Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!cs.utexas.edu!sun-barr!ccut!titcca!kddlab!atrpost!atr-la!alain
From: alain@atr-la.atr.co.jp (Alain de Cheveigne)
Newsgroups: comp.sys.mac.programmer
Subject: Re: ROM doesn't unlock Handles (was: ROM unlocks Handles).
Message-ID: <3902@atr-la.atr.co.jp>
Date: 31 Dec 89 06:07:33 GMT
References: <3875@atr-la.atr.co.jp> <4525@helios.ee.lbl.gov> <3888@atr-la.atr.co.jp> <3889@atr-la.atr.co.jp> <2632@draken.nada.kth.se>
Organization: ATR International,Japan
Lines: 49
In-reply-to: d88-jwa@nada.kth.se's message of 27 Dec 89 22:30:22 GMT




In article <2632@draken.nada.kth.se>, d88-jwa@nada.kth.se (Jon Watte) writes:
>In article <3889@atr-la.atr.co.jp> alain@atr-la.atr.co.jp (Alain de Cheveigne) writes:
>>By this reasoning, WindowPtrs should have been Handles, since the user 
>>can open and close them in any order.  

To be precise, I should have written, "allocate and deallocate"
instead of "open and close", since a "closed" window (e.g. hidden with
HideWindow())can still be allocated.  Mais vous m'aviez compris...

>Well, for "historical reasons" they aren't...
>
>A good thing to do is to
>
>...
>  tempH = NewHandle(sizeof(WindowRecord));
>  MoveHHi(tempH);
>  HLock(tempH);
>  theWindow = GetNewWindow(4711, (GrafPtr) *tempH, 0L);
>  SetWRefCon(theWindow, tempH);
>
>...
>
>  tempH = GetWRefCon(theWindow);
>  CloseWindow(theWindow);
>  DisposHandle(tempH);
>
>But, alas, that means you can't use the WRefCon for something else...

Wow!  I always wanted to put a window record in a Handle, but never
dared.  Do you actually sometimes unlock the Handle and let it float?

If you don't, I fail to see the advantage of a non-relocatable block
at the top of the heap over one at the bottom.  

If you do unlock, don't you risk confusing the Window Manager or
Multifinder when the block actually moves?

Using the refcon is not a big problem, because you can make it point
to a structure (preferably relocatable) that contains a field that
points back to your Handle, along with other fields for whatever else
you need to associate with the window.



Alain de Cheveigne
atr-la.atr.co.jp