{
  "slug": "io-uring-cqe",
  "term": "io_uring completion queue entry",
  "aliases": [
    "io_uring CQE"
  ],
  "definition": "An io_uring completion queue entry is a result record containing an operation result, flags and application-provided identification data.",
  "note": "For ordinary one-shot writes, inspect res for the transferred byte count or a negative error number; a delivered entry alone does not mean success. A submission function's return value is a different result. [overview] [submit]",
  "status": "shipping",
  "advantages": [
    "Lets an application associate completion information with the submitted operation."
  ],
  "limitations": [
    "A successful ordinary buffered write is not itself a power-loss durability guarantee."
  ],
  "related": [
    "io-uring",
    "io-uring-linked-requests",
    "completion-latency",
    "fsync"
  ],
  "supersedes": [],
  "supersededBy": [],
  "firstSeen": null,
  "lastSeen": null,
  "updated": "2026-10-14",
  "citations": [
    {
      "id": "overview",
      "title": "liburing: io_uring(7), result reporting and shared rings.",
      "url": "https://man7.org/linux/man-pages/man7/io_uring.7.html",
      "accessed": "2026-10-14"
    },
    {
      "id": "submit",
      "title": "liburing: io_uring_submit(3), submission return value.",
      "url": "https://man7.org/linux/man-pages/man3/io_uring_submit.3.html",
      "accessed": "2026-10-14"
    },
    {
      "id": "sync",
      "title": "Linux man-pages: fsync(2), error and directory persistence boundaries.",
      "url": "https://man7.org/linux/man-pages/man2/fsync.2.html",
      "accessed": "2026-10-14"
    },
    {
      "id": "hesela-uring",
      "title": "io_uring: completion is not a durable commit",
      "url": "https://hesela.com/analyses/io-uring-completion-ordering-durability/",
      "accessed": "2026-10-14"
    }
  ]
}