Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.227,1.228

Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.227,1.228

[Abramo Bagnara]

Jaroslav Kysela wrote:
> 
> Added ommited clear() functions
> 
> Index: pcm.c
>  /**
> + * \brief clear snd_pcm_hw_params_t structure
> + * \param obj pointer to structure
> + */
> +void snd_pcm_hw_params_clear(snd_pcm_hw_params_t *obj)
> +{
> +       assert(obj);
> +       memset(obj, 0, snd_pcm_hw_params_sizeof());
> +}

Why that _clear functions?
What's the expected semantic for "clear"?

When we designed new API I took in consideration them, but the lack of
usefulness and the ambiguity of semantic has pushed me to avoid them.


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

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy


-------------------------------------------------------
This sf.net email is sponsored by: Influence the future 
of Java(TM) technology. Join the Java Community 
Process(SM) (JCP(SM)) program now. 
http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0002en

Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.227,1.228

[Jaroslav Kysela]

On Wed, 23 Oct 2002, Abramo Bagnara wrote:

> Jaroslav Kysela wrote:
> > 
> > Added ommited clear() functions
> > 
> > Index: pcm.c
> >  /**
> > + * \brief clear snd_pcm_hw_params_t structure
> > + * \param obj pointer to structure
> > + */
> > +void snd_pcm_hw_params_clear(snd_pcm_hw_params_t *obj)
> > +{
> > +       assert(obj);
> > +       memset(obj, 0, snd_pcm_hw_params_sizeof());
> > +}
> 
> Why that _clear functions?
> What's the expected semantic for "clear"?
> 
> When we designed new API I took in consideration them, but the lack of
> usefulness and the ambiguity of semantic has pushed me to avoid them.

Well, you're right that the name is misleading, but wouldn't be good to 
let to reuse a structure? Perhaps, _init suffix is better.

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project  http://www.alsa-project.org
SuSE Linux    http://www.suse.com



-------------------------------------------------------
This sf.net email is sponsored by: Influence the future 
of Java(TM) technology. Join the Java Community 
Process(SM) (JCP(SM)) program now. 
http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0002en

Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.227,1.228

[Jaroslav Kysela]

On Wed, 23 Oct 2002, Jaroslav Kysela wrote:

> On Wed, 23 Oct 2002, Abramo Bagnara wrote:
> 
> > Jaroslav Kysela wrote:
> > > 
> > > Added ommited clear() functions
> > > 
> > > Index: pcm.c
> > >  /**
> > > + * \brief clear snd_pcm_hw_params_t structure
> > > + * \param obj pointer to structure
> > > + */
> > > +void snd_pcm_hw_params_clear(snd_pcm_hw_params_t *obj)
> > > +{
> > > +       assert(obj);
> > > +       memset(obj, 0, snd_pcm_hw_params_sizeof());
> > > +}
> > 
> > Why that _clear functions?
> > What's the expected semantic for "clear"?
> > 
> > When we designed new API I took in consideration them, but the lack of
> > usefulness and the ambiguity of semantic has pushed me to avoid them.
> 
> Well, you're right that the name is misleading, but wouldn't be good to 
> let to reuse a structure? Perhaps, _init suffix is better.

I got it. The initialization makes no sense for these structures.
I required this action for an internal function, but it should not be 
visible. Ok, I'll remove it. Thank you for the correction.

						Jaroslav

-----
Jaroslav Kysela <perex@suse.cz>
Linux Kernel Sound Maintainer
ALSA Project  http://www.alsa-project.org
SuSE Linux    http://www.suse.com



-------------------------------------------------------
This sf.net email is sponsored by: Influence the future 
of Java(TM) technology. Join the Java Community 
Process(SM) (JCP(SM)) program now. 
http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0002en

Re: [alsa-cvslog] CVS: alsa-lib/src/pcm pcm.c,1.227,1.228

[Abramo Bagnara]

Jaroslav Kysela wrote:
> 
> On Wed, 23 Oct 2002, Abramo Bagnara wrote:
> 
> > Jaroslav Kysela wrote:
> > >
> > > Added ommited clear() functions
> > >
> > > Index: pcm.c
> > >  /**
> > > + * \brief clear snd_pcm_hw_params_t structure
> > > + * \param obj pointer to structure
> > > + */
> > > +void snd_pcm_hw_params_clear(snd_pcm_hw_params_t *obj)
> > > +{
> > > +       assert(obj);
> > > +       memset(obj, 0, snd_pcm_hw_params_sizeof());
> > > +}
> >
> > Why that _clear functions?
> > What's the expected semantic for "clear"?
> >
> > When we designed new API I took in consideration them, but the lack of
> > usefulness and the ambiguity of semantic has pushed me to avoid them.
> 
> Well, you're right that the name is misleading, but wouldn't be good to
> let to reuse a structure? Perhaps, _init suffix is better.

This is fine if we state in documentation that the object will go in the
same state than after OBJ_alloca/OBJ_malloc.

In this case I think that we have to change the memset in the OBJ_alloca
and OBJ_malloc function to OBJ_init call.

That apart there are some OBJs for which the _init function is nonsense.
snd_pcm_hw_params and snd_pcm_sw_params are among that.

The only sensible initializers for snd_pcm_hw_params are the existing
snd_pcm_hw_params_any and snd_pcm_hw_params_current.
Same for snd_pcm_sw_params_current.

To resume: I think that your proposal may have some reason for some OBJ
(but I'm not sure that in this specific ALSA context they exist), but I
think that to have it for OBJs with sane initializer is wrong.

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

Opera Unica                          Phone: +39.546.656023
Via Emilia Interna, 140
48014 Castel Bolognese (RA) - Italy


-------------------------------------------------------
This sf.net email is sponsored by: Influence the future 
of Java(TM) technology. Join the Java Community 
Process(SM) (JCP(SM)) program now. 
http://ads.sourceforge.net/cgi-bin/redirect.pl?sunm0002en