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From: iand@mullian.ee.mu.OZ.AU (Ian Robert DOBSON)
Newsgroups: comp.sys.mac.programmer
Subject: HELP - Asynchronous Sound Manager Calls
Keywords: sound snd
Message-ID: <6797@munnari.oz.au>
Date: 18 Feb 91 01:20:57 GMT
Sender: news@cs.mu.oz.au
Reply-To: iand@mullian.ee.mu.OZ.AU (Ian Robert DOBSON)
Organization: Dept. of Electrical Engineering, University of Melbourne
Lines: 26

I am writing a program which must be able to play sounds asynchronously
when in both the foreground and background (it's a BBS system - I need
to alert the system operator when a remote user wants to chat)

I have tried using the Sound Manager as follows:

1. Allocated a sound channel
2. Issued a SndPlay call with a TRUE for the 'async' parameter
3. Added a completion callBack routine into the queue.  The callback
   routine sets a global flag saying the sound is finished playing.
4. Go through the main event loop until the sound is finished.
5. Deallocate the sound channel

Trouble is, when the sound is playing and a context switch occurs (eg.
I click on a window from another application) or when After Dark
switches in, the system bombs.

I have seen other applications doing what I want (eg. QuickGIF) so I know
it's possible to do.  Can anybody tell me what is going wrong?


Please send e-mail

Ian R. Dobson
University of Melbourne
iand@mullian.ee.mu.OZ.AU