# Publishers.Share A publisher that shares the output of an upstream publisher with multiple subscribers. ``` final class Share where Upstream : Publisher ``` ## Overview This publisher type supports multiple subscribers, all of whom receive unchanged elements and completion states from the upstream publisher. > Tip: ``doc://com.apple.Combine/documentation/Combine/Publishers/Share`` is effectively a combination of the ``doc://com.apple.Combine/documentation/Combine/Publishers/Multicast`` and ``doc://com.apple.Combine/documentation/Combine/PassthroughSubject`` publishers, with an implicit ``doc://com.apple.Combine/documentation/Combine/ConnectablePublisher/autoconnect()``. Be aware that [`Publishers.Share`](/documentation/Combine/Publishers/Share) is a class rather than a structure like most other publishers. Use this type when you need a publisher instance that uses reference semantics. ## Topics ### Creating a share publisher [`init(upstream:)`](/documentation/Combine/Publishers/Share/init(upstream:)) Creates a publisher that shares the output of an upstream publisher with multiple subscribers. ### Declaring supporting types [`Publishers.Share.Output`](/documentation/Combine/Publishers/Share/Output) The kind of values published by this publisher. [`Publishers.Share.Failure`](/documentation/Combine/Publishers/Share/Failure) The kind of errors this publisher might publish. ### Inspecting publisher properties [`upstream`](/documentation/Combine/Publishers/Share/upstream) The publisher from which this publisher receives elements. ### Comparing publishers [`==(_:_:)`](/documentation/Combine/Publishers/Share/==(_:_:)) Returns a Boolean value that indicates whether two publishers are equivalent. --- 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)