Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!cbmvax!ken
From: ken@cbmvax.commodore.com (Ken Farinsky - CATS)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Simple Audio question
Message-ID: <16603@cbmvax.commodore.com>
Date: 17 Dec 90 18:52:21 GMT
References: <8GG^X6$@rpi.edu>
Reply-To: ken@cbmvax.commodore.com (Ken Farinsky - CATS)
Organization: Commodore, West Chester, PA
Lines: 40

In article <8GG^X6$@rpi.edu> peck@ral.rpi.edu (Joseph Peck) writes:
>
>...how to correctly select an audio channel for playing a sound.
>
>I get warnings when I compile my program...I select the channel with:
>
>AIOptr->ioa_Request.io_Unit = #;  /* where # is either 1,2,3 or 4. */
>
>Joe Peck peck@ral.rpi.edu

I'm not the audio expert, but I'll try to answer your questions.
Looking through the RKM (Libs&Devs) in the Audio Device section, I found:

p610:  You specify the channel that you want to use by setting the
appropriate bits in the ioa_Request.io_Unit field...

from p615, it looks like the bits are set up as follows:

	CHANNEL_0	(1<<0)
	CHANNEL_1	(1<<1)
	CHANNEL_2	(1<<2)
	CHANNEL_3	(1<<3)

Also, from page 614:  If the allocation succeeds, the audio device
will return the channels that you now own in the lower four bits
of the ioa_Request.io_Unit field...So I would guess that you don't
use numbers like 1,2,3 or 4.

So, even though the field is a pointer, you have to put bit values into
it.  Try something like:

	AIOptr->ioa_Request.io_Unit = (struct Unit *)(CHANNEL_0);

Also, remember to mask out any unused bits when checking the value of
this variable and to set unused bits to zero when setting this variable.
-- 
--
Ken Farinsky - CATS - (215) 431-9421 - Commodore Business Machines
uucp: ken@cbmvax.commodore.com   or  ...{uunet,rutgers}!cbmvax!ken
bix:  kfarinsky