数时
它会发送一个WM_QUERYENDSESSION消息给所有正在运行的程序。