Re: [PATCH] coreaudio: Always return 0 in handle_voice_change

[Christian Schoenebeck <qemu_oss@crudebyte.com>]

On Sonntag, 6. März 2022 11:54:00 CET Akihiko Odaki wrote:
> On 2022/03/06 19:49, Christian Schoenebeck wrote:
> > On Sonntag, 6. März 2022 07:39:49 CET Akihiko Odaki wrote:
> >> MacOSX.sdk/System/Library/Frameworks/CoreAudio.framework/Headers/AudioHar
> >> dwa re.h
> >> 
> >> says:
> >>> The return value is currently unused and should always be 0.
> > 
> > Where does it say that, about which macOS functions? There are quite a
> > bunch of macOS functions involved in init_out_device(), and they all have
> > error pathes in init_out_device(), and they still will have them after
> > this patch.
> > 
> > And again, I'm missing: this as an improvement because? Is this a user
> > invisible improvement (e.g. removing redundant branches), or is this a
> > user
> > visible improvement, i.e. does it fix a misbehaviour? In case of the
> > latter, which misbehaviour did you encounter?
> 
> handle_voice_change itself is a callback.
> It is invisible for a user since "the return value is currently unused".

Then the commit log should be more specific and say something like:

"
handle_voice_change() is a CoreAudio callback function as of CoreAudio type 
'AudioObjectPropertyListenerProc', and for the latter MacOSX.sdk/System/
Library/Frameworks/CoreAudio.framework/Headers/AudioHardware.h
says 'The return value is currently unused and should always be 0.'.
"

Nevertheless, personally I would not change that, but I won't object either.

I read it like "The CoreAudio subsystem of macOS currently ignores the result 
of your callback, and for that reason simply return 0 for now.". It does not 
say "you must not return anything else than 0". ATM it simply does not matter 
what you return here.

Best regards,
Christian Schoenebeck