On Feb 8, 2005, at 12:07 AM, John M McIntosh wrote:

> Found it.
>
> In the Unix code  sqUnixSoundMacOSX.c
>
>  OSStatus bufferDataProc(AudioConverterRef inAudioConverter, UInt32  
> *ioDataSize, void  **outData, void  *context)
> {
> ...
>   if (!n1)
>     {
>        char empty[256];
>       *ioDataSize= min(256, *ioDataSize);
>       *outData= (void *)empty;
> #    if (DEBUG)
>       putchar('-');  fflush(stdout);
> #    endif
>     }
>   ...
>
> One should NOT assume that char empty[256] will in fact result in a  
> byte string containing 256 zero bytes, rather we get something  
> not-zero, thus a buzz.
> I also wonder about the *outData = (void *) empty if *ioDataSize is  
> actually < 256 bytes.
> Seems to me one should do a memset(outData,0,*ioDataSize);  to ensure  
> zeros and not walking off the end of a small outData buffer...

Oops not quite correct one is setting the void **outData so we just  
need to point to a zero byte buffer containing enough zeros.  Still  
this is
a local variable returned to the caller and the processed, wonder who  
or where the stack memory lurks. Mmm perhaps it should become a
static zero byte structure somewhere.

--
======================================================================== 
===
John M. McIntosh <johnmci at smalltalkconsulting.com> 1-800-477-2659
Corporate Smalltalk Consulting Ltd.  http://www.smalltalkconsulting.com
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