linux的sendto

ssize_t sendto(int sockfd, const void *buf, size_t len, int flags,
               const struct sockaddr *dest_addr, socklen_t addrlen);

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main() {
    int sockfd;
    struct sockaddr_in servaddr;
    char *message = "Hello, UDP server!";
    
    // 创建 UDP 套接字
    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("socket creation failed");
        exit(EXIT_FAILURE);
    }
    
    memset(&servaddr, 0, sizeof(servaddr));
    
    // 配置服务器地址
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(8080);
    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    
    // 发送数据
    sendto(sockfd, (const char *)message, strlen(message),
           MSG_CONFIRM, (const struct sockaddr *) &servaddr,
           sizeof(servaddr));
    
    printf("UDP message sent.\n");
    
    close(sockfd);
    return 0;
}