# CFNetServiceCreate(_:_:_:_:_:) Creates an instance of a Network Service object. ``` func CFNetServiceCreate(_ alloc: CFAllocator?, _ domain: CFString, _ serviceType: CFString, _ name: CFString, _ port: Int32) -> Unmanaged ``` ## Parameters `alloc` The allocator to use to allocate memory for the new object. Pass `NULL` or to use the current default allocator. `domain` The domain in which the CFNetService is to be registered; cannot be `NULL`. Call [`CFNetServiceBrowserCreate(_:_:_:)`](/documentation/CFNetwork/CFNetServiceBrowserCreate(_:_:_:)) and [`CFNetServiceBrowserSearchForDomains(_:_:_:)`](/documentation/CFNetwork/CFNetServiceBrowserSearchForDomains(_:_:_:)) to get the registration domain. `name` A unique name if the instance will be used to register a service. The name will become part of the instance name in the DNS records that will be created when the service is registered. If the instance will be used to resolve a service, the name should be the name of the machine or service that will be resolved. `port` Local IP port, in host byte order, on which this service accepts connections. Pass zero to get placeholder service. With a placeholder service, the service will not be discovered by browsing, but a name conflict will occur if another client tries to register the same name. Most applications do not need to use placeholder service. ## Return Value A new net service object, or `NULL` if the instance could not be created. Ownership follows the [The Create Rule](https://developer.apple.com/library/archive/documentation/CoreFoundation/Conceptual/CFMemoryMgmt/Concepts/Ownership.html#//apple_ref/doc/uid/20001148-103029). ## Discussion If the service depends on information in DNS TXT records, call `CFNetServiceSetProtocolSpecificInformation`. If the CFNetService is to run in asynchronous mode, call [`CFNetServiceSetClient(_:_:_:)`](/documentation/CFNetwork/CFNetServiceSetClient(_:_:_:)) to prepare the service for running in asynchronous mode. Then call [`CFNetServiceScheduleWithRunLoop(_:_:_:)`](/documentation/CFNetwork/CFNetServiceScheduleWithRunLoop(_:_:_:)) to schedule the service on a run loop. Then call [`CFNetServiceRegister`](/documentation/CFNetwork/CFNetServiceRegister) to make the service available. If the CFNetService is to run in synchronous mode, call [`CFNetServiceRegister`](/documentation/CFNetwork/CFNetServiceRegister). To terminate a service that is running in asynchronous mode, call [`CFNetServiceCancel(_:)`](/documentation/CFNetwork/CFNetServiceCancel(_:)) and [`CFNetServiceUnscheduleFromRunLoop(_:_:_:)`](/documentation/CFNetwork/CFNetServiceUnscheduleFromRunLoop(_:_:_:)). To terminate a service that is running in synchronous mode, call [`CFNetServiceCancel(_:)`](/documentation/CFNetwork/CFNetServiceCancel(_:)). ### Special Considerations This function is thread safe. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)