windows下c++upd收发广播信息示例代码

以下是Windows下C++实现UDP收发广播信息的示例代码：

发送端代码：

#include <iostream>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")

using namespace std;

int main()
{
    // 初始化Winsock
    WSADATA wsaData;
    int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != 0) {
        cout << "WSAStartup failed: " << iResult << endl;
        return 1;
    }

    // 创建socket
    SOCKET sendSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (sendSocket == INVALID_SOCKET) {
        cout << "Failed to create socket: " << WSAGetLastError() << endl;
        WSACleanup();
        return 1;
    }

    // 设置广播属性
    BOOL bOptVal = TRUE;
    iResult = setsockopt(sendSocket, SOL_SOCKET, SO_BROADCAST, (char*)&bOptVal, sizeof(BOOL));
    if (iResult == SOCKET_ERROR) {
        cout << "setsockopt failed: " << WSAGetLastError() << endl;
        closesocket(sendSocket);
        WSACleanup();
        return 1;
    }

    // 设置目标地址
    SOCKADDR_IN destAddr;
    destAddr.sin_family = AF_INET;
    destAddr.sin_port = htons(12345);
    destAddr.sin_addr.s_addr = INADDR_BROADCAST;

    // 发送数据
    char sendBuf[] = "Hello, this is a broadcast message";
    iResult = sendto(sendSocket, sendBuf, strlen(sendBuf), 0, (SOCKADDR*)&destAddr, sizeof(destAddr));
    if (iResult == SOCKET_ERROR) {
        cout << "sendto failed: " << WSAGetLastError() << endl;
        closesocket(sendSocket);
        WSACleanup();
        return 1;
    }

    // 关闭socket
    closesocket(sendSocket);
    WSACleanup();

    return 0;
}

接收端代码：

#include <iostream>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")

using namespace std;

int main()
{
    // 初始化Winsock
    WSADATA wsaData;
    int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
    if (iResult != 0) {
        cout << "WSAStartup failed: " << iResult << endl;
        return 1;
    }

    // 创建socket
    SOCKET recvSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (recvSocket == INVALID_SOCKET) {
        cout << "Failed to create socket: " << WSAGetLastError() << endl;
        WSACleanup();
        return 1;
    }

    // 设置广播属性
    BOOL bOptVal = TRUE;
    iResult = setsockopt(recvSocket, SOL_SOCKET, SO_BROADCAST, (char*)&bOptVal, sizeof(BOOL));
    if (iResult == SOCKET_ERROR) {
        cout << "setsockopt failed: " << WSAGetLastError() << endl;
        closesocket(recvSocket);
        WSACleanup();
        return 1;
    }

    // 设置本地地址
    SOCKADDR_IN localAddr;
    localAddr.sin_family = AF_INET;
    localAddr.sin_port = htons(12345);
    localAddr.sin_addr.s_addr = INADDR_ANY;

    // 绑定socket
    iResult = bind(recvSocket, (SOCKADDR*)&localAddr, sizeof(localAddr));
    if (iResult == SOCKET_ERROR) {
        cout << "Failed to bind socket: " << WSAGetLastError() << endl;
        closesocket(recvSocket);
        WSACleanup();
        return 1;
    }

    // 接收数据
    char recvBuf[1024] = { 0 };
    SOCKADDR_IN fromAddr;
    int fromLen = sizeof(fromAddr);
    iResult = recvfrom(recvSocket, recvBuf, sizeof(recvBuf), 0, (SOCKADDR*)&fromAddr, &fromLen);
    if (iResult == SOCKET_ERROR) {
        cout << "recvfrom failed: " << WSAGetLastError() << endl;
        closesocket(recvSocket);
        WSACleanup();
        return 1;
    }

    // 显示收到的数据
    cout << "Received message: " << recvBuf << endl;

    // 关闭socket
    closesocket(recvSocket);
    WSACleanup();

    return 0;
}

这个示例代码实现了在本地网络中发送广播消息，并在另一台机器上接收。要注意的是，如果有多台机器在同一个局域网下运行这个示例代码，那么它们都会收到这个广播消息。