# Publishers.Breakpoint A publisher that raises a debugger signal when a provided closure needs to stop the process in the debugger. ``` struct Breakpoint where Upstream : Publisher ``` ## Overview When any of the provided closures returns `true`, this publisher raises the `SIGTRAP` signal to stop the process in the debugger. Otherwise, this publisher passes through values and completions as-is. ## Topics ### Creating a breakpoint publisher [`init(upstream:receiveSubscription:receiveOutput:receiveCompletion:)`](/documentation/Combine/Publishers/Breakpoint/init(upstream:receiveSubscription:receiveOutput:receiveCompletion:)) Creates a breakpoint publisher with the provided upstream publisher and breakpoint-raising closures. ### Declaring supporting types [`Publishers.Breakpoint.Output`](/documentation/Combine/Publishers/Breakpoint/Output) The kind of values published by this publisher. [`Publishers.Breakpoint.Failure`](/documentation/Combine/Publishers/Breakpoint/Failure) The kind of errors this publisher might publish. ### Inspecting publisher properties [`upstream`](/documentation/Combine/Publishers/Breakpoint/upstream) The publisher from which this publisher receives elements. [`receiveSubscription`](/documentation/Combine/Publishers/Breakpoint/receiveSubscription) A closure that executes when the publisher receives a subscription, and can raise a debugger signal by returning a true Boolean value. [`receiveOutput`](/documentation/Combine/Publishers/Breakpoint/receiveOutput) A closure that executes when the publisher receives output from the upstream publisher, and can raise a debugger signal by returning a true Boolean value. [`receiveCompletion`](/documentation/Combine/Publishers/Breakpoint/receiveCompletion) A closure that executes when the publisher receives completion, and can raise a debugger signal by returning a true Boolean value. --- 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)