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最近在写一个组播通信的功能,结果发现接受同一台电脑上只能运行一个接收端,如果运行两个时,第二个运行的程序不能收到数据。查找原因是因为没有设置端口数据复用的功能(setsockpot),setsockpot的调用见代码。
//发送端
// Send.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//
#include<WinSock2.h>
#include <iostream>
#include <Ws2tcpip.h>
#pragma comment(lib,"ws2_32.lib")using namespace std;int main()
{WSADATA wsaData = { 0 };WSAStartup(MAKEWORD(2, 2), &wsaData);SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);SOCKADDR_IN sa;sa.sin_family = AF_INET;sa.sin_addr.S_un.S_addr = inet_addr("239.255.88.8");sa.sin_port = htons(6868);int count = 0;char serr[1024] = { 0 };int a = 0;while (1){sprintf_s(serr, "Setsock falied ! %d", count);a = sendto(sock, serr, sizeof(serr), 0, (sockaddr*)&sa, sizeof(sa));if (a > 0){count++;//cout << "send hello lvzai sucessful " << count << endl;cout << serr << endl;}Sleep(20);}return 0;
}
//接收端
// Recv.cpp : 此文件包含 "main" 函数。程序执行将在此处开始并结束。
//
#include<WinSock2.h>
#include <iostream>
#include <Ws2tcpip.h>
#pragma comment(lib,"ws2_32.lib")using namespace std;int main()
{WSADATA wsaData = { 0 };WSAStartup(MAKEWORD(2, 2), &wsaData);SOCKET sock = socket(AF_INET, SOCK_DGRAM, 0);SOCKADDR_IN addr_rec;addr_rec.sin_family = AF_INET;addr_rec.sin_addr.S_un.S_addr = htonl(INADDR_ANY); addr_rec.sin_port = htons(6868);bool bOptval = true;int iret = 0;iret = setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (char*)&bOptval, sizeof(bOptval));if (iret != 0)cout << "setsockopt fail: " << WSAGetLastError() << endl;iret = bind(sock, (SOCKADDR*)&addr_rec, sizeof(addr_rec));if (iret != 0){char serr[1024] = { 0 };sprintf_s(serr, "kbind falied ! %d", WSAGetLastError());cout << "bind fail" << endl;return -1;}struct ip_mreq mreq;mreq.imr_interface.s_addr = htonl(INADDR_ANY);; //inet_addr("169.254.4.119");mreq.imr_multiaddr.s_addr = inet_addr("239.255.88.8");if (setsockopt(sock,IPPROTO_IP, IP_ADD_MEMBERSHIP, (const char*)&mreq, sizeof(mreq)) !=0){char serr[1024] = { 0 };sprintf_s(serr, "Setsock falied ! %d", WSAGetLastError());cout << "加入组播失败!" <<serr << endl;}int len = sizeof(SOCKADDR);int res = 0;char strRecv[1024] = { 0 };int coutt = 0;while (1){res = recvfrom(sock, strRecv, sizeof(strRecv), 0, (SOCKADDR*)&addr_rec, &len);if (res > 0){coutt++;cout << "recv Data : " << strRecv << " coutt: " << coutt << endl;}}return 0;
}
其中最关键的是setsockopt函数的使用。
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