SOCKET_ERROR & INVALID_SOCKET & WSAGetLastError

本文详细解析了在Windows环境下编程中遇到的INVALID_SOCKET问题及其具体值,并介绍了如何使用WSAGetLastError()来获取和处理套接字错误。

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SOCKET_ERROR

http://www.cnblogs.com/onroad/archive/2009/08/10/1543164.html


INVALID_SOCKET

INVALID_SOCKET的值不是-1,原因参考basetsd.hWinSock2.h

 

typedef _W64 unsigned int UINT_PTR, *PUINT_PTR;

typedef UINT_PTR        SOCKET;

#define INVALID_SOCKET  (SOCKET)(~0)

 

(~0)的值为-1;

(SOCKET)(~0)的值为:十六进制0xFFFFFFFF(十进制4294967295)。



WSAGetLastError()

http://baike.baidu.com/link?url=SsTlzJ16os_qifhAfsEaQabL5X_AJqtvrs-HRizK_jX4T2_-Q9TwFD_tXuhuhlPU

#include "Communication.h" #include <iostream> CommunicationBase::CommunicationBase() : m_socket(INVALID_SOCKET), m_running(false), m_receiveThread(NULL), m_queueEvent(NULL) { InitializeCriticalSection(&m_queueCS); m_queueEvent = CreateEvent(NULL, FALSE, FALSE, NULL); } CommunicationBase::~CommunicationBase() { CloseSocket(); DeleteCriticalSection(&m_queueCS); if (m_queueEvent) CloseHandle(m_queueEvent); } void CommunicationBase::CloseSocket() { if (m_socket != INVALID_SOCKET) { m_running = false; // 关闭套接字会终止接收线程 shutdown(m_socket, SD_BOTH); closesocket(m_socket); m_socket = INVALID_SOCKET; if (m_receiveThread) { WaitForSingleObject(m_receiveThread, INFINITE); CloseHandle(m_receiveThread); m_receiveThread = NULL; } } } bool CommunicationBase::SendMessageTcp(const std::string& message) { if (m_socket == INVALID_SOCKET || !m_running) return false; const char* data = message.c_str(); int length = static_cast<int>(message.size()); int totalSent = 0; while (totalSent < length) { int sent = send(m_socket, data + totalSent, length - totalSent, 0); if (sent == SOCKET_ERROR) { std::cerr << "发送失败: " << WSAGetLastError() << std::endl; return false; } totalSent += sent; } return true; } //bool SendMessageTcp(SOCKET socket, const std::string& message) { // const char* data = message.data(); // int total = static_cast<int>(message.size()); // int sent = 0; // // while (sent < total && m_running) { // int bytes = send(socket, data + sent, total - sent, 0); // // if (bytes == SOCKET_ERROR) { // int error = WSAGetLastError(); // if (error == WSAEWOULDBLOCK) { // // 等待套接字可写 // fd_set writeSet; // FD_ZERO(&writeSet); // FD_SET(socket, &writeSet); // // timeval timeout{ 0, 10000 }; // 10ms超时 // if (select(0, NULL, &writeSet, NULL, &timeout) <= 0) { // continue; // 超时或错误 // } // } // else { // // 处理其他错误 // closesocket(socket); // return false; // } // } // else { // sent += bytes; // } // } // return sent == total; //} std::string CommunicationBase::ReceiveMessage(DWORD timeout_ms) { EnterCriticalSection(&m_queueCS); if (m_messageQueue.empty()) { LeaveCriticalSection(&m_queueCS); WaitForSingleObject(m_queueEvent, timeout_ms); EnterCriticalSection(&m_queueCS); } if (m_messageQueue.empty()) { LeaveCriticalSection(&m_queueCS); return ""; } std::string msg = m_messageQueue.front(); m_messageQueue.pop(); LeaveCriticalSection(&m_queueCS); return msg; } DWORD WINAPI CommunicationBase::ReceiveThreadProc(LPVOID lpParam) { CommunicationBase* pThis = reinterpret_cast<CommunicationBase*>(lpParam); char buffer[4096]; int bytesReceived; while (pThis->m_running) { bytesReceived = recv(pThis->m_socket, buffer, sizeof(buffer) - 1, 0); if (bytesReceived == SOCKET_ERROR) { int error = WSAGetLastError(); if (error == WSAEWOULDBLOCK) { Sleep(10); continue; } break; } if (bytesReceived <= 0) { break; } buffer[bytesReceived] = '\0'; std::string msg(buffer); EnterCriticalSection(&pThis->m_queueCS); pThis->m_messageQueue.push(msg); SetEvent(pThis->m_queueEvent); LeaveCriticalSection(&pThis->m_queueCS); } pThis->m_running = false; return 0; } Server::Server(int port) : m_port(port), m_acceptThread(NULL) { InitializeCriticalSection(&m_clientsCS); m_socket = INVALID_SOCKET; } Server::~Server() { Stop(); DeleteCriticalSection(&m_clientsCS); } bool Server::Start() { WSADATA wsaData; if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) { std::cerr << "WSAStartup失败" << std::endl; return false; } m_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if (m_socket == INVALID_SOCKET) { std::cerr << "创建套接字失败" << std::endl; WSACleanup(); return false; } sockaddr_in serverAddr; serverAddr.sin_family = AF_INET; serverAddr.sin_addr.s_addr = INADDR_ANY; serverAddr.sin_port = htons(m_port); if (bind(m_socket, (sockaddr*)& serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) { std::cerr << "绑定失败: " << WSAGetLastError() << std::endl; closesocket(m_socket); WSACleanup(); return false; } if (listen(m_socket, SOMAXCONN) == SOCKET_ERROR) { std::cerr << "监听失败" << std::endl; closesocket(m_socket); WSACleanup(); return false; } // 设置非阻塞模式 u_long mode = 1; ioctlsocket(m_socket, FIONBIO, &mode); m_running = true; // 启动接受客户端线程 m_acceptThread = CreateThread(NULL, 0, AcceptThreadProc, this, 0, NULL); if (m_acceptThread == NULL) { std::cerr << "创建接受线程失败" << std::endl; closesocket(m_socket); WSACleanup(); return false; } std::cout << "服务器已启动,监听端口: " << m_port << std::endl; return true; } void Server::Stop() { m_running = false; // 关闭所有客户端套接字 EnterCriticalSection(&m_clientsCS); for (size_t i = 0; i < m_clientSockets.size(); ++i) { if (m_clientSockets[i] != INVALID_SOCKET) { shutdown(m_clientSockets[i], SD_BOTH); closesocket(m_clientSockets[i]); } } m_clientSockets.clear(); LeaveCriticalSection(&m_clientsCS); CloseSocket(); if (m_acceptThread) { WaitForSingleObject(m_acceptThread, INFINITE); CloseHandle(m_acceptThread); m_acceptThread = NULL; } WSACleanup(); std::cout << "服务器已停止" << std::endl; } DWORD WINAPI Server::AcceptThreadProc(LPVOID lpParam) { Server* pServer = reinterpret_cast<Server*>(lpParam); pServer->AcceptClients(); return 0; } DWORD WINAPI Server::ClientThreadProc(LPVOID lpParam) { ClientThreadParam* param = reinterpret_cast<ClientThreadParam*>(lpParam); param->server->HandleClient(param->clientSocket); delete param; return 0; } void Server::AcceptClients() { while (m_running) { sockaddr_in clientAddr; int addrLen = sizeof(clientAddr); SOCKET clientSocket = accept(m_socket, (sockaddr*)& clientAddr, &addrLen); if (clientSocket == INVALID_SOCKET) { int error = WSAGetLastError(); if (error == WSAEWOULDBLOCK) { Sleep(100); continue; } break; } // 设置非阻塞模式a u_long mode = 1; ioctlsocket(clientSocket, FIONBIO, &mode); EnterCriticalSection(&m_clientsCS); m_clientSockets.push_back(clientSocket); LeaveCriticalSection(&m_clientsCS); char ipStr[INET_ADDRSTRLEN]; inet_ntop(AF_INET, &clientAddr.sin_addr, ipStr, INET_ADDRSTRLEN); std::cout << "新客户端连接: " << ipStr << ":" << ntohs(clientAddr.sin_port) << std::endl; // 创建线程参数 ClientThreadParam* param = new ClientThreadParam; param->server = this; param->clientSocket = clientSocket; // 创建客户端处理线程 HANDLE hThread = CreateThread( NULL, 0, ClientThreadProc, param, 0, NULL ); if (hThread == NULL) { std::cerr << "创建客户端线程失败: " << GetLastError() << std::endl; delete param; closesocket(clientSocket); } else { CloseHandle(hThread); // 立即关闭线程句柄,不保留 } } } void Server::HandleClient(SOCKET clientSocket) { char buffer[4096]; int bytesReceived; while (m_running) { bytesReceived = recv(clientSocket, buffer, sizeof(buffer) - 1, 0); if (bytesReceived == SOCKET_ERROR) { int error = WSAGetLastError(); if (error == WSAEWOULDBLOCK) { Sleep(10); continue; } break; } if (bytesReceived <= 0) { break; } buffer[bytesReceived] = '\0'; std::string msg(buffer); // 添加到消息队列 EnterCriticalSection(&m_queueCS); m_messageQueue.push(msg); SetEvent(m_queueEvent); LeaveCriticalSection(&m_queueCS); std::cout << "收到消息: " << msg << std::endl; // 广播给其他客户端 Broadcast(msg, clientSocket); } // 移除断开连接的客户端 EnterCriticalSection(&m_clientsCS); for (std::vector<SOCKET>::iterator it = m_clientSockets.begin(); it != m_clientSockets.end(); ++it) { if (*it == clientSocket) { closesocket(clientSocket); m_clientSockets.erase(it); break; } } LeaveCriticalSection(&m_clientsCS); std::cout << "客户端断开连接" << std::endl; } void Server::StartReceiver() { // 服务器使用每个客户端单独的线程处理接收 } void Server::Broadcast(const std::string& message, SOCKET excludeSocket) { EnterCriticalSection(&m_clientsCS); for (size_t i = 0; i < m_clientSockets.size(); ++i) { if (m_clientSockets[i] != excludeSocket && m_clientSockets[i] != INVALID_SOCKET) { send(m_clientSockets[i], message.c_str(), static_cast<int>(message.size()), 0); } } LeaveCriticalSection(&m_clientsCS); } Client::Client(const std::string& ip, int port) : m_serverIP(ip), m_port(port) { m_socket = INVALID_SOCKET; } Client::~Client() { Disconnect(); } bool Client::Connect() { WSADATA wsaData; if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) { std::cerr << "WSAStartup failed" << std::endl; return false; } m_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP); if (m_socket == INVALID_SOCKET) { std::cerr << "Socket creation failed" << std::endl; WSACleanup(); return false; } sockaddr_in serverAddr; serverAddr.sin_family = AF_INET; serverAddr.sin_port = htons(m_port); inet_pton(AF_INET, m_serverIP.c_str(), &serverAddr.sin_addr); if (connect(m_socket, (sockaddr*)& serverAddr, sizeof(serverAddr)) == SOCKET_ERROR) { std::cerr << "Connection failed: " << WSAGetLastError() << std::endl; closesocket(m_socket); WSACleanup(); return false; } // 设置非阻塞模式 u_long mode = 1; ioctlsocket(m_socket, FIONBIO, &mode); m_running = true; StartReceiver(); std::cout << "Connected to server: " << m_serverIP << ":" << m_port << std::endl; return true; } void Client::Disconnect() { m_running = false; CloseSocket(); WSACleanup(); std::cout << "Disconnected from server" << std::endl; } void Client::StartReceiver() { m_receiveThread = CreateThread(NULL, 0, ReceiveThreadProc, this, 0, NULL); if (m_receiveThread == NULL) { std::cerr << "Failed to create receive thread" << std::endl; m_running = false; } } // 明确的发送接口 bool Client::Send(const std::string& message) { if (m_socket == INVALID_SOCKET || !m_running) { return false; } return SendMessageTcp(message); } // 阻塞式接收 bool Client::Receive(std::string& outMessage, DWORD timeout_ms) { outMessage = ReceiveMessage(timeout_ms); return !outMessage.empty(); } // 非阻塞式接收 bool Client::TryReceive(std::string& outMessage) { EnterCriticalSection(&m_queueCS); if (m_messageQueue.empty()) { LeaveCriticalSection(&m_queueCS); return false; } outMessage = m_messageQueue.front(); m_messageQueue.pop(); LeaveCriticalSection(&m_queueCS); return true; } 仔细阅读代码
06-25
#include <stdio.h> #include <winsock2.h> #pragma comment(lib, "ws2_32.lib") #define PORT 8888 int main() { WSADATA wsa; SOCKET server_socket, client_socket; struct sockaddr_in server, client; int c; char message[] = "Hello from Windows"; // 初始化Winsock if (WSAStartup(MAKEWORD(2, 2), &wsa) != 0) { printf("WSAStartup失败. 错误代码: %d", WSAGetLastError()); return 1; } // 创建Socket if ((server_socket = socket(AF_INET, SOCK_STREAM, 0)) == INVALID_SOCKET) { printf("创建socket失败: %d", WSAGetLastError()); return 1; } // 配置服务器地址 server.sin_family = AF_INET; server.sin_addr.s_addr = INADDR_ANY; server.sin_port = htons(PORT); // 绑定 if (bind(server_socket, (struct sockaddr*)&server, sizeof(server)) == SOCKET_ERROR) { printf("绑定失败: %d", WSAGetLastError()); closesocket(server_socket); return 1; } // 监听 listen(server_socket, 3); printf("等待连接...\n"); // 接受客户端连接 c = sizeof(struct sockaddr_in); client_socket = accept(server_socket, (struct sockaddr*)&client, &c); if (client_socket == INVALID_SOCKET) { printf("接受连接失败: %d", WSAGetLastError()); return 1; } // 通信循环 while (1) { char client_message[2000]; int recv_size; // 接收数据 if ((recv_size = recv(client_socket, client_message, 2000, 0)) == SOCKET_ERROR) { puts("接收失败"); break; } client_message[recv_size] = '\0'; printf("收到消息: %s\n", client_message); // 发送回复 send(client_socket, message, strlen(message), 0); } closesocket(server_socket); WSACleanup(); return 0; }改进这个程序使他不仅能接受客户端的消息,还能向客户端发消息
03-08
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