Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.271,1.272

Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.271,1.272

[Abramo Bagnara]

Jaroslav Kysela ha scritto:
> Update of /cvsroot/alsa/alsa-lib/src/pcm
> In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv19814
> 
> Modified Files:
> 	pcm.c 
> Log Message:
> Fixed return comment for *near() functions
> 
> Index: pcm.c
> ===================================================================
> RCS file: /cvsroot/alsa/alsa-lib/src/pcm/pcm.c,v
> retrieving revision 1.271
> retrieving revision 1.272
> diff -u -r1.271 -r1.272
> --- pcm.c	23 Feb 2004 10:34:17 -0000	1.271
> +++ pcm.c	1 Mar 2004 08:53:50 -0000	1.272
> @@ -3418,7 +3418,7 @@
>   * \param pcm PCM handle
>   * \param params Configuration space
>   * \param val target channels count, returned chosen channels count
> - * \return chosen channels count
> + * \return 0 otherwise a negative error code if configuration space would become empty

*near() functions semantic cannot return error by design.

Taken for granted that configuration space on entry of function is not 
empty how it can become empty if I ask for *nearest* value?

Obviously at least one configuration exists, then in the worst case such 
value is returned.

Do you agree?


-- 
Abramo Bagnara                       mailto:abramo.bagnara@tin.it

Opera Unica                          Phone: +39.0546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy


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Re: Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.271,1.272

[Paul Davis]

>Taken for granted that configuration space on entry of function is not 
>empty ....

can this be taken for granted?


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Re: Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.271,1.272

[Clemens Ladisch]

Abramo Bagnara wrote:
> Jaroslav Kysela ha scritto:
> > Log Message:
> > Fixed return comment for *near() functions
> >
> > + * \return 0 otherwise a negative error code if configuration space would become empty
>
> *near() functions semantic cannot return error by design.
>
> Taken for granted that configuration space on entry of function is not
> empty how it can become empty if I ask for *nearest* value?
>
> Obviously at least one configuration exists, then in the worst case such
> value is returned.

It may be possible that other errors than an empty configuration space
could occur.  For example, future ALSA versions might want to fail if
an hotplug device has been unpluggeed, or the configuration space
could have been reduced due to some outside influence.

I don't think we can guarantee that this function never ever fails.

Maybe we should simply drop the "if configuration space would become
empty".


Regards,
Clemens




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Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.271,1.272

[Jaroslav Kysela]

On Mon, 1 Mar 2004, Abramo Bagnara wrote:

> Jaroslav Kysela ha scritto:
> > Update of /cvsroot/alsa/alsa-lib/src/pcm
> > In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv19814
> > 
> > Modified Files:
> > 	pcm.c 
> > Log Message:
> > Fixed return comment for *near() functions
> > 
> > Index: pcm.c
> > ===================================================================
> > RCS file: /cvsroot/alsa/alsa-lib/src/pcm/pcm.c,v
> > retrieving revision 1.271
> > retrieving revision 1.272
> > diff -u -r1.271 -r1.272
> > --- pcm.c	23 Feb 2004 10:34:17 -0000	1.271
> > +++ pcm.c	1 Mar 2004 08:53:50 -0000	1.272
> > @@ -3418,7 +3418,7 @@
> >   * \param pcm PCM handle
> >   * \param params Configuration space
> >   * \param val target channels count, returned chosen channels count
> > - * \return chosen channels count
> > + * \return 0 otherwise a negative error code if configuration space would become empty
> 
> *near() functions semantic cannot return error by design.
> 
> Taken for granted that configuration space on entry of function is not 
> empty how it can become empty if I ask for *nearest* value?
> 
> Obviously at least one configuration exists, then in the worst case such 
> value is returned.
> 
> Do you agree?

Ok, I replace the phrase with "if configuration space is empty".

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project, SuSE Labs


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