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From: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Newsgroups: comp.sys.amiga.tech
Subject: Re: following the sliding prop gadget
Summary: You want CloseWindowSafely()
Message-ID: <7288@well.UUCP>
Date: 4 Oct 88 08:33:09 GMT
References: <2877@mtuxo.att.com> <4875@cbmvax.UUCP> <7263@well.UUCP> <2937@mtuxo.att.com>
Reply-To: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Distribution: na
Organization: Hole Earth 'Lectronic Loss (or words to that effect)
Lines: 64
Quote: "I plan to live forever -- or die trying."  -- Vila

In article <2937@mtuxo.att.com> tas@mtuxo.att.com (XMPC2-T.SKROBALA) writes:
>I have the LockIBase()
>there because all my windows share a common IDCMP port, and I want to
>make sure that I don't process any messages left over from windows that have
>been closed, so I check any incoming message's IDCMPWindow to make sure
>that it still exists.  I'm not terribly satisfied with this approach
>(especially now that it's obviously causing me problems), and I've gotten
>the idea here that there is a way to flush all of a window's pending messages
>when it is closed.  Is this as simple as installing a GetMsg() loop before
>CloseWindow(), or is there more to it?
>
	You want the routine CloseWindowSafely():

--------
/* CloseWindowSafely()
*       This module should be used whenever you are sharing an IDCMP
* message port with more than one window.  Rather than calling CloseWindow(),
* you should use CloseWindowSafely().  This will keep Intuition from
* Guru Meditation, and thus is considered a good thing.  You should still
* use CloseWindow for the very last window you close.
*       The reason this is needed is because Intuition will re-claim
* any outstanding messages for a window when the window is closed.  But...
* it can't take them out of your message port.  Thus, you will receive
* invalid messages and bad things will happen.  Very bad things.
*       This code is a slightly condensed version of the same routine
* written by Neil Katin of Amiga for the April '86 Commodore Developers
* Newsletter, Amiga Mail (tm).
*/
#include <exec/types.h>
#include <intuition/intuition.h>

void 
CloseWindowSafely (win)
register struct Window  *win;
{
	register struct IntuiMessage *msg;
	register struct IntuiMessage *succ;
	register struct MsgPort *mp = (struct MsgPort *) win -> UserPort;

	Forbid ();

	msg = (struct IntuiMessage *) mp -> mp_MsgList.lh_Head;

	while (succ = (struct IntuiMessage *) msg -> ExecMessage.mn_Node.ln_Succ) {
		if (msg -> IDCMPWindow == win) {
			Remove (msg);
			ReplyMsg (msg);
		}
		msg = succ;
	}
	win -> UserPort = NULL;
	ModifyIDCMP (win, 0L);
	Permit ();
	CloseWindow (win);
}
--------

	Enjoy.

_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
Leo L. Schwab -- The Guy in The Cape	INET: well!ewhac@ucbvax.Berkeley.EDU
 \_ -_		Recumbent Bikes:	UUCP: pacbell > !{well,unicom}!ewhac
O----^o	      The Only Way To Fly.	      hplabs / (pronounced "AE-wack")
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