有两个电脑,代码在192.168.1.253上运行, 192.168.1.45上运行的是网络调试助手。
addrClient变量不赋值,或者ip地址设为其他错误值,如192.168.1.47,recvfrom依然可以收到192.168.1.45发来的数据;sendto也依然可以发送数据到192.168.1.45,这是为什么??
WORD wVersionRequested;
WSADATA wsaData;
int err;
wVersionRequested=MAKEWORD(2,2);
err = WSAStartup(wVersionRequested, &wsaData);
if (err != 0)
{
return;
}
if (LOBYTE(wsaData.wVersion)!=2 ||
HIBYTE(wsaData.wVersion)!=2)
{
WSACleanup();
return;
}
SOCKET sockSrv=socket(AF_INET,SOCK_DGRAM,0);
SOCKADDR_IN addrSrv;
// addrSrv.sin_addr.S_un.S_addr=htonl(INADDR_ANY);
addrSrv.sin_addr.S_un.S_addr=inet_addr("192.168.1.253");
addrSrv.sin_family=AF_INET;
addrSrv.sin_port=htons(6000);
bind(sockSrv,(SOCKADDR*)&addrSrv,sizeof(SOCKADDR));
SOCKADDR_IN addrClient; //addrClient不赋值也不影响接收和发送,为什么?????
// memset(&addrClient, 0, sizeof(addrClient));
// addrClient.sin_addr.S_un.S_addr=inet_addr("192.168.1.45");
// addrClient.sin_addr.S_un.S_addr=inet_addr("192.168.1.47");
// addrClient.sin_family=AF_INET;
// addrClient.sin_port=htons(8080);
int len=sizeof(SOCKADDR);
char recvBuf[100];
int count = recvfrom(sockSrv,recvBuf,100,0,(SOCKADDR*)&addrClient,&len);
sendto(sockSrv,"nullptr", strlen("nullptr")+1, 0, (SOCKADDR*)&addrClient,len);
for(int i = 0; i < count; i++)
printf("%d\n",recvBuf[i]);
closesocket(sockSrv);
WSACleanup();