source as a “polled” source; when
added to a
child_source will be automatically added
with the same priority, when
child_source is triggered, it will
source to dispatch (in addition to calling its own
callback), and when
source is destroyed, it will destroy
child_source as well. (
source will also still be dispatched if
its own prepare/check functions indicate that it is ready.)
If you don’t need
child_source to do anything on its own when it
triggers, you can call
g_source_set_dummy_callback() on it to set a
callback that does nothing (except return
TRUE if appropriate).
source will hold a reference on
is attached to it.
This API is only intended to be used by implementations of
Do not call this API on a
GSource that you did not create.
Available since: 2.28
The data is owned by the caller of the method.