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 2025-04-17 UTC."],[[["Version 2.37.0-rc is the latest release candidate for the C++ Pub/Sub library, with version 2.36.0 being the current stable release."],["The documentation provides versioned references for `PullResponse` across multiple releases, spanning from 2.11.0 to the current release candidate, 2.37.0-rc."],["The `PullResponse` is associated with handling the acknowledgment or negative acknowledgment of messages, and the service will redeliver messages if `handler.nack()` is called or the handler goes out of scope."],["The behavior of message redelivery after acknowledgment depends on the subscription type, where exactly-once delivery subscriptions will stop redelivering after a successful `handler.ack()`, while best-effort subscriptions may still redeliver."],["Using `std::move()` on the handler may be required for calling ack() or nack() if the handler is not an rvalue."]]],[]]
