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

#define PAYLOAD "Hello, World!"

int main() {
    int sockfd;
    char *payload = PAYLOAD;
    struct sockaddr_in servaddr;

    if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
        perror("Create socket failed.\n");
        exit(EXIT_FAILURE);
    }

    memset(&servaddr, 0, sizeof(servaddr));

    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(4321);
    servaddr.sin_addr.s_addr = inet_addr("1.2.3.4");

    sendto(sockfd, (const char *)payload, strlen(payload),
        MSG_CONFIRM, (const struct sockaddr *) &servaddr,
            sizeof(servaddr));

    close(sockfd);
    return 0;
}