GObjectWeakRef

A structure containing a weak reference to a GObject.

A GWeakRef can either be empty (i.e. point to NULL), or point to an object for as long as at least one “strong” reference to that object exists. Before the object’s GObjectClass.dispose method is called, every GWeakRef associated with becomes empty (i.e. points to NULL).

Like GValue, GWeakRef can be statically allocated, stack- or heap-allocated, or embedded in larger structures.

Unlike g_object_weak_ref() and g_object_add_weak_pointer(), this weak reference is thread-safe: converting a weak pointer to a reference is atomic with respect to invalidation of weak pointers to destroyed objects.

GWeakRefs are reset before calling GObjectClass.dispose. If the object’s GObjectClass.dispose method results in additional references to the object being held (‘re-referencing’), any GWeakRefs taken before it was disposed will continue to point to NULL. If during disposal the object gets re-referenced and resurrected, the GWeakRefs taken during disposal will be set until the reference count drops towards zero again and GObjectClass.dispose is called again. If GWeakRefs were taken during disposal but the object not resurrected, they will be set to NULL right after, before finalization.

Note that GObjectClass.run_dispose() also resets GWeakRefs. As such, the GWeakRef actually tracks whether GObjectClass.dispose() was called and not the reference count reaching zero.