[pulseaudio-discuss] Receiving signals from server in C
gregknoll at gmail.com
Fri Jun 13 08:17:16 PDT 2014
I think first it would be good to know that I'm correctly registering
with ListenForSignal. First I use
conn = dbus_connection_open(serverAddress, &err);
to get a connection to PulseAudio. Then I call the message:
msg = dbus_message_new_method_call(
"/org/pulseaudio/core1", //Object path to call on
"org.PulseAudio.Core1", //Interface to call on
//Add arguments: s, 
//empty array to listen to all
//call dbus function
debug_print(" >...Listening for signal %s...\n",signalName);
dbus_connection_send_with_reply_and_block (conn, msg, -1, &err);
with signalName = "org.PulseAudio.Core1.NewModule"
Is this correct if I want to be notified when all new modules are loaded?
If so, I then call dbus_connection_pop_message on the private
connection in the main loop.
Do I need to add a match?
On Wed, Jun 4, 2014 at 11:06 AM, Tanu Kaskinen
<tanu.kaskinen at linux.intel.com> wrote:
> On Mon, 2014-06-02 at 13:48 +0200, Greg Knoll wrote:
>> On Fri, May 30, 2014 at 3:44 PM, Tanu Kaskinen
>> <tanu.kaskinen at linux.intel.com> wrote:
>> > (Added pulseaudio-discuss back to cc.)
>> > On Fri, 2014-05-30 at 15:24 +0200, Greg Knoll wrote:
>> >> Thank you for your response,
>> >> Yes, I did follow that tutorial. I didn't state it correctly in my
>> >> question, but I do only use the session bus to get the server
>> >> address. Then I use
>> >> *conn = dbus_connection_open(serverAddress, &err);
>> >> to get the DBusConnection object and use this to make calls.
>> > Ok, I suppose this is not the problem then. Back to the original
>> > question:
>> >> However, where/how do I listen for the signal? I also tried setting a
>> >> dbus match rule:
>> >> dbus_bus_add_match(system_bus, "type='signal',interface='org.PulseAudio.Core1'", &err);
>> > You don't need to add a match rule (trying to do so won't do anything
>> > useful, because the match rules are managed by the bus daemon, and in a
>> > peer-to-peer connection there's no bus daemon involved at all). Do you
>> > register a message filter with dbus_connection_add_filter()? If not,
>> > then that's the problem.
>> > By the way, please don't top-post on mailing lists, and also plain text
>> > messages are preferred over HTML.
>> > --
>> > Tanu
>> Sorry about the top post.
>> I did not register a dbus_connection_add_filter(). I have added a
>> DBusHandlerResult function based on the examples here:
>> The second one uses an object DBusMessageHandler, which I think is
>> from glib/dbus-glib. Maybe I'm wrong there. My function looks like
>> DBusHandlerResult listen_to_core_Handler(DBusConnection *connection,
>> DBusMessage *message, void *user_data)
>> debug_print("Message received from Pulse Core.\n");
>> debug_print("Signature:%s\n", dbus_message_get_signature(message));
>> and I add a call to dbus_connection_add_filter() in my main thread using:
>> dbus_connection_add_filter(PA_bus, listen_to_core_Handler, NULL, NULL);
>> Still nothing. I should also say that the signal name string I'm
>> using is "org.PulseAudio.Core1.NewModule".
>> Thanks for all the help so far.
> How do you dispatch incoming messages? Do you integrate the D-Bus
> connection with some event loop, or do you manually call
> dbus_connection_read_write_dispatch() in a loop or something similar?
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