# SystemHandle

> An identifier representing a system instance in a particular world.

## Definition

* **Type:** Struct
* **Namespace:** [Unity.Entities](/engine/7000.0/script-reference/unity/entities.md)
* **Assembly:** UnityEngine.EntitiesModule
* **Implements:** [IEquatable\<SystemHandle>](https://learn.microsoft.com/dotnet/api/system.iequatable-1), [IComparable\<SystemHandle>](https://learn.microsoft.com/dotnet/api/system.icomparable-1)

```csharp
public struct SystemHandle : IEquatable<SystemHandle>, IComparable<SystemHandle>
```

## Static Properties

| Property                                                                    | Description                                                     |
| --------------------------------------------------------------------------- | --------------------------------------------------------------- |
| [Null](/engine/7000.0/script-reference/unity/entities/systemhandle/null.md) | A "blank" SystemHandle that does not refer to an actual system. |

## Methods

| Method                                                                                    | Description                                                                 |
| ----------------------------------------------------------------------------------------- | --------------------------------------------------------------------------- |
| [CompareTo](/engine/7000.0/script-reference/unity/entities/systemhandle/compareto.md)     | Implements IComparable interface for usage in generic sorted containers     |
| [Equals](/engine/7000.0/script-reference/unity/entities/systemhandle/equals.md)           | SystemHandle instances are equal if they refer to the same system instance. |
| [GetHashCode](/engine/7000.0/script-reference/unity/entities/systemhandle/gethashcode.md) | A hash used for comparisons.                                                |
| [Update](/engine/7000.0/script-reference/unity/entities/systemhandle/update.md)           | Update the system manually.                                                 |

## Operators

| Operator                                                                                    | Description                                                                 |
| ------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------- |
| [operator ==](/engine/7000.0/script-reference/unity/entities/systemhandle/op-equality.md)   | SystemHandle instances are equal if they refer to the same system instance. |
| [operator !=](/engine/7000.0/script-reference/unity/entities/systemhandle/op-inequality.md) | SystemHandle instances are equal if they refer to the same system instance. |