TWeakPtr

struct Core Since 4.0

#include "Templates/SharedPointer.h"

Description

A non-intrusive weak reference to an object managed by TSharedPtr/TSharedRef. Does not contribute to the reference count and becomes invalid when all strong references are gone.

Caveats & Gotchas

• TWeakPtr is for non-UObject types only. For UObject weak references use TWeakObjectPtr.
• To use the pointer, call Pin() to get a TSharedPtr — this atomically checks validity and creates a strong reference.
• Not thread-safe by default. Use ESPMode::ThreadSafe if shared across threads.

Signature

template<class ObjectType, ESPMode InMode> class TWeakPtr

Example

Observer pattern with TWeakPtr C++

TWeakPtr<FMySystem> WeakSystem;

TSharedPtr<FMySystem> System = MakeShared<FMySystem>();
WeakSystem = System;

// Later, after System may have been released:
if (TSharedPtr<FMySystem> Pinned = WeakSystem.Pin())
{
    Pinned->DoWork();
}

Functions (4)

Utility 4

Utility

4 ▼

Access	Type	Name	Description
public	function	TWeakPtr::Reset	Removes this weak pointer's reference to the object by default-constructing a new empty TWeakPtr over itself.
public	function	TWeakPtr::GetWeakPtrTypeHash	Returns a hash of the weak pointer based on the raw object address, suitable for use in TSet and TMap containers.
public	function	TWeakPtr::UE_REQUIRES (constrained conversion constructor)	Constrained conversion constructor that copies a TWeakPtr<OtherType> into a TWeakPtr<ObjectType> only when OtherType* is convertible to ObjectType*.
public	function	TWeakPtr::UEOpEquals	Equality comparison for TWeakPtr that pins both sides to shared pointers and compares the resulting raw pointers.

Properties

Access	Type	Name	Description
private	property	TWeakPtr::Object	Raw pointer to the referenced object.
private	property	TWeakPtr::WeakReferenceCount	The weak reference controller shared among all TSharedPtr and TWeakPtr instances pointing to the same object.

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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