On 2014-09-18 02:18, Glenn Golden wrote:
David Henningsson <[email protected]> [2014-09-17 10:47:09 +0200]:
On 2014-09-17 02:38, Glenn Golden wrote:
David Henningsson <[email protected]> [2014-09-16 08:02:50 +0200]:
In 5b-c, is it possible that XDG_RUNTIME_DIR was intended?
Yes, I meant XDG_RUNTIME_DIR. Sorry for the typo.
No problem, just wanted to be sure, thanks for clarifying.
But just to prove that no good deed goes unpunished, :) I'll pester you with
yet another question:
Can you describe what pieces of information the pa_context_connect() API
function takes into account in determining (or guessing at) the server?
The motivation for this question is that I'm wondering if this function is
the means by which a commandline option like "--server=XXXX" is handled
(e.g., by the caller providing "XXXX" to the function as a potential
candidate server, to be decided upon in addition to other pieces of info...) ?
If you give a "--server" argument to pactl, pactl passes that argument
unchanged when it calls pa_context_connect(), hence the command line
argument falls under point 1) in my list, for pactl.
Other applications might do things differently, e g by having a dialog box
where you can configure the server name, and some are probably always
passing NULL out of simplicity or laziness. Does that answer your question?
It answers the original one, thanks. Unfortunately (for you :) ) it brings up
yet another one (or actually, two related questions).
When all this is done, you'll write up a nice wiki page or blog post
explaining it all, right? :-)
Background: Here's the first portion of the list you supplied earlier after
looking thru the code (which, btw, I greatly appreciate, thanks):
1) Specified server(s) in the call to the pa_context_connect().
2) Specified server(s) in PULSE_SERVER
3) Specified server(s) in X11 property PULSE_SERVER
4) Specified server(s) as in client.conf (the "default-server" key)
First question: If the caller does supply NULL as the 'server' parm to
pa_context_connect(),
...then that means, move on to step 2) in the list above.
the doc for that function indicates that it will attempt
to connect to the default server. But if so, then it effectively short-circuits
the above sequence, first trying default-server, then PULSE_SERVER envar,
then PULSE_SERVER X11 prop. Is that right?
Second question (partly related to above): I want to make sure I understand
how the difference between the following two situations is handled:
* A given server specification (e.g. PULSE_SERVER) is not set.
* A given server specification is set, but attempting to connect to that
server leads to a connect error.
There are two lists here, let us not confuse them. We have the 1-9 list
which I provided, and we have the server_list.
The server_list is a list of servers to try in order, so that if one
fails, try the next one.
For step 1) to 4) in my 1-9 list, anything non-NULL will completely make
up the entire server_list. You can even specify more than one server,
just separate your servers with newlines, tabs or spaces and it will be
two or more items in the server_list.
If all of 1) to 4) are NULL/unset, for step 5) to 9) in my 1-9 list, the
server_list is additive. I e, all of step 5) to 9) will result in one or
zero more items added to the server_list.
And when the server_list has been populated, all servers in the
server_list will be tried, in order, until one succeeds.
E g, if you have a command line looking like this:
PULSE_SERVER="hostA hostB" pactl --server="hostC hostD"
...we will try hostC first, and if that fails, try hostD. hostA and
hostB will not be tried, because step 1) is non-NULL.
--
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic
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