# scanForNetworks(withSSID:) Scans for networks. ``` func scanForNetworks(withSSID ssid: Data?) throws -> Set ``` ## Parameters `ssid` The SSID for which to scan. ## Return Value A set of CWNetwork objects. ## Discussion If *ssid* parameter is present, a directed scan will be performed by the interface, otherwise a broadcast scan will be performed. This method will block for the duration of the scan. > Handling Errors in Swift: > In Swift, this method returns a nonoptional result and is marked with the `throws` keyword to indicate that it throws an error in cases of failure. > > You call this method in a `try` expression and handle any errors in the `catch` clauses of a `do` statement, as described in [Error Handling](https://docs.swift.org/swift-book/LanguageGuide/ErrorHandling.html) in [The Swift Programming Language](https://docs.swift.org/swift-book/) and `About Imported Cocoa Error Parameters`. --- 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)