我尝试通过UDP从计算机发送数据到另一台计算机(第一台计算机:Ubuntu,C++与Eclipse,第二台计算机Windows 10 Matlab 2014b)。 C++计算机应该作为服务器工作。从C++发送数据到Matlab工作正常,但我不能以相反的方向发送数据。每当我的C++程序到达recvfrom()时,即使matlab一遍又一遍地发送数据,它将在此时闲置而不再执行任何操作。我尝试通过netcat在ubuntu上接收数据,同时发送包与Matlab,并且工作正常。即使我用select()尝试了一些东西,但是这只会导致在程序到达select()时等待10s,然后再次在recvfrom处冻结。如果有人能给我一些帮助,我将非常感激。套接字UDP程序在recvfrom停止
int Socket=socket(AF_INET, SOCK_DGRAM,0);
/*FD_ZERO(&SockSet);
FD_SET(Socket,&SockSet);
sTimeval.tv_sec=0.1;
sTimeval.tv_usec=0;
int status=select(Socket+1,&SockSet,(fd_set*)NULL,(fd_set *)NULL,&sTimeval);
cout<<status<<endl;*/
if(Socket!=-1)
cout<<"Socket created"<<endl;
else
cout<<"Socket not created"<<endl;
unsigned short port=4012;
struct in_addr serverIP;
//(void)inet_pton(AF_INET,"192.168.56.100", &clientIP);
(void)inet_pton(AF_INET,"192.168.56.101", &serverIP);
struct sockaddr_in server;
memset(&server,0, sizeof(server));
server.sin_family=AF_INET;
server.sin_addr=serverIP;
server.sin_port=htons(port);
if(bind(Socket,(struct sockaddr*)&server, sizeof(&server))!=1)
cout<<"Binding successful"<<endl;
else
cout<<"Binding failed";
struct sockaddr client;
memset(&client, 0, sizeof(client));
socklen_t clientlen=0;
struct sockaddr_in* client_in;
memset(&client_in,0,sizeof(client_in));
cout<<"warten vor recv"<<endl;
ssize_t bytesread=recvfrom(Socket, &msg, sizeof(msg), 0, &client,&clientlen);
cout<<(int)bytesread<<endl;
cout<<msg<<endl;
client_in=(struct sockaddr_in*)&client;
char* client_adr=inet_ntoa(client_in->sin_addr);
printf("%s Port%d\n", client_adr, ntohs(client_in->sin_port));
if (bytesread == -1) {
cerr << "Fehler beim empfangen" << endl;
int status = close(Socket);
if (status == 0)
cout << "Socket closed" << endl;
else if (status == -1)
cout << "Socket not closed" << endl;
return (1);
}
//Wenn Infos ueber Client nicht schon vorher aus recvfrom()
/*struct in_addr clientIP;
(void)inet_pton(AF_INET,"192.168.2.102", &clientIP);
struct sockaddr_in client;
memset(&client,0, sizeof(client));
client.sin_family=AF_INET;
client.sin_addr=clientIP;
client.sin_port=htons(portwindows);*/
char msg2[]="12345";
ssize_t bytessent=sendto(Socket,msg2,strlen(msg2),0,(struct sockaddr*)&client,sizeof(client));
cout<<(int)bytessent<< " bytes were sent"<<endl;
int status=close(Socket);
if(status==0)
cout<<"Socket closed"<<endl;
else if(status==-1)
cout<<"Socket not closed"<<endl;
192.168.56.101,是unix盒子还是matlab盒子? – pm100
如果您不希望recvfrom()阻塞,直到收到一些数据,那么您需要将套接字设置为非阻塞模式。 (在这个网站的搜索框中搜索非阻塞,你会看到很多关于如何做到这一点的问题和答案)。 –
感谢您的回答。我已经尝试将套接字设置为非阻塞模式,然后我的程序不再冻结。但问题是我通过Matlab发送数据,所以recvfrom()应该得到一些数据,然后程序应该走得更远。但你能看出为什么这不会发生?正如我所说,当我通过matlab发送数据并用netcat测试数据是否到达C++计算机时,一切都很好。 – Jannik