广播代码（C语言）

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <netinet/in.h>
int main(int argc, char const *argv[])
{
    // 1.创建套接字
    int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd < 0)
    {
        perror("sockfd");
        return -1;
    }
    // 2.广播
    int optval = 1;
    setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, (void *)&optval, sizeof(optval));
    // 3.发送数据
    struct sockaddr_in toaddr;
    toaddr.sin_family = AF_INET;
    toaddr.sin_port = htons(8000);
    toaddr.sin_addr.s_addr = htonl("10.9.42.225");
    sendto(sockfd, "hello", strlen("hello"), 0, (struct sockaddr *)&toaddr, sizeof(toaddr));
    // 4.关闭套接字
    close(sockfd);
    return 0;
}