---
title: ComputeNodeGraph.StructureDefinition
framework: Compute Graph
role: symbol
role_heading: Structure
platforms: [iOS 27.0+, iPadOS 27.0+, Mac Catalyst 27.0+, macOS 27.0+, tvOS 27.0+, visionOS 27.0+]
path: computegraph/computenodegraph/structuredefinition
---

# ComputeNodeGraph.StructureDefinition

A named structure type, pairing a type name with its in-memory layout.

## Declaration

```swift
struct StructureDefinition
```

## Overview

Overview A structure definition describes a composite value that can flow through a compute graph. It associates a Swift- or Metal-visible type name with a ComputeNodeGraph.StructureLayout that lays out the structure’s members, their offsets, and its overall size and stride. Use a structure definition to refer to user-defined aggregate types from other graph types, such as ComputeNodeGraph.ValueType.structure(definition:) or ComputeNodeGraph/StateType/structure(typeName:layout:).

## Topics

### Initializers

- [init(typeName:layout:)](computegraph/computenodegraph/structuredefinition/init(typename:layout:).md)

### Instance Properties

- [layout](computegraph/computenodegraph/structuredefinition/layout.md)
- [typeName](computegraph/computenodegraph/structuredefinition/typename.md)

## Relationships

### Conforms To

- [Equatable](swift/equatable.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)