Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!bsu-cs!mithomas
From: mithomas@bsu-cs.bsu.edu (Michael Thomas Niehaus)
Newsgroups: comp.sys.mac.programmer
Subject: Changing Mac's Volume: How?
Message-ID: <10068@bsu-cs.bsu.edu>
Date: 1 Sep 89 13:50:15 GMT
Organization: CS Dept, Ball St U, Muncie, Indiana
Lines: 24

The subject says it all:  How do you go about changing the volume from within
an application.  I am doing this right now:

thePRAM = GetSysPPtr();
BitAnd( *(thePRAM->volClik),0x9F );
BitOr( *(thePRAM->volClik),(newVol*256));
WriteParam();

This changes the volume in the parameter RAM.  I know that for sure.  It
also changes the value of the low-memory SPVolCtl to what it should be.
But, the volume doesn't actually change.  The Control Panel shows the volume
as what I set it to, but if I try to make a sound, it will be at the same old
volume.  Unless I click on the Control Panel's volume control (without moving
the slider).  So I assume that the Control Panel is doing something that I
am not.  So what could that be?

Any suggestions would be appreciated.

-Michael

-- 
Michael Niehaus        UUCP: <backbones>!{iuvax,pur-ee}!bsu-cs!mithomas
Apple Student Rep      ARPA:  mithomas@bsu-cs.bsu.edu
Ball State University  AppleLink: ST0374 (from UUCP: st0374@applelink.apple.com)