Structs

A struct is a data structure that helps you organize and manipulate its member properties. Unreal Engine's reflection system recognizes structs as a UStruct, but they are not part of the UObject ecosystem, and cannot be used inside of UClasses.

• A UStruct is faster to create than a UObject with the same data layout.

• UStruct supports UProperty, but are not managed by the Garbage Collection system and cannot provide the functionality of a UFunction.

Implement a UStruct

To make a struct into a UStruct, follow the steps below:

1. Open the header (.h) file where you want to define your struct.

2. To define your C++ struct, put the USTRUCT macro above the struct's definition.

3. Include the GENERATED_BODY() macro as the first line of the definition.

The result should look like the following example:

	
		USTRUCT([Specifier, Specifier, ...])
		struct FStructName
		{
			GENERATED_BODY()
		};
	
Copy full snippet

USTRUCT([Specifier, Specifier, ...]) struct FStructName { GENERATED_BODY() };

You can tag the struct's member variables with UPROPERTY to make them visible to the Unreal Reflection System and Blueprint Scripting. See the list of UProperty Specifiers to learn how the property can behave in various Modules of the Engine and Editor.

Struct Specifiers

Struct Specifiers provide metadata that controls how your structs behave with various aspects of the Engine and Editor.

Best Practices & Tips

Below are some helpful tips to remember when you use UStruct:

1. UStruct can use Unreal Engine's smart pointer and garbage collection systems to prevent garbage collection from removingUObjects.

2. Structs are best used for simple data types. For more complicated interactions in your project, you might want to make a UObject or AActor subclass instead.

3. UStructs ARE NOT considered for replication. However, UProperty variables ARE considered for replication.

4. Unreal Engine can automatically create Make and Break functions for Structs.

   1. Make appears for any UStruct with the BlueprintType tag.

   2. Break appears if you have at least one BlueprintReadOnly or BlueprintReadWrite property in the UStruct.

   3. The pure node that Break creates provides one output pin for each property tagged as BlueprintReadOnly or BlueprintReadWrite.