From mboxrd@z Thu Jan  1 00:00:00 1970
From: Martin Koegler <martin.koegler@chello.at>
Subject: Re: [PATCH - aconnect 1/1] Fix aconnect printing card
 and pid on older kernels
Date: Fri, 1 Apr 2016 23:28:05 +0200
Message-ID: <20160401212805.GB20661@mail.zuhause>
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To: Adam Goode <agoode@google.com>
Cc: alsa-devel@alsa-project.org, patch@alsa-project.org, martin.koegler@chello.at
List-Id: alsa-devel@alsa-project.org

On Fri, Apr 01, 2016 at 01:35:01PM -0400, Adam Goode wrote:
> alsa-lib is changed to return a distinct negative value if running on
> an older kernel. -1 is only returned now if the kernel knows for sure
> that there is no card or pid. On older kernels, alsa-lib will return
> -ENOSYS.
> 

Shouldn't we also update the default values of card/pid to -ENOSYS to be more consistent:
                int card = -1, pid = -1;

> @@ -177,13 +177,13 @@ static void print_port(snd_seq_t *seq, snd_seq_client_info_t *cinfo,
>  #ifdef HAVE_SEQ_CLIENT_INFO_GET_CARD
>  		card = snd_seq_client_info_get_card(cinfo);
>  #endif
> -		if (card != -1)
> +		if (card >= 0)
>  			printf(",card=%d", card);

aconnect from alsa-utils 1.1.1 will break with alsa-lib containing your patch.

The new API is propably not yet widely used, so I think that a ABI change can still be possible.
But in that case, alsa-lib/alsa-utils 1.1.1 need quickly be replaced by new releases, so that people
don't start using the old API.

Regards,
Martin