C++ Winsock接收到的字节数无效
在尝试验证接收的字节数时,我当前面临一个与Winsock相关的问题 在我的应用程序中,我使用一个非阻塞套接字来抛出我自己的C++ Winsock接收到的字节数无效,c++,c++11,winsock,C++,C++11,Winsock,在尝试验证接收的字节数时,我当前面临一个与Winsock相关的问题 在我的应用程序中,我使用一个非阻塞套接字来抛出我自己的Timeout异常。下面是初始化Winsock的相应代码: // Initialize Winsock WSAData winSockData; WORD dllVersion = MAKEWORD(2, 1); long iResult = WSAStartup(dllVersion, &winSockData); if (iResult != NO_ERROR)
Timeout
异常。下面是初始化Winsock
的相应代码:
// Initialize Winsock
WSAData winSockData;
WORD dllVersion = MAKEWORD(2, 1);
long iResult = WSAStartup(dllVersion, &winSockData);
if (iResult != NO_ERROR)
return;
addrinfo* serverAddress = nullptr;
addrinfo* ptr = nullptr, hints;
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_INET;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
iResult = getaddrinfo("127.0.0.1", "10011", &hints, &serverAddress);
if (iResult != 0)
return;
// Create communication socket
SOCKET connectSocket = socket(AF_INET, SOCK_STREAM, /*IPPROTO_TCP*/0);
if (connectSocket == INVALID_SOCKET)
return;
// Establish connection to server
iResult = connect(connectSocket, serverAddress->ai_addr, (int)serverAddress->ai_addrlen);
if (iResult == SOCKET_ERROR)
return;
// Set socket to non-blocking
ULONG mode = 1;
m_iResult = ioctlsocket(m_connectSocket, FIONBIO, &mode);
if (m_iResult == SOCKET_ERROR)
return;
// server address info not needed anymore
freeaddrinfo(serverAddress);
应用程序首先连接到给定的telnet服务器,发送请求,然后等待相应的响应消息
传入数据存储在一个适当的字符数组中,称为m_serverMsg
(固定大小为BUFSIZE
,当前设置为4200字节)
如果检索服务器响应消息的时间过长(存储在g_requestTimeout
中的最大允许时间),则会抛出我自己的TimeoutException
如果在消息缓冲区中找到换行符(\r\n
),则给定的服务器消息已到达其结尾
但是,以下用于检索服务器响应消息的部分未按预期工作。预期的传入数据字节为1040
,但实际字节始终为3435973836
unsigned long long startTime = getWallTimeInMs();
bool retry = true;
unsigned int receivedBytes = 0;
// Fetch server response
do
{
try
{
m_iResult = fetchMessage(m_connectSocket, m_serverMsg, int(BUFSIZE - receivedBytes));
if (m_iResult == SOCKET_ERROR)
throw std::exception();
if (m_iResult > 0)
{
for (unsigned int i = receivedBytes; i < receivedBytes + m_iResult; i++)
{
char* eol = strstr(m_serverMsg, "\r\n");
if (eol)
{
retry = false;
break;
}
}
receivedBytes += m_iResult;
}
}
catch (CommException e)
{
// in case there's a short delay in retrieving the server response message
if (getWallTimeInMs() - startTime < g_requestTimeout)
Sleep(20);
else
// response timeout exceeded; connection has been lost
throw CommException("server not responding in time.", CommProblem::ConnectionLost);
}
catch (std::exception& e)
{
std::cout << "There was a socket related problem." << std::endl;
std::cout << "Error code: " << WSAGetLastError() << std::endl;
}
} while (retry);
这部分
for (unsigned int i = receivedBytes; i < receivedBytes + m_iResult; i++)
{
if (m_serverMsg[i] == '\r\n')
{
retry = false;
break;
}
}
或者将m_serverMsg
转换为std::string
并使用find
方法
if(std::string(m_serverMsg, receivedBytes, m_iResult).find("\r\n") != std::string::npos)
{
retry = false;
break;
}
显示
fetchMessage
。您在m\u iResult
中获得了3435973836
?什么时候<代码>中断将只停止您的循环
操作,而不停止执行
循环。您的错误在消息中。3435973836是十六进制的0xCCCC。编译器在调试模式下使用此值填充未初始化的变量。如果需要帮助,请显示fetchMessage。在调试窗口中,它显示form_serverMsg
:@NikolayKondratyevm_iResult
是一个类成员变量,每次在try{}块内都会为其赋值:m_iResult=fetchMessage(…)代码>\r\n
不是“回车符”,而是两个字节的CR/LF序列。注意:在eWoldBlock上没有“连接延迟”,将其与“连接丢失”关联也是非常不正确的。很高兴知道,thx。但是接收的字节数仍然存在问题。@neuronal.bit所以3435973836
是fetchMessage
call之后m_iResult
的值吗?这是正确的。如果fetchMessage()
本身抛出异常,则在将接收到的字节数分配给m_iResult
之前会捕获该异常。因此,m_iResult
应始终包含实际接收的字节数,以防出现错误。@neuronal.bit尝试添加调试输出,例如printf(“recv返回%d\n”,结果)调用recv
之后的fetchMessage
中的code>。有趣的是,在fetchMessage()
中,返回值是356
,但分配给m\u iResult
时,返回值是3435973836
m_iResult
的类型为int
。
char* eol = strstr(m_serverMsg, "\r\n");
if(eol != NULL)
{
retry = false;
break;
}
if(std::string(m_serverMsg, receivedBytes, m_iResult).find("\r\n") != std::string::npos)
{
retry = false;
break;
}