TArray — UE_REQUIRES constraint
#include "Containers/Array.h"
Access: public
Description
Template constraint applied to TArray cross-type constructors and assignment operators. Ensures the source element type is compatible (implicitly constructible or assignable) with the destination element type before the overload participates in overload resolution.
Caveats & Gotchas
- • UE_REQUIRES expands to a C++20 `requires` clause on supported compilers and falls back to a std::enable_if workaround on older toolchains. If your build uses an older compiler standard, error messages for constraint violations may be significantly less readable.
- • The constraint only checks type compatibility, not allocator compatibility. You can copy between TArray<int32, FDefaultAllocator> and TArray<int32, TInlineAllocator<4>>, but the inline buffer will be ignored and heap memory will be used on the destination.
Signature
UE_REQUIRES(UE::Core::Private::TArrayElementsAreCompatible_V<ElementType, const OtherElementType&>)Example
Cross-type array conversion enabled by UE_REQUIRES C++
TArray<int32> IntArray = {1, 2, 3};
// Compiles because int32 is convertible to int64:
TArray<int64> LongArray(IntArray);
// Would NOT compile — UE_REQUIRES rejects the overload:
// TArray<FVector> VecArray(IntArray);See Also
Tags
Version History
Introduced in: 5.1
| Version | Status | Notes |
|---|---|---|
| 5.6 | stable | — |
Feedback
Was this helpful?