[alsa-devel] snd_ctl_elem_list

Paul paul at redpineinstruments.org
Mon Oct 15 07:09:40 CEST 2012

Newbie. Trying to discover information about the audio hardware. 
Specifically about a USB microphone ( Audio-Technia AT2020USB ) and 
whether it has a volume control. Writing in Ada just to be difficult. 
Not having any problems with that though.

After doing a malloc and a snd_ctl_elem_list I can use 
ctl_elem_list_count to get the number of elements. This number is 
non-zero ( 2 for the AT2020, 34 for the on-board Intel audio chip  ).

Then I can use ctl_elem_to get the number of used. That number is zero 
and prevents me from trying to access the element list.

How can I find out information about the elements in the list? How do 
these elements become used? Is this even the correct path to try to 
discover the volume control?


Paul I

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