---
title: FSEntityIdentifier
framework: fskit
role: symbol
role_heading: Class
path: fskit/fsentityidentifier
---

# FSEntityIdentifier

A base type that identifies containers and volumes.

## Declaration

```swift
class FSEntityIdentifier
```

## Overview

Overview An FSEntityIdentifier is a UUID to identify a container or volume, optionally with eight bytes of qualifying (differentiating) data. You use the qualifiers in cases in which a file server can receive multiple connections from the same client, which differ by user credentials. In this case, the identifier for each client is the server’s base UUID, and a unique qualifier that differs by client. important: Don’t subclass this class.

## Topics

### Creating an entity identifier

- [init()](fskit/fsentityidentifier/init().md)
- [init(uuid:)](fskit/fsentityidentifier/init(uuid:)-9e20k.md)
- [init(uuid:data:)](fskit/fsentityidentifier/init(uuid:data:)-8dixs.md)
- [init(uuid:qualifier:)](fskit/fsentityidentifier/init(uuid:qualifier:)-9ty70.md)

### Inspecting identifier properties

- [uuid](fskit/fsentityidentifier/uuid.md)
- [qualifier](fskit/fsentityidentifier/qualifier.md)

### Initializers

- [init(UUID:)](fskit/fsentityidentifier/init(uuid:)-1cibs.md)
- [init(UUID:data:)](fskit/fsentityidentifier/init(uuid:data:)-1cpve.md)
- [init(UUID:qualifier:)](fskit/fsentityidentifier/init(uuid:qualifier:)-x26c.md)
- [init(UUID:qualifierData:)](fskit/fsentityidentifier/init(uuid:qualifierdata:)-49874.md)
- [init(coder:)](fskit/fsentityidentifier/init(coder:).md)
- [init(uuid:qualifierData:)](fskit/fsentityidentifier/init(uuid:qualifierdata:)-8xlg1.md)

## Relationships

### Inherits From

- [NSObject](objectivec/nsobject-swift.class.md)

### Inherited By

- [FSContainerIdentifier](fskit/fscontaineridentifier.md)
- [FSVolume.Identifier](fskit/fsvolume/identifier.md)

### Conforms To

- [CVarArg](swift/cvararg.md)
- [Copyable](swift/copyable.md)
- [CustomDebugStringConvertible](swift/customdebugstringconvertible.md)
- [CustomStringConvertible](swift/customstringconvertible.md)
- [Equatable](swift/equatable.md)
- [Escapable](swift/escapable.md)
- [Hashable](swift/hashable.md)
- [Identifiable](swift/identifiable.md)
- [NSCoding](foundation/nscoding.md)
- [NSCopying](foundation/nscopying.md)
- [NSObjectProtocol](objectivec/nsobjectprotocol.md)
- [NSSecureCoding](foundation/nssecurecoding.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)

## See Also

### Supporting types

- [FSBlockmapFlags](fskit/fsblockmapflags.md)
- [FSCompleteIOFlags](fskit/fscompleteioflags.md)
- [FSExtentPacker](fskit/fsextentpacker.md)
- [FSExtentType](fskit/fsextenttype.md)
- [FSMatchResult](fskit/fsmatchresult.md)
- [FSMetadataRange](fskit/fsmetadatarange.md)
- [FSProbeResult](fskit/fsproberesult.md)