Sets a dummy callback for source. The callback will do nothing, and
if the source expects a gboolean return value, it will return TRUE.
(If the source expects any other type of return value, it will return
a 0/NULL value; whatever g_value_init() initializes a GValue to for
that type.)
If the source is not one of the standard GLib types, the
closure_callback and closure_marshal fields of the GSourceFuncs
structure must have been filled in with pointers to appropriate
functions.
Sets a dummy callback for source. The callback will do nothing, and if the source expects a gboolean return value, it will return TRUE. (If the source expects any other type of return value, it will return a 0/NULL value; whatever g_value_init() initializes a GValue to for that type.) If the source is not one of the standard GLib types, the closure_callback and closure_marshal fields of the GSourceFuncs structure must have been filled in with pointers to appropriate functions.