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From: johnson@su-russell.ARPA (Mark Johnson)
Newsgroups: comp.sys.mac
Subject: VBL tasks and LSC
Message-ID: <325@su-russell.ARPA>
Date: Mon, 20-Jul-87 13:02:46 EDT
Article-I.D.: su-russe.325
Posted: Mon Jul 20 13:02:46 1987
Date-Received: Tue, 21-Jul-87 05:11:54 EDT
Reply-To: johnson@csli.stanford.edu (Mark Johnson)
Organization: Stanford University, CSLI
Lines: 25
Summary: Should ProcPtr be typedefed as int (*ProcPtr)() ??

**

Thanks to all of you who suggested looking at TN 19 for avoiding
clicks in sound generation, and those of you who warned that
following out the instructions of TN 19 might not be so easy using
LSC.

Very true.  The machine consistently bombed whenever I put any
LSC function on to the vertical retrace task queue.  After some
experimentation, I found the following declaration in MacTypes.h

typedef int (*ProcPtr)() ;

Is this right?  Surely a procedure should return nothing, rather than an int?
Replace this with

typedef void (*ProcPtr)() ;

the bomb disappears and I get clear, clickless sounds!

Is this a bug?

Mark

Mark Johnson, CSLI and Dept. of Linguistics, Stanford University.