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"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThe webpage provides a comprehensive list of versions for \u003ccode\u003estructgoogle::cloud::pubsub::PullResponse\u003c/code\u003e, ranging from the latest release candidate \u003ccode\u003e2.37.0-rc\u003c/code\u003e down to version \u003ccode\u003e2.11.0\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eThe content describes the behavior of message redelivery in the context of invoking \u003ccode\u003ehandler.nack()\u003c/code\u003e or allowing \u003ccode\u003ehandler\u003c/code\u003e to go out of scope, causing the service to redeliver the message.\u003c/p\u003e\n"],["\u003cp\u003eThe page explains the difference between exactly-once delivery subscriptions, where the message is not redelivered after a successful \u003ccode\u003ehandler.ack()\u003c/code\u003e, and best-efforts subscriptions, where redelivery may still occur.\u003c/p\u003e\n"],["\u003cp\u003eIt also highlights that when a \u003ccode\u003ehandler\u003c/code\u003e is not an rvalue, \u003ccode\u003estd::move(handler).ack()\u003c/code\u003e or \u003ccode\u003estd::move(handler).nack()\u003c/code\u003e might be necessary.\u003c/p\u003e\n"],["\u003cp\u003eThe provided link leads to the Google Cloud documentation about exactly-once delivery.\u003c/p\u003e\n"]]],[],null,[]]
