# makeWriteSource(fileDescriptor:queue:) Creates a new dispatch source object for writing data to the specified file. ``` class func makeWriteSource(fileDescriptor: Int32, queue: DispatchQueue? = nil) -> any DispatchSourceWrite ``` ## Parameters `fileDescriptor` A file descriptor pointing to an open file or socket. The dispatch source begins writing at the file descriptor’s current location. `queue` The dispatch queue to use when executing the installed handlers. ## Return Value A dispatch source object that conforms to the [`DispatchSourceWrite`](/documentation/Dispatch/DispatchSourceWrite) protocol. ## Discussion After creating the dispatch source, use the methods of the [`DispatchSourceProtocol`](/documentation/Dispatch/DispatchSourceProtocol) protocol to install the event handlers you need. The returned dispatch source is in the inactive state initially. When you are ready to begin processing events, call its [`activate()`](/documentation/Dispatch/DispatchObject/activate()) method. --- 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)