CQE: Completion Queue Event

There is a completion queue event (CQE) added by the kernel for each submission queue entry that is submitted. The CQE contains the status of the operation submitted as part of the SQE. There is exactly one CQE added to the completion queue as a result of the kernel processing an SQE. There is a one-to-one correlation between the two.

Note

This structure is part of the raw io_uring interface and is defined in io_uring.h.

struct io_uring_cqe

struct io_uring_cqe {
    __u64   user_data;      /* sqe->data submission passed back */
    __s32   res;            /* result code for this event */
    __u32   flags;
};