> For the complete documentation index, see [llms.txt](https://docs.yarnspinner.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.yarnspinner.dev/3.1/api/csharp/yarn.unity/yarn.unity.actions/yarn.unity.actions.registerfunctiondeclaration.md).

# RegisterFunctionDeclaration(string,Type,Type\[])

Method in [Actions](/3.1/api/csharp/yarn.unity/yarn.unity.actions.md)

## Summary

```csharp
public void RegisterFunctionDeclaration(string name, Type returnType, Type[] parameterTypes)
```

## Parameters

| Name                    | Description |
| ----------------------- | ----------- |
| `string` name           |             |
| `Type` returnType       |             |
| `Type[]` parameterTypes |             |