Specifies the type of function passed to gst_bus_add_watch() or
gst_bus_add_watch_full(), which is called from the mainloop when a message
is available on the bus.
The message passed to the function will be unreffed after execution of this
function so it should not be freed in the function.
Note that this function is used as a GSourceFunc which means that returning
%FALSE will remove the GSource from the mainloop.
Specifies the type of function passed to gst_bus_add_watch() or gst_bus_add_watch_full(), which is called from the mainloop when a message is available on the bus.
The message passed to the function will be unreffed after execution of this function so it should not be freed in the function.
Note that this function is used as a GSourceFunc which means that returning %FALSE will remove the GSource from the mainloop.