# acceptConnectionInBackgroundAndNotify() Accepts a socket connection (for stream-type sockets only) in the background and creates a file handle for the “near” (client) end of the communications channel. ``` func acceptConnectionInBackgroundAndNotify() ``` ## Discussion This method asynchronously creates a file handle for the other end of the socket connection and returns that object by posting a [`NSFileHandleConnectionAccepted`](/documentation/Foundation/NSNotification/Name-swift.struct/NSFileHandleConnectionAccepted) notification in the current thread. The notification includes a `userInfo` dictionary with the created `NSFileHandle` object, which is accessible using the `NSFileHandleNotificationFileHandleItem` key. You must call this method from a thread that has an active run loop. ### Special Considerations The receiver must be created by an [`init(fileDescriptor:)`](/documentation/Foundation/FileHandle/init(fileDescriptor:)) message that takes as an argument a stream-type socket created by the appropriate system routine, *and that is being listened on*. In other words, you must `bind()` the socket, and ensure that the socket has a connection backlog defined by `listen()`. The object that will write data to the returned file handle must add itself as an observer of [`NSFileHandleConnectionAccepted`](/documentation/Foundation/NSNotification/Name-swift.struct/NSFileHandleConnectionAccepted). Note that this method does not continue to listen for connection requests after it posts [`NSFileHandleConnectionAccepted`](/documentation/Foundation/NSNotification/Name-swift.struct/NSFileHandleConnectionAccepted). If you want to keep getting notified, you need to call [`acceptConnectionInBackgroundAndNotify()`](/documentation/Foundation/FileHandle/acceptConnectionInBackgroundAndNotify()) again in your observer method. ## See Also [`- enqueueNotification:postingStyle:coalesceMask:forModes:`](/documentation/Foundation/NotificationQueue/enqueue(_:postingStyle:coalesceMask:forModes:)) Adds a notification to the notification queue with a specified posting style, criteria for coalescing, and run loop mode. --- 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)