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# FunctionType(IType,IType\[])

Constructor in [FunctionType](/3.1/api/csharp/yarn/yarn.functiontype.md)

## Summary

Initialises a new instances of the [FunctionType](/3.1/api/csharp/yarn/yarn.functiontype.md) class.

```csharp
public FunctionType(IType returnType, params IType[] parameterTypes)
```

## Parameters

| Name                                                                | Description                                                     |
| ------------------------------------------------------------------- | --------------------------------------------------------------- |
| [Yarn.IType](/3.1/api/csharp/yarn/yarn.itype.md) returnType         | The type of the value that this type of function returns.       |
| [Yarn.IType\[\]](/3.1/api/csharp/yarn/yarn.itype.md) parameterTypes | The types of the parameters that this type of function accepts. |