---
title: CustomNSError
framework: foundation
role: symbol
role_heading: Protocol
path: foundation/customnserror
---

# CustomNSError

A specialized error that provides a domain, error code, and user-info dictionary.

## Declaration

```swift
protocol CustomNSError : Error
```

## Topics

### Instance Properties

- [errorCode](foundation/customnserror/errorcode.md)
- [errorUserInfo](foundation/customnserror/erroruserinfo.md)

### Type Properties

- [errorDomain](foundation/customnserror/errordomain.md)

## Relationships

### Inherits From

- [Error](swift/error.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

### Conforming Types

- [CocoaError](foundation/cocoaerror.md)
- [MachError](foundation/macherror.md)
- [POSIXError](foundation/posixerror.md)
- [URLError](foundation/urlerror.md)

## See Also

### User-Relevant Errors

- [Error](swift/error.md)
- [NSError](foundation/nserror.md)
- [LocalizedError](foundation/localizederror.md)
- [RecoverableError](foundation/recoverableerror.md)