--- title: "UML Statechart tip: Handling errors when entering a state" url: https://daily.dev/posts/uml-statechart-tip-handling-errors-when-entering-a-state-ibgmlap8a source_url: https://www.embeddedrelated.com/showarticle/1334.php type: article source: "EmbeddedRelated" published: 2026-05-31T07:47:55.569Z updated: 2026-05-31T09:12:22.082Z tags: ["architecture", "embedded", "firmware"] reading_time: 8 upvotes: 0 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # UML Statechart tip: Handling errors when entering a state **[EmbeddedRelated](https://daily.dev/sources/embeddedrelated)** · 8 min read · 0 upvotes · 0 comments ## Summary Handling synchronous errors during state entry in UML statecharts is non-trivial because the UML spec forbids transitions inside entry actions. Three practical firmware patterns are compared: (1) Explicit guarded transitions — simple and UML-compliant but can violate DRY in larger codebases; (2) Failure-event self-posting via a LIFO queue — keeps logic contained in one state but requires framework support and breaks with multiple error conditions; (3) Asynchronous service — converts the synchronous operation into an async one with explicit success/failure events, preferred for larger teams and complex projects despite added complexity. Each approach is evaluated with concrete trade-offs and guidance on when to apply it based on project size and team scale. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Welcome to the State Machine Pattern](https://daily.dev/posts/welcome-to-the-state-machine-pattern-5itzjs3mx) · W endell Adriel · 84 upvotes · 1 comments - [Do you need to build a State Machine at least once in your career?](https://daily.dev/posts/do-you-need-to-build-a-state-machine-at-least-once-in-your-career--e8ny0dmmn) · RUBYLAND · 0 upvotes · 0 comments --- Tags: [#architecture](https://daily.dev/tags/architecture), [#embedded](https://daily.dev/tags/embedded), [#firmware](https://daily.dev/tags/firmware) [View this post on daily.dev](https://daily.dev/posts/uml-statechart-tip-handling-errors-when-entering-a-state-ibgmlap8a)