If the application invokes handler.nack() or allows handler to go out of scope, then the service will redeliver the message.
With exactly-once delivery subscriptions, the service will stop redelivering the message once the application invokes handler.ack() and the invocation succeeds. With best-efforts subscriptions, the service may redeliver the message, even after a successful handler.ack() invocation.
If handler is not an rvalue, you may need to use std::move(handler).ack() or std::move(handler).nack().
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-03-14 UTC."],[[["The latest release candidate version is 2.37.0-rc, and a list of all available versions from 2.36.0 to 2.11.0 are provided."],["This page documents the `PullResponse` structure within the Google Cloud Pub/Sub C++ library."],["Messages can be redelivered by the service if the application uses `handler.nack()` or if `handler` goes out of scope."],["The service will cease redelivering messages for exactly-once delivery subscriptions once the application successfully calls `handler.ack()`."],["Best-efforts subscriptions may still redeliver messages, even after a successful `handler.ack()`."]]],[]]
