我刚开始学习C语言，我正在尝试处理Windows套接字。
问题是服务器只能接受和发送一次消息。我使用了调试模式，并从服务器部分看到工作在select((中停止。在客户端中似乎很好(但我不确定(，并且在我的代码中看不到问题。但我有这样的结果。怎么了？
我注意到我的tv.tv_sec没有定义，我在选择之前就这样做了，没有任何变化。
可以肯定的是：由于我需要接收和发送消息，所以我不需要 accept(( 中的写描述符，对吧？
客户端使用CreateThread函数，我尝试发送消息。发送在 while(1( 周期中 main((
服务器部分：
int main(int argc, char* argv[])
{
/* definitions, WSAStartup(), socket(), bind(), listen()
Listening socket is a returned value of listen() function*/
FD_ZERO(&readSet);
FD_ZERO(&writeSet);
while (1)
{
// SELECT (LISTENING SOCKET)
FD_ZERO(&readSet);
FD_SET(listeningSocket, &readSet);
tv.tv_sec = 5;
printf("Listening: Read FD: %d; Write FD : %d;n", FD_ISSET(listeningSocket, &readSet), FD_ISSET(listeningSocket, &writeSet));
if ((retVal = select(listeningSocket + 1, &readSet, NULL, NULL, 0)) == SOCKET_ERROR)
{
printf("Select error ");
break;
}
else if (retVal == 0)
{
printf(". . .n");
continue;
}
else
{
// READ SD
if ((FD_ISSET(listeningSocket, &readSet)) != SOCKET_ERROR)
{
if ((newSocketDescriptor = accept(listeningSocket, (struct sockaddr *)&clientAddr, &clientAddrSize)) == SOCKET_ERROR)
{
printf("Accept error ");
break;
}
FD_ZERO(&readSet);
FD_SET(newSocketDescriptor, &readSet);
HOSTENT *hst = gethostbyaddr((const char *)&serverAddr.sin_addr.s_addr, 4, AF_INET);
printf("Welcome %s (%s:%d) new connectedn", hst->h_name, inet_ntoa(clientAddr.sin_addr), ntohs(clientAddr.sin_port));
printf("Read FD: %d; Write FD : %d;n", FD_ISSET(newSocketDescriptor, &readSet), FD_ISSET(newSocketDescriptor, &writeSet));
// READ
if (FD_ISSET(newSocketDescriptor, &readSet) != 0)
{
if ((numBytes = recv(newSocketDescriptor, &bufferData[0], sizeof(bufferData), 0)) == SOCKET_ERROR)
{
printf("Recv failed n");
freeSocketInformation(newSocketDescriptor);
break;
}
bufferData[numBytes] = ' ';
printf("Client -> Server: %sn", &bufferData[0]);
}
// WRITE
FD_ZERO(&writeSet);
FD_SET(newSocketDescriptor, &writeSet);
printf("Read FD: %d; Write FD : %d;n", FD_ISSET(newSocketDescriptor, &readSet), FD_ISSET(newSocketDescriptor, &writeSet));
if (FD_ISSET(newSocketDescriptor, &writeSet) != 0)
{
//fgets(&bufferData[0], sizeof(bufferData), stdin);
if (send(newSocketDescriptor, &bufferData[0], strlen(&bufferData[0]), 0) == SOCKET_ERROR)
{
printf("Send error ");
freeSocketInformation(newSocketDescriptor);
break;
}
bufferData[numBytes] = ' ';
printf("Server -> Client: %sn", &bufferData[0]);
}
printf("Read FD: %d; Write FD : %d;n", FD_ISSET(newSocketDescriptor, &readSet), FD_ISSET(newSocketDescriptor, &writeSet));
FD_SET(newSocketDescriptor, &readSet);
}
}
}
//FD_CLR(listeningSocket, &readSet);
closesocket(newSocketDescriptor);
} while (FALSE);
printf("- Error code: %dn", WSAGetLastError());
closesocket(listeningSocket);
WSACleanup();
return 0;
}
客户端部分(它使用代码末尾的 CreateThread 函数(：
/* definitions, socket(), connect()*/
if (ioctlsocket(socketDescriptor, FIONBIO, (unsigned long *)&nb) != 0)
{
printf("ioctlsocket error ");
break;
}
FD_ZERO(&writeSet);
FD_SET(socketDescriptor, &writeSet);
if ((retVal = select(socketDescriptor + 1, NULL, &writeSet, NULL, &tv)) == SOCKET_ERROR)
{
printf("Send non-blocking error ");
break;
}
else if (retVal == 0)
{
printf("Non-blocking connect time limit is expired");
break;
}
}
printf("Connection with %sn", SERVERADDR);
DWORD thID;
printf("Socket Desciptor: %dn", socketDescriptor);
HANDLE hThread = CreateThread(NULL, NULL, HandleReadThread, (LPVOID)socketDescriptor, NULL, &thID);
printf("Thread ID: %dn", thID);
while (1)
{
// WRITE
printf("Client -> Server: ");
fgets(&bufferData[0], sizeof(bufferData), stdin);
FD_ZERO(&writeSet);
FD_SET(socketDescriptor, &writeSet);
tv.tv_sec = 5;
if ((retVal = select(socketDescriptor + 1, NULL, &writeSet, NULL, &tv)) == SOCKET_ERROR)
{
printf("Send non-blocking error ");
break;
}
if (FD_ISSET(socketDescriptor, &writeSet) != 0)
{
if (send(socketDescriptor, bufferData, strlen(&bufferData[0]), 0) == SOCKET_ERROR)
{
printf("Send error ");
break;
}
}
}
} while (FALSE);
printf("- Error code: %dn", WSAGetLastError());
closesocket(socketDescriptor);
WSACleanup();
return 0;
}
DWORD WINAPI HandleReadThread(LPVOID serverSocket)
{
SOCKET socketDescriptor;
socketDescriptor = (SOCKET)serverSocket;
char bufferData[MAXDATASIZE] = { 0 };
int retVal;
fd_set readSet;
timeval tv = { 0 };
tv.tv_sec = 5;
int numBytes;
int nclients = 0;
while (1)
{
FD_ZERO(&readSet);
FD_SET(socketDescriptor, &readSet);
if ((retVal = select(socketDescriptor + 1, &readSet, NULL, NULL, &tv)) == SOCKET_ERROR)
{
printf("Select error. Error code: %d", WSAGetLastError());
break;
}
else if (retVal == 0)
{
//printf(". . .n");
continue;
}
else
{
//FD_ZERO(socketDescriptor, &readSet);
//FD_SET(socketDescriptor, &readSet);
// READ
if (FD_ISSET(socketDescriptor, &readSet) != 0)
{
if ((numBytes = recv(socketDescriptor, &bufferData[0], sizeof(bufferData), 0)) == SOCKET_ERROR)
{
printf("Recv error in Thread. Error code: %dn", WSAGetLastError());
break;
}
printf("nSocket Desciptor: %dn", socketDescriptor);
bufferData[numBytes] = ' ';
printf("Server -> Client: %sn", &bufferData[0]);
}
}
}
closesocket(socketDescriptor);
return 0;
}
好吧，我自己解决了。条件
if ((FD_ISSET(listeningSocket, &readSet)) != 0)
工作了所有 while(1( 循环，它应该在 accept(( 函数之后完成。此外，我在 while(1( 的开头为 readSet 添加了这些行FD_SET：
if (newSocketDescriptor)
{
FD_SET(newSocketDescriptor, &readSet);
}
聊天开始工作，但有很多事情要做:)