UDP单播

CMakeLists.txt文件中添加如下行：

link_libraries(ws2_32)

1.发送端

#include <iostream>
#include <winsock2.h>
#include <cstdio>#pragma comment(lib, "Ws2_32.lib")  // Link with ws2_32.libint main() {1.Initialize winsockWSADATA wsaData;int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);if (iResult != NO_ERROR) {wprintf(L"WSAStartup failed with error: %d\n", iResult);return 1;}2.Create a socket for sending dataSOCKET SendSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);if (SendSocket == INVALID_SOCKET) {wprintf(L"socket failed with error: %1d\n", WSAGetLastError());WSACleanup();return 1;}3.Set up the RecvAddr structure with the IP address of the receiver (in this example case "192.168.1.1")and the specified port number.sockaddr_in RecvAddr = {0};unsigned short Port = 27015;RecvAddr.sin_family = AF_INET;RecvAddr.sin_port = htons(Port);RecvAddr.sin_addr.s_addr = inet_addr("127.0.0.1");4.Send a datagram to the receiverwprintf(L"Sending a datagram to the receiver...\n");char sendBuf[1024]="Hello";int BufLen = 1024;iResult = sendto(SendSocket, sendBuf, BufLen, 0, reinterpret_cast<SOCKADDR *>(&RecvAddr), sizeof(RecvAddr));if (iResult == SOCKET_ERROR) {wprintf(L"sendto failed with error: %d\n", WSAGetLastError());closesocket(SendSocket);WSACleanup();return 1;}5.When the application is finished sending, close the socket.wprintf(L"Finished sending. Closing socket. \n");iResult = closesocket(SendSocket);if (iResult == SOCKET_ERROR) {wprintf(L"closesocket failed with error: %d\n", WSAGetLastError());WSACleanup();return 1;}6.Clean up and quit.wprintf(L" Exiting.\n");WSACleanup();return 0;
}

2.接收端代码

#include <iostream>
#include <winsock2.h>
#include <cstdio>#pragma comment(lib, "Ws2_32.lib")  // Link with ws2_32.libint main() {1.Initialize winsockWSADATA wsaData;int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);if (iResult != NO_ERROR) {wprintf(L"WSAStartup failed with error: %d\n", iResult);return 1;}2.Create a receiver socket to receive datagramsSOCKET RecvSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);if (RecvSocket == INVALID_SOCKET) {wprintf(L"socket failed with error: %1d\n", WSAGetLastError());return 1;}3.Bind the socket to any address and the specified port.sockaddr_in RecvAddr = {0};unsigned short Port = 27015;RecvAddr.sin_family = AF_INET;RecvAddr.sin_port = htons(Port);RecvAddr.sin_addr.s_addr = htonl(INADDR_ANY);iResult=bind(RecvSocket,reinterpret_cast<SOCKADDR*>(&RecvAddr), sizeof(RecvAddr));if (iResult != 0) {wprintf(L"bind failed with error: %d\n", WSAGetLastError());return 1;}4.Call the recvfrom function to receive datagrams on the bound socket.wprintf(L"Receiving datagrams...\n");char RecvBuf[1024];int RecvAddrSize=sizeof(RecvAddr);iResult = recvfrom(RecvSocket, RecvBuf, sizeof(RecvBuf), 0, reinterpret_cast<SOCKADDR *>(&RecvAddr), &RecvAddrSize);if (iResult == SOCKET_ERROR) {wprintf(L"recvfrom failed with error: %d\n", WSAGetLastError());} else{printf("%s\n",RecvBuf);}5.Close the socket when finished receiving datagramswprintf(L"Finished receiving. Closing socket. \n");iResult = closesocket(RecvSocket);if (iResult == SOCKET_ERROR) {wprintf(L"closesocket failed with error: %d\n", WSAGetLastError());WSACleanup();return 1;}6.Clean up and quit.wprintf(L" Exiting.\n");WSACleanup();return 0;
}

执行结果：