Copyright | Will Thompson and Iñaki García Etxebarria |
---|---|
License | LGPL-2.1 |
Maintainer | Iñaki García Etxebarria |
Safe Haskell | Safe-Inferred |
Language | Haskell2010 |
A structure containing a weak reference to a Object
.
A GWeakRef
can either be empty (i.e. point to Nothing
), or point to an
object for as long as at least one "strong" reference to that object
exists. Before the object's ObjectClass
.dispose
method is called,
every WeakRef
associated with becomes empty (i.e. points to Nothing
).
Like Value
, WeakRef
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.
If the object's ObjectClass
.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 Nothing
. Any GWeakRefs
taken
during disposal and after re-referencing, or after disposal has returned due
to the re-referencing, will continue to point to the object until its refcount
goes back to zero, at which point they too will be invalidated.
It is invalid to take a WeakRef
on an object during ObjectClass
.dispose
without first having or creating a strong reference to the object.
Exported types
Memory-managed wrapper type.
Instances
Eq WeakRef Source # | |
BoxedPtr WeakRef Source # | |
Defined in GI.GObject.Structs.WeakRef boxedPtrCopy :: WeakRef -> IO WeakRef boxedPtrFree :: WeakRef -> IO () | |
ManagedPtrNewtype WeakRef Source # | |
Defined in GI.GObject.Structs.WeakRef toManagedPtr :: WeakRef -> ManagedPtr WeakRef |