public uint add_watch (int priority, owned BusFunc func)
Adds a bus watch to the default main context with the given
It is also possible to use a non-default main context set up using push_thread_default (before one had to create a bus watch source and attach it to the desired main context 'manually').
This function is used to receive asynchronous messages in the main loop. There can only be a single bus watch per bus, you must remove it before you can set a new one.
The bus watch will only work if a MainLoop is being run.
func is called, the message belongs to the caller; if you want to keep a copy of it, call
The bus watch will take its own reference to the this, so it is safe to unref this using unref after setting the bus watch.
a Bus to create the watch for.
The priority of the watch.
A function to call when a message is received.
the function to call when the source is removed.
user data passed to
The event source id or 0 if this already got an event source.