TSharedRef::UE_REQUIRES
#include "Templates/SharedPointer.h"
Access: public
Specifiers: inlineexplicit
Description
Template constraint on TSharedRef's converting constructors that ensures only type-compatible (upcast-safe) pointer types can implicitly construct a TSharedRef<ObjectType>.
Caveats & Gotchas
- • Unlike TSharedPtr, TSharedRef has no default constructor. Every constructor must receive a non-null pointer, and the UE_REQUIRES constraint additionally enforces type safety. Passing a pointer that fails the constraint produces a hard compile error.
- • The constraint does not apply to the private constructors used by StaticCastSharedRef and ConstCastSharedRef, which use explicit cast tags to bypass it.
- • TSharedRef enforces non-null at runtime via a check(InObject != nullptr) call inside Init(), in addition to the compile-time type constraint. Both checks must pass.
Signature
UE_REQUIRES(std::is_convertible_v<OtherType*, ObjectType*>)Parameters
| Name | Type | Description | Default |
|---|---|---|---|
| OtherType | template parameter | Source pointer type. Must be implicitly convertible to ObjectType* for the constructor to be considered. | — |
Example
Upcast is implicit; downcast requires StaticCastSharedRef C++
TSharedRef<FDerived> DerivedRef = MakeShared<FDerived>();
// OK: FDerived* is convertible to FBase*
TSharedRef<FBase> BaseRef = DerivedRef;
// ERROR — violates UE_REQUIRES:
// TSharedRef<FDerived> BackRef = BaseRef;
// Correct downcast:
TSharedRef<FDerived> BackRef = StaticCastSharedRef<FDerived>(BaseRef);See Also
Tags
Version History
Introduced in: 5.0
| Version | Status | Notes |
|---|---|---|
| 5.6 | stable | — |
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