struct io_uring_sq {
    unsigned *khead;
    unsigned *ktail;
    unsigned *kflags;
    unsigned *kdropped;
    unsigned *array;
    struct io_uring_sqe *sqes;
?
    unsigned sqe_head;
    unsigned sqe_tail;
?
    size_t ring_sz;
    void *ring_ptr;
?
    unsigned ring_mask;
    unsigned ring_entries;
?
    unsigned pad[2];
};

cd liburing-master
./configure
make -j
sudo make install

#include <stdio.h>
#include <liburing.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
?
#define BUFFER_LENGTH   1024
#define ENTRIES_LENGTH  1024
?
#define EVENT_ACCEPT    0
#define EVENT_READ      1
#define EVENT_WRITE     2
?
// io事件信息
struct req_info{
    int fd;
    int event;
};
?
// 初始化tcp fd
int init_server(unsigned int port){
    int socket_fd = socket(AF_INET, SOCK_STREAM, 0);
    struct sockaddr_in serveraddr;
    memset(&serveraddr, 0, sizeof(struct sockaddr_in));
    serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_port = htons(port);
    if(-1 == bind(socket_fd, (struct sockaddr *)&serveraddr, sizeof(struct sockaddr))){
        perror("bind error!\n");
    }
    listen(socket_fd, 10);
    return socket_fd;
}
?
// 設(shè)置accept事件
int set_event_accept(struct io_uring *ring, int sockfd, struct sockaddr* addr, socklen_t *addrlen, int flags){
    struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
?
    struct req_info accept_info = {
        .fd = sockfd,
        .event = EVENT_ACCEPT
    };
?
    memcpy(&sqe->user_data, &accept_info, sizeof(struct req_info));
    io_uring_prep_accept(sqe, sockfd, addr, addrlen, flags);
?
    return 0;
}
?
// 設(shè)置recv事件
int set_event_recv(struct io_uring *ring, int sockfd, void *buf, size_t len, int flags){
    struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
?
    struct req_info recv_info = {
        .fd = sockfd,
        .event = EVENT_READ
    };
?
    memcpy(&sqe->user_data, &recv_info, sizeof(struct req_info));
    io_uring_prep_recv(sqe, sockfd, buf, len, flags);
?
    return 0;
}
?
// 設(shè)置send事件
int set_event_send(struct io_uring *ring, int sockfd, void *buf, size_t len, int flags){
    struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
?
    struct req_info send_info = {
        .fd = sockfd,
        .event = EVENT_WRITE
    };
?
    memcpy(&sqe->user_data, &send_info, sizeof(struct req_info));
    io_uring_prep_send(sqe, sockfd, buf, len, flags);
?
    return 0;
}
?
int main(int argc, void *argv[]){
    unsigned int port = 9999;
    int sockfd = init_server(port);
?
    struct io_uring_params params;
    memset(&params, 0, sizeof(struct io_uring_params));
    // 初始化io_uring 其中包含了sq和cq
    struct io_uring ring;
?
    io_uring_queue_init_params(ENTRIES_LENGTH, &ring, &params);
?
    struct sockaddr_in clientaddr;
    socklen_t len = sizeof(clientaddr);
    set_event_accept(&ring, sockfd, (struct sockaddr*)&clientaddr, &len, 0);
?
    while(1){
        char buffer[BUFFER_LENGTH] = {0};
?
        // 事件提交
        io_uring_submit(&ring);
?
        // 等待事件完成，其他開發(fā)場景下非必要情況無需等待
        struct io_uring_cqe *cqe;
        io_uring_wait_cqe(&ring, &cqe);
?
        // 獲取完成事件
        struct io_uring_cqe *cqe_list[128];
        int nready = io_uring_peek_batch_cqe(&ring, cqe_list, 128);
        // echo邏輯處理
        for(int i = 0; i < nready; ++i){
            struct io_uring_cqe *entries = cqe_list[i];
            struct req_info result;
            memcpy(&result, &entries->user_data, sizeof(struct req_info));
            if(result.event == EVENT_ACCEPT){
                printf("accept client\n");
                set_event_accept(&ring, sockfd, (struct sockaddr*)&clientaddr, &len, 0);
?
                int connfd = entries->res;
?
                set_event_recv(&ring, connfd, buffer, BUFFER_LENGTH, 0);
            }else if(result.event == EVENT_READ){
                int connfd = entries->res;
                if(connfd == 0){
                    printf("close fd:%d\n", result.fd);
                    close(result.fd);
                }else if(connfd > 0){
                    printf("recv: len:%d, data:%s\n", connfd, buffer);
                    set_event_send(&ring, result.fd, buffer, connfd, 0);
                }else{
                    printf("error recv!\n");
                    close(result.fd);
                }
            }else if(result.event == EVENT_WRITE){
                int ret = entries->res;
                printf("set_event_send ret: %d, %s\n", ret, buffer);
                set_event_recv(&ring, result.fd, buffer, BUFFER_LENGTH, 0);
            }
        }
?
        // 清除完成隊列中完成表項，以免事件重復(fù)處理
        io_uring_cq_advance(&ring, nready);
    }
?
    return 0;
}