For some USTRUCT structs within UnrealEngine, type traits TStructOpsTypeTraits<T> are defined. These provide a list of bools (encapsulated in an enumeration) about the implemented capabilities of struct T.
- What is the usage of those traits?
- When I should define those traits for my custom
USTRUCTs within my project?
*Example usage from within the Engine:
struct TStructOpsTypeTraitsBase2
{
enum
{
WithZeroConstructor = false, // struct can be constructed as a valid object by filling its memory footprint with zeroes.
WithNoInitConstructor = false, // struct has a constructor which takes an EForceInit parameter which will force the constructor to perform initialization, where the default constructor performs 'uninitialization'.
WithNoDestructor = false, // struct will not have its destructor called when it is destroyed.
WithCopy = !TIsPODType<CPPSTRUCT>::Value, // struct can be copied via its copy assignment operator.
// ...
}
}
Which is used like
template<>
struct TStructOpsTypeTraits<FGameplayEffectContextHandle> : public TStructOpsTypeTraitsBase2<FGameplayEffectContextHandle>
{
enum
{
WithCopy = true, // Necessary so that TSharedPtr<FGameplayEffectContext> Data is copied around
WithNetSerializer = true,
WithIdenticalViaEquality = true,
};
};