# Headless Check This function block reports whether the current run is operating in headless mode (no user interface). Use it to adapt behavior when running on servers or automated environments. ## đŸ“Ĩ Inputs This block does not have any inputs. ## 📤 Outputs `Check` This output provides a boolean value: TRUE when the scenario is running headless, FALSE when a user interface is available. ## 🕹ī¸ Controls This block does not expose any user controls. ## đŸŽ¯ Features * Simple TRUE/FALSE indicator suitable for flow control. * Lightweight and safe to place anywhere in the flow to adapt downstream behavior. * Works well as a gating signal for UI-dependent blocks or for toggling logging and export behavior in automated runs. ## 📝 How to use 1. Place the block where you need to decide between UI and non-UI behavior. 2. Connect the `Check` output to logic or control blocks to enable/disable branches (for example, to skip visual outputs when headless). 3. Use the result with logic blocks (And / Or / Not) or flow-control blocks to implement conditional behavior. ## 📊 Evaluation When evaluated, this block returns a single boolean on `Check` indicating the presence or absence of a user interface for the current run. ## 💡 Tips and Tricks * To avoid opening windows on servers, use `Check` to gate `Show Image` so image viewers are only enabled when not headless. * In headless runs you may prefer saving results instead of showing them. Combine `Check` with export blocks like Image Logger, Image Write, Record Video, or CSV Export to automatically save outputs when headless. * Use `Check` together with logic blocks such as Not, And or Or to build flexible rules (for example: save images only when headless AND a `Logic Input` trigger is active). * When running automated evaluations, connect `Check` to Stop to gracefully end UI-based scenarios only when a UI is present. ## 🛠ī¸ Troubleshooting * If the environment seems to be headless but `Check` returns FALSE, verify how the scenario was started (some remote desktop or virtual displays may present as GUI). * If you need different behavior for partially-headless setups (e.g., background GPU processes but occasional UI), combine `Check` with manual `Logic Input` to refine control. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.augelab.com/function-blocks/input-output/data-inputs/headless-check.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.