OpenEuphoria

Re: How detect that Windows is shutting down?

• Posted by ghaberek (admin) Aug 04, 2012
• 1689 views

If you are writing a Win32Lib application, you can use w32HEvent to catch the WM_QUERYENDSESSION event. If you want to cancel the shutdown, you can call returnValue(w32False), but as Microsoft states in their documentation, "it is good practice to respect the user's actions."

constant 
    WM_QUERYENDSESSION = #0011 
 
constant 
    -- possible values for lParam 
    ENDSESSION_CLOSEAPP = #00000001, 
    ENDSESSION_CRITICAL = #40000000, 
    ENDSESSION_LOGOFF   = #80000000  
 
procedure Main_onEvent( integer pSelf, integer pEvent, sequence pParams ) 
 
    atom uMsg   = pParams[1] 
--  atom wParam = pParams[2] -- (unused) 
    atom lParam = pParams[3] 
 
    if uMsg = WM_QUERYENDSESSION then 
 
        switch lParam do 
 
            case ENDSESSION_CLOSEAPP then 
 
                -- The application is using a file that must be replaced, the 
                -- system is being serviced, or system resources are exhausted.  
 
            case ENDSESSION_CRITICAL then 
 
                -- The application is forced to shut down. 
 
            case ENDSESSION_LOGOFF then 
 
                -- The user is logging off. 
 
        end switch 
 
    end if 
 
end procedure 
setHandler( Main, w32HEvent, routine_id("Main_onEvent") ) 

-Greg