Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!apple!oliveb!amiga!jimm
From: jimm@amiga.UUCP (Jim Mackraz)
Newsgroups: comp.sys.amiga.tech
Subject: CloseWindowSafely
Message-ID: <3719@amiga.UUCP>
Date: 6 Apr 89 00:58:23 GMT
Reply-To: jimm@amiga.UUCP (Jim Mackraz)
Organization: Commodore-Amiga Inc, Los Gatos CA
Lines: 88

So, I found my copy of CloseWindowSafely(), so I thought I'd toss it
out there for those who haven't got it.  I apologize to those who
asked for me to mail it to them and got no response.  I knew it
was around somewhere.

Some people think that this function should test for NULL window pointer.  Bah.

--------------------- cut here --------------------------------
/* CloseWindowSafely.c -- use like crazy
 * Author: Neil Katin (edited by Jim Mackraz)
 */

#include "exec/types.h"
#include "exec/nodes.h"
#include "exec/lists.h"
#include "exec/ports.h"
#include "intuition/intuition.h"

/* this function closes an Intuition window
 * that shares a port with other Intuition
 * windows (or other compatible IPC).
 *
 * It is careful to set the window's UserPort to
 * null before closing, and to reply to
 * any messages that might be pending.
 */

CloseWindowSafely( win )
struct Window *win;
{
    /* we forbid here to keep out of race conditions with Intuition */
    Forbid();

    /* send back any messages for this window 
     * that have not yet been processed
     */
    StripIntuiMessages( win->UserPort, win );

    /* clear UserPort so Intuition will not free it */
    win->UserPort = NULL;

    /* tell inuition to stop sending more messages */
    ModifyIDCMP( win, 0L );

    /* turn tasking back on */
    Permit();

    /* and really close the window */
    CloseWindow( win );
}


/* Remove and reply any IntuiMessages hanging off of a port
 * which were addressed to a particular window.
 * Note that technique does not rely on ln_Succ of a message
 * after it has been replied.
 */
StripIntuiMessages( mp, win )
struct MsgPort *mp;
struct Window *win;
{
    struct IntuiMessage *msg;
    struct Node *succ;

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

    while( succ = msg->ExecMessage.mn_Node.ln_Succ ) {

	if( msg->IDCMPWindow ==  win ) {
	    /* Intuition is about to rudely free this message.
	     * Make sure that we have politely sent it back.
	     */
	    Remove( msg );

	    ReplyMsg( msg );
	}
	    
	msg = (struct IntuiMessage *) succ;
    }
}

enjoy
	jimm
-- 
Jim Mackraz, I and I Computing	   	"Like you said when we crawled down
{cbmvax,well,oliveb}!amiga!jimm          from the trees: We're in transition."
							- Gang of Four
Opinions are my own.  Comments are not to be taken as Commodore official policy.