LCP beyond LADSPA? was Re: [linux-audio-dev] PTAF link and comments

[Paul Davis]

>Quick (?) LCP question:
>how closely is it tied to LADSPA?

not really tied to LADSPA at all.

>Does it only support LADSPA float ports? (I guess it would.)

yes.

>I downloaded the tarball, but there's no docs and few comments
>so I can only guess how it's intended to work... looks like
>there's a central LCP server that clients interact with?

not really a central LCP server. a given LADSPA host app becomes an
LCP server. it has to fork/exec the clients, telling them (1) who it
is and (2) the ID of the plugin, which they will include in messages
back to the host.
 
>I'm wondering if LCP would be at all useful for this. I'd have to write
>an LCP "driver" for Sfront. Fortunately, sfront makes it pretty easy
>to write new Audio and Control "drivers".  Witness the fact that
>even a dummy-level C programmer like myself can write a mostly-working
>JACK "driver".

its pretty simple. have a look at the examples in c.c and s.c (client
and server, respectively). you just arrange to call the relevant LCP
client handler whenever there appears to be I/O on the relevant file
descriptor, and call the write function to send new values to the plugin.

--p