# GetSystemTypeIndices(WorldSystemFilterFlags, WorldSystemFilterFlags, WorldSystemFilterFlags)

> Return an array of all System types available to the runtime matching the WorldSystemFilterFlags. By default, all systems available to the runtime is returned. This version avoids unnecessary reflection.

## Definition

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

```csharp
public static NativeList<SystemTypeIndex> GetSystemTypeIndices(WorldSystemFilterFlags filterFlags = WorldSystemFilterFlags.All, WorldSystemFilterFlags requiredFlags = (WorldSystemFilterFlags)0, WorldSystemFilterFlags excludedFlags = WorldSystemFilterFlags.Disabled)
```

### Parameters

**** (\[WorldSystemFilterFlags]\(/engine/7000.0/script-reference/unity/entities/worldsystemfilterflags)): Optional flags - include systems that match any of these flags (OR logic). Defaults to All.**** (\[WorldSystemFilterFlags]\(/engine/7000.0/script-reference/unity/entities/worldsystemfilterflags)): Required flags - include only systems that match all of these flags (AND logic). Defaults to none.**** (\[WorldSystemFilterFlags]\(/engine/7000.0/script-reference/unity/entities/worldsystemfilterflags)): Excluded flags - exclude systems that match any of these flags (NOT logic). Defaults to Disabled, hiding \[DisableAutoCreation] systems.

### Returns

| Type                                                                                             | Description                                                      |
| ------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------- |
| [NativeList\<SystemTypeIndex>](/engine/7000.0/script-reference/unity/collections/nativelist1.md) | Returns a list of systems meeting the flag requirements provided |