# OnUpdate(ref SystemState)

> Executes world update allocator reset system to rewind memories of the world update allocator.

## Definition

* **Type:** Method
* **Namespace:** [Unity.Entities](/engine/7000.0/script-reference/unity/entities.md)
* **Assembly:** UnityEngine.EntitiesModule

## OnUpdate(SystemState)

```csharp
public void OnUpdate(ref SystemState state)
```

### Parameters

**** (\[SystemState]\(/engine/7000.0/script-reference/unity/entities/systemstate)): The SystemState of the system.