OpenEuphoria

Re: Windows XP: message box with no other GUI does not work

• Posted by petelomax Feb 22, 2011
• 1633 views

I know Matt has already comitted a fix by invoking InitCommonControlsEx(), but since this came up again... though I hesitate to send anyone off on a pointless wild goose chase...

Last week I stumbled across some code I added to my copy of arwen last September:

if 01 then  -- PL 05/09/2010 (the demo program edita/f.exw failed under exw 
            --                apparently because it didn't open_dll("shell32.dll")... ???) 
        createWindowParams = {dwExStyle,        -- extended style 
                              lpszClassName,    -- window class name 
                              lpszWindowName,   -- window caption or Button text etc.. 
                              dwStyle,          -- window style 
                              x,                -- initial x position 
                              y,                -- initial y position 
                              nWidth,           -- initial x size 
                              nHeight,          -- initial y size 
                              pHwnd,            -- parent window handle 
                              NULL,             -- window menu handle OR user id for child windows 
                              NULL,             -- program instance handle - Legacy of Win16 apps. 0 will work too. 
                              NULL}             -- creation parameters 
--?createWindowParams 
        ePrev = 0 
        while 1 do 
            hwnd = c_func(xCreateWindowEx, createWindowParams) 
            if hwnd!=NULL then exit end if 
--  ERROR_TLW_WITH_WSCHILD = 1406, 
--  ERROR_CANNOT_FIND_WND_CLASS = 1407, 
--  ERROR_CLASS_DOES_NOT_EXIST = 1411, 
            eCode = c_func(xGetLastError,{}) 
            if ePrev=0 
            and (eCode=ERROR_CANNOT_FIND_WND_CLASS or 
                 eCode=ERROR_CLASS_DOES_NOT_EXIST) then 
                ePrev = eCode 
                if not registerClass(classname,0,WndProcCallBack,NULL,NULL,COLOR_BTNFACE+1) then 
                    -- (the [2] is just so you know it's this message not the one above) 
                    FatalErr("Registration[2] of new window class: "& classname &" failed.") 
                end if 
            else 
                printf(1,"Control creation routine failed with error code %d.\n",eCode) 
                return 0 
            end if 
        end while 
 
else -- old code: 
        hwnd = c_func(xCreateWindowEx, { 
                                        dwExStyle,      -- extended style 
                                        lpszClassName,  -- window class name 
                                        lpszWindowName, -- window caption or Button text etc.. 
                                        dwStyle,        -- window style 
                                        x,              -- initial x position 
                                        y,              -- initial y position 
                                        nWidth,         -- initial x size 
                                        nHeight,        -- initial y size 
                                        pHwnd,          -- parent window handle 
                                        NULL,           -- window menu handle OR user id for child windows 
                                        NULL,           -- program instance handle - Legacy of Win16 apps. 0 will work too. 
                                        NULL})          -- creation parameters 
--?hwnd 
        if hwnd=NULL then 
            --?getLastError() 
            ?9/0 
            WarnErr("Control creation routine failed.") 
            return 0 
        end if 
end if 

so if I get an ERROR_CANNOT_FIND_WND_CLASS or ERROR_CLASS_DOES_NOT_EXIST (=1411), I now try registering the unknown class and re-try the CreateWindowEx, at most once.

I cannot see how this could apply to msgbox.e, but someone else might.
Of course I fully accept that precious time is usually better spent fixing things that are still broken

Pete