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Path: utzoo!utgpu!water!watnot!watmath!clyde!cbatt!ihnp4!ptsfa!well!ewhac
From: ewhac@well.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: gameport.device
Message-ID: <2679@well.UUCP>
Date: Sun, 1-Mar-87 05:43:51 EST
Article-I.D.: well.2679
Posted: Sun Mar  1 05:43:51 1987
Date-Received: Mon, 2-Mar-87 06:36:16 EST
References: <292@umbc3.UMD.EDU> <13567@sun.uucp>
Reply-To: ewhac@well.UUCP (Leo 'Bols Ewhac' Schwab)
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 72
Keywords: gameport joystick cleanup arrrrgggg

In article <13567@sun.uucp> cmcmanis@sun.uucp (Chuck McManis) writes:
>In article <292@umbc3.UMD.EDU>, chiafari@umbc3.UMD.EDU (frank chiafari) writes:
>[actually he is ghost writing for eric messick]
>> ARRRRRRRGGGGGGGGG!!!!!!!
>> Has anyone gotten the gameport.device to work?  I've gotten entirely too
>> frustrated with this.  My problem goes something like this:
>  ... He goes on to describe the problem ...
>> 
>> I think that's about all I can say...  Code follows...  Any suggestions
>> would be appreciated...  MAIL them (for GOD'S SAKE!) and if there's
>> interest, I'll post my eventual solution.
>> 
>> 			-eric messick
>   ... and lots of code followed ...
>
>Sorry for posting this to everyone unfortunately frank's address bounced
>back faster than greased lightning. My advice to Eric and Frank and
>anyone else doing exec level stuff on the Amiga :
>	* Reply to your messages! *
>When someone sends you a message, be it exec, intuition, or some user
>task, you sould reply to it with ReplyMsg() [.....]
>      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

	NO NO NO NO NO!!!  You DON'T reply to everybody.  This is how it
works.

	All I/O on the Amiga is implemented as message passing.  When you
want the I/O system to do something, you create a message packet, open the
device, and send your requests to it.

	When the I/O driver has completed your request, it lets you know by
replying the message to a reply port which you've created.  Note that it is
the I/O DRIVER that is replying.  It is replying because you sent the
original message.

	DoIO() is a synchronous I/O call; it sends the I/O request to the
driver and waits for it to complete.  SendIO() is asynchronous; it passes
the request to the driver, and returns control to you.  WaitIO() waits for a
particular I/O request to complete.  If you wanted to do interleaved I/O
(for example, asking for a disk block that you know you're going to need
eventually, but you can do some computing in the meantime), then you'd send
the request using SendIO(), do some other stuff for a while, then wait for
the I/O to complete (if it hasn't already) with WaitIO().  BeginIO() is a
low-level version of SendIO().

	As always, never touch the message data while the I/O request is
still outstanding, since the I/O driver owns that data for as long as it has
it.

	The gameport is a device, so these rules apply.  I haven't stared at
the posted code, so I don't know what the problem is.

	For the sake of completeness, Intuition is a totally different
animal.  Intuition is not an I/O driver, it's a sort of application.
You don't send requests (messages) to Intuition, Intuition sends messages to
YOU.  That's why, when you get an IntuiMessage, you should reply it as soon
as you can (after you've copied all the relevant data into private
variables).

	Hope this helps.

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