---
title: "objc_registerProtocol(_:)"
framework: Objective-C Runtime
role: symbol
role_heading: Function
platforms: [iOS 4.3+, iPadOS 4.3+, Mac Catalyst 13.1+, macOS 10.7+, tvOS 9.0+, visionOS 1.0+, watchOS 1.0+]
path: "objectivec/objc_registerprotocol(_:)"
---

# objc_registerProtocol(_:)

Registers a newly created protocol with the Objective-C runtime.

## Declaration

```swift
func objc_registerProtocol(_ proto: Protocol)
```

## Parameters

- `proto`: The protocol you want to register with the Objective-C runtime.

## Discussion

Discussion When you create a new protocol using the objc_allocateProtocol(_:), you then register it with the Objective-C runtime by calling this function. After a protocol is successfully registered, it is immutable and ready to use.

## See Also

### Working with Protocols

- [objc_getProtocol(_:)](objectivec/objc_getprotocol(_:).md)
- [objc_copyProtocolList(_:)](objectivec/objc_copyprotocollist(_:).md)
- [objc_allocateProtocol(_:)](objectivec/objc_allocateprotocol(_:).md)
- [protocol_addMethodDescription(_:_:_:_:_:)](objectivec/protocol_addmethoddescription(_:_:_:_:_:).md)
- [protocol_addProtocol(_:_:)](objectivec/protocol_addprotocol(_:_:).md)
- [protocol_addProperty(_:_:_:_:_:_:)](objectivec/protocol_addproperty(_:_:_:_:_:_:).md)
- [protocol_getName(_:)](objectivec/protocol_getname(_:).md)
- [protocol_isEqual(_:_:)](objectivec/protocol_isequal(_:_:).md)
- [protocol_copyMethodDescriptionList(_:_:_:_:)](objectivec/protocol_copymethoddescriptionlist(_:_:_:_:).md)
- [protocol_getMethodDescription(_:_:_:_:)](objectivec/protocol_getmethoddescription(_:_:_:_:).md)
- [protocol_copyPropertyList(_:_:)](objectivec/protocol_copypropertylist(_:_:).md)
- [protocol_getProperty(_:_:_:_:)](objectivec/protocol_getproperty(_:_:_:_:).md)
- [protocol_copyProtocolList(_:_:)](objectivec/protocol_copyprotocollist(_:_:).md)
- [protocol_conformsToProtocol(_:_:)](objectivec/protocol_conformstoprotocol(_:_:).md)