# CFNetServiceResolveWithTimeout(_:_:_:) Gets the IP address or addresses for a CFNetService. ``` func CFNetServiceResolveWithTimeout(_ theService: CFNetService, _ timeout: CFTimeInterval, _ error: UnsafeMutablePointer?) -> Bool ``` ## Parameters `theService` The CFNetService to resolve; cannot be `NULL`. The resolution will fail if the service doesn’t have a domain, a type, and a name. `timeout` Value of type `CFTimeInterval` specifying the maximum amount of time allowed to perform the resolution. If the resolution is not performed within the specified amount of time, a timeout error will be returned. If `timeout` is less than or equal to zero, an infinite amount of time is allowed. `error` Pointer to a structure that will be set to an error code and the error code’s domain if an error occurs; or `NULL` if you don’t want to receive the error code and its domain. ## Return Value `TRUE` if an asynchronous service resolution was started or if a synchronous service resolution updated the CFNetService; `FALSE` if an asynchronous or synchronous resolution failed or timed out, or if a synchronous resolution was canceled. ## Discussion This function updates the specified CFNetService with the IP address or addresses associated with the service. Call [`CFNetServiceGetAddressing(_:)`](/documentation/CFNetwork/CFNetServiceGetAddressing(_:)) to get the addresses. When resolving a service that runs in asynchronous mode, this function returns `TRUE` if the CFNetService has a domain, type, and name, and the underlying resolution process was started. Otherwise, this function returns `FALSE`. Once started, the resolution continues until it is canceled by calling [`CFNetServiceCancel(_:)`](/documentation/CFNetwork/CFNetServiceCancel(_:)). When resolving a service that runs in synchronous mode, this function blocks until the CFNetService is updated with at least one IP address, until an error occurs, or until [`CFNetServiceCancel(_:)`](/documentation/CFNetwork/CFNetServiceCancel(_:)) is called. ### Special Considerations This function is thread safe. If the service will be used in asynchronous mode, you must call [`CFNetServiceSetClient(_:_:_:)`](/documentation/CFNetwork/CFNetServiceSetClient(_:_:_:)) before calling this function. --- 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)