Decreases the reference count of
object. When its reference count
drops to 0, the object is finalized (i.e. its memory is freed).
If the pointer to the
GObject may be reused in future (for example, if it is
an instance variable of another object), it is recommended to clear the
NULL rather than retain a dangling pointer to a potentially
GObject instance. Use
g_clear_object() for this.