#include <stdio.h>#include <stdlib.h>#include <windows.h>#include <winsock.h>#pragma comment(lib, "ws2_32.lib")#define close closesocket#undef IP_ADD_MEMBERSHIP#define IP_ADD_MEMBERSHIP 12int main(void){        WSADATA wsa={0};    WSAStartup(MAKEWORD(2,2),&wsa);    SOCKET fd;    SOCKADDR_IN localif;        fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);    if (fd == -1) {        perror("socket");        return -1;    }    localif.sin_family = AF_INET;    localif.sin_port   = htons(1234);    localif.sin_addr.s_addr = htonl(INADDR_ANY);    if (bind(fd, (SOCKADDR *)&localif, sizeof(localif)) == -1) {        perror("bind");        return -1;        }    int ttl = 1;    if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, (char *)&ttl, sizeof(ttl)) == SOCKET_ERROR) {        printf("setsockopt IP_MULTICAST_TTL %d", WSAGetLastError());                return -1;        }    struct ip_mreq mreq;    memset(&mreq, 0, sizeof(mreq));    mreq.imr_interface.s_addr = inet_addr("192.168.1.145");    mreq.imr_multiaddr.s_addr = inet_addr("234.0.0.1"); //234.5.6.7    if (setsockopt(fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mreq, sizeof(mreq)) == -1) {        printf("setsockopt IP_ADD_MEMBERSHIP %d", WSAGetLastError());                return -1;        }    while (true) {        char buf[1024] = {0};        int n = recv(fd, buf, sizeof(buf), 0);        if (n == -1) {            perror("recv");            return -1;        }        buf[n] = 0;        printf("%s", buf);    }    if (setsockopt(fd, IPPROTO_IP, IP_DROP_MEMBERSHIP, (char *)&mreq, sizeof(mreq)) == -1) {        printf("setsockopt IP_DROP_MEMBERSHIP %d", WSAGetLastError());        return -1;        }    WSACleanup();    return 0;}