[Pkg-alsa-devel] Bug#564856: Bug#564856: aplay: error message when user not in audio group is unhelpful

[Jonathan Nieder]

Elimar Riesebieter wrote:
> * Jonathan Nieder [100112 04:16 -0600]

>> Trying to play a sound, I get a series of errors
>> 
>> | $ aplay 69550__dataka__mu_eca_piano.wav 
>> | ALSA lib confmisc.c:768:(parse_card) cannot find card '0'
>> | ALSA lib conf.c:4154:(_snd_config_evaluate) function snd_func_card_driver returned error: No such file or directory
>> | ALSA lib confmisc.c:392:(snd_func_concat) error evaluating strings
>> | ALSA lib conf.c:4154:(_snd_config_evaluate) function snd_func_concat returned error: No such file or directory
>> | ALSA lib confmisc.c:1251:(snd_func_refer) error evaluating name
>> | ALSA lib conf.c:4154:(_snd_config_evaluate) function snd_func_refer returned error: No such file or directory
>> | ALSA lib conf.c:4633:(snd_config_expand) Evaluate error: No such file or directory
>> | ALSA lib pcm.c:2211:(snd_pcm_open_noupdate) Unknown PCM default
>> | aplay: main:608: audio open error: No such file or directory
>> 
>> This looks like debugging output.  But the library did not make
>> any mistake: I am not in the audio group, so I do not have access
>> to any sound card, though this was not immediately obvious to me.
>> 
>> Perhaps a more direct message ("cannot find a card to output to"
>> or something) would help.
>
> Well, a message like "Are you member og group audio?" would do the
> job- But there aremany more ways this error can be fixed though.

Just to clarify, I do not care if the output suggests "Are you member
of group audio?"  Of course there are many reasons for ALSA not to
be able to find a card.

But since this is a message primarily for users (the library is not
confused), would it be possible to lose the file names, line numbers,
and traceback?

> Bug won't fix

Is there any way I can help with this?  Examples:

 - If you have specific concerns about the message I suggested
   ("cannot find a card to output to"), I could incrementally improve
   it;

 - With more details about what this condition means, I could probably
   write a more suitable error message;

 - With more time, I would gladly figure out what the condition means
   and how to convince libasound to write such a message, and submit a
   patch.

Or if there is some other way to help get this unhelpful output fixed,
please let me know.

Thanks,
Jonathan