snd_card_load

snd_card_load

[Immanuel Litzroth]

I am currently writing some C++ classes around parts of the alsa
api. I have a lot of work figuring out the semantics of the alsa calls
and am using a combination of the doxygen documentation, the alsalib
source and the sources to programs that use alsa.
The problem I ran into  yesterday concerns the snd_card_load function.
1) the documentation states that that functions returns 0 if the
driver is not present and 1 if it is. The code at the end of the
function goes:

if (open_dev >= 0) {
        close (open_dev);
	return 0;
	}
return open_dev ? 1 : 0;

it seems to me that 0 is returned if the driver is loaded and 1 if it
is not. moreover the last expression (return open_dev ? 1 : 0;) is
superflous and should be just "return 1;"
2) somewhat further in snd_card_get_index the following tests are made
   if(snd_card_load(card) >= 0) --> always true
   if(snd_card_load(card) < 0) --> always false

Am I missing something?
Immanuel

***************************************************************************
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Tubbs Tattsyrup

--
Immanuel Litzroth
Software Development Engineer
Enfocus Software
Antwerpsesteenweg 41-45
9000 Gent
Belgium
Voice: +32 9 269 23 90
Fax : +32 9 269 16 91
Email: Immanuell@enfocus.be
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Re: snd_card_load

[Takashi Iwai]

At 24 Jun 2005 13:28:08 +0200,
Immanuel Litzroth wrote:
> 
> I am currently writing some C++ classes around parts of the alsa
> api. I have a lot of work figuring out the semantics of the alsa calls
> and am using a combination of the doxygen documentation, the alsalib
> source and the sources to programs that use alsa.
> The problem I ran into  yesterday concerns the snd_card_load function.
> 1) the documentation states that that functions returns 0 if the
> driver is not present and 1 if it is. The code at the end of the
> function goes:
> 
> if (open_dev >= 0) {
>         close (open_dev);
> 	return 0;
> 	}
> return open_dev ? 1 : 0;
> 
> it seems to me that 0 is returned if the driver is loaded and 1 if it
> is not. moreover the last expression (return open_dev ? 1 : 0;) is
> superflous and should be just "return 1;"
>
> 2) somewhat further in snd_card_get_index the following tests are made
>    if(snd_card_load(card) >= 0) --> always true
>    if(snd_card_load(card) < 0) --> always false
> 
> Am I missing something?

On both you're right, it's definitely a bug of alsa-lib.
Fixed on CVS.  snd_card_load() follows to the behavior described in
the document now.

Thanks for spotting out this.


Takashi


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