# application(_:openTempFile:) Returns a Boolean value that indicates if the app opens the specified temporary file. ``` @MainActor optional func application(_ sender: NSApplication, openTempFile filename: String) -> Bool ``` ## Parameters `sender` The application object associated with the delegate. `filename` The name of the temporary file to open. ## Return Value if the file was successfully opened or if it was not. ## Discussion Sent directly by `theApplication` to the delegate. The method should attempt to open the file `filename`, returning if the file is successfully opened, and otherwise. By design, a file opened through this method is assumed to be temporary—it’s the application’s responsibility to remove the file at the appropriate time. --- 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)