sendmmsg(2) - wariua/manpages-ko GitHub Wiki

#define _GNU_SOURCE         /* feature_test_macros(7) 참고 */
#include <sys/socket.h>

int sendmmsg(int sockfd, struct mmsghdr *msgvec, unsigned int vlen,
             int flags);

struct mmsghdr {
    struct msghdr msg_hdr;  /* 메시지 헤더 */
    unsigned int  msg_len;  /* 전송한 바이트 수 */
};

#define _GNU_SOURCE
#include <netinet/ip.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>

int
main(void)
{
    int sockfd;
    struct sockaddr_in addr;
    struct mmsghdr msg[2];
    struct iovec msg1[2], msg2;
    int retval;

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd == -1) {
        perror("socket()");
        exit(EXIT_FAILURE);
    }

    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    addr.sin_port = htons(1234);
    if (connect(sockfd, (struct sockaddr *) &addr, sizeof(addr)) == -1) {
        perror("connect()");
        exit(EXIT_FAILURE);
    }

    memset(msg1, 0, sizeof(msg1));
    msg1[0].iov_base = "one";
    msg1[0].iov_len = 3;
    msg1[1].iov_base = "two";
    msg1[1].iov_len = 3;

    memset(&msg2, 0, sizeof(msg2));
    msg2.iov_base = "three";
    msg2.iov_len = 5;

    memset(msg, 0, sizeof(msg));
    msg[0].msg_hdr.msg_iov = msg1;
    msg[0].msg_hdr.msg_iovlen = 2;

    msg[1].msg_hdr.msg_iov = &msg2;
    msg[1].msg_hdr.msg_iovlen = 1;

    retval = sendmmsg(sockfd, msg, 2, 0);
    if (retval == -1)
        perror("sendmmsg()");
    else
        printf("%d messages sent\n", retval);

    exit(0);
}