🚀 go-pugleaf

Date: Mon, 25 Jun 84 12:37:43 pdt
From: Joseph I. Pallas <uw-beaver!pallas@Pescadero>
Subject: Re:  StartSound
To: croft@safe
Cc: info-mac@sumex, sumacc@sumex

	  From: Joseph I. Pallas <pallas@Pescadero>
	  Subject: StartSound
	  To: croft@safe
	  
	  The assembly implementation of StartSound (both the Apple
	  version and yours) has the ASYNC flag commented out.  The
	  effect of this seems to be that calls to StartSound do not
	  return until the specified duration has passed.
	

	From: Bill Croft <croft@safe>
	Subject: Re:  StartSound

	Since there is only one buffer declared in the StartSound
	assembly helper,  Apple probably wanted to reduce confusion and
	made the Write call synchronous.  Otherwise they probably would
	have had to have a "TestSoundDone" routine and/or a
	"WaitSoundDone", etc.

	If you want to do ASYNC IO, then setup your own ParamBlocks and
	use the PBWrite call directly.  There is probably an example of
	this in the SoundLab sample program.

Alas, the SoundLab program is the question, not the answer.  As an
exercise, I transliterated SoundLab into C.  The result works fine
(well, almost), except that SoundLab calls StartSound and expects it to
work asynchronously.  SoundLab, in fact, does implement a sort of
WaitSoundDone (very kludgily) by setting the duration to 1 and doing a
delay loop.  There's no question that the author of SoundLab believed
StartSound was asynchronous.  I'm willing to believe that someone
decided to change that after SoundLab was written, given that the last
date in its code is Jan. 1983; I just wondered whether there was any
explanation for the change.

joe