[alsa-devel] Detecting new alsa sequencer clients (with some event loop) so that i can subscribe them

R. Dresens chromisx at nedlinux.nl
Tue Apr 1 03:48:01 CEST 2008


I'm currently writing an application that will be able to 'auto
subscribe' itself to a certain sequencer client when that client
becomes available to the system. I want (for example) to be able to 
plug in a USB MIDI interface, and when I do that then my application
detects this and does a subscription on it, just like aconnect would

A possible solution is polling; every second or so, i could generate a
list of clients with snd_seq_query_next_client and look for a certain
client name (libpcre comes to mind here;), but I was wondering if there
is a better solution? ..in other words, is it possible to get such
events from the system in a similar way like one would receive regular
MIDI events?

list all the events; an interesting one could be snd_seq_connect_t
for monitoring connections on my own ports, but that's not what I'm
looking for. I can't seem to find an event related to this
functionality. Is there something what I'm currently overlooking?

Such functionality may be usefull for GUI versions of aconnect. I
looked in the source of qjackctl (it has an alsa patchbay), but I
haven't found nothing usefull yet since it seems to me that this
software also does polling/refresh on a certain interval.

Has anyone a usefull tip for me?

Thanks in advance,


Raymond Dresens.

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