After a publisher flushes a batch of messages the batch is (obviously) not received immediately by the service. While the batch remains pending it potentially consumes memory resources in the client (and/or the service).
Some applications may have constraints on the number of bytes and/or messages they can tolerate in this pending state, and may prefer to block or reject messages.
[[["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complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14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 content provides a list of C++ Pub/Sub library versions, 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\u003eEach version listed links to documentation for the \u003ccode\u003eMaxPendingMessagesOption\u003c/code\u003e struct within that specific release.\u003c/p\u003e\n"],["\u003cp\u003e\u003ccode\u003eMaxPendingMessagesOption\u003c/code\u003e controls the maximum number of messages a publisher can have pending, and this limits the amount of memory that pending messages consume in the client and service.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003eMaxPendingMessagesOption\u003c/code\u003e type is an alias of \u003ccode\u003estd::size_t\u003c/code\u003e, an unsigned integer type.\u003c/p\u003e\n"]]],[],null,[]]
