Windows网络编程使用winsock。Winsock是一个基于Socket模型的API，在Windows系统中广泛使用。
使用Winsock进行网络编程需要包含头文件Winsock2.h，需要使用库ws2_32.lib，包含方法：可以使用语句来告诉编译器连接该库
#pragma comment(lib, “ws2_32.lib”);
如果使用VS，可以通过“项目” --> “XX属性”--> “连接器”-->“输入”--> “附加依赖项”添加ws2_32.lib。 （XX为当前工程名）
● 面向连接的C/S程序工程流程图
使用Winsock API编制的网络应用程序中，在调用任何一个Winsock函数之前都必须检查协议栈安装情况，使用函数WSAStartup()完成操作。
● 一个服务端的例子
View Code 
void server::startServer() { WORD wVersionRequested; WSADATA wsaData; wVersionRequested=MAKEWORD(2,2); if(WSAStartup(wVersionRequested,&wsaData)!=0) { //Winsock初始化错误 msgBox.exec(); return; } if(wsaData.wVersion!=wVersionRequested) { //Winsock版本不匹配 WSACleanup(); return; } if ((m_sk = socket(AF_INET, SOCK_STREAM, 0)) == SOCKET_ERROR) { WSACleanup(); return; } bool ok; unsigned short port = ui.portLineEdit->text().toInt(&ok, 10); if (ok == false) { //端口输入错误 closesocket(m_sk); m_sk = -1; WSACleanup(); return; } sockaddr_in addr; addr.sin_family = AF_INET; //使用互联网际协议，即IP协议 addr.sin_port = htons(port); addr.sin_addr.S_un.S_addr = htonl(INADDR_ANY); if (bind(m_sk, (sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR) { //绑定端口失败 closesocket(m_sk); m_sk = -1; WSACleanup(); return; } if (listen(m_sk, 10) == SOCKET_ERROR) { //监听端口失败 closesocket(m_sk); m_sk = -1; WSACleanup(); return; } updateMsgRecs(tr("等待连接...")); //创建线程去等待连接 HANDLE h = CreateThread(NULL, 0, &server::acceptProc, (LPVOID)this, 0, 0); if (h == NULL) { closesocket(m_sk); m_sk = -1; WSACleanup(); return; } CloseHandle(h); }
● 监听线程函数
View Code
DWORD WINAPI server::acceptProc(LPVOID lpParamter) { /*server *p_server = (server *)lpParamter; sockaddr_in client_addr; int len = sizeof(client_addr); char msgBuff[256]; int sk; while (1) { if ((sk = ::accept(p_server->sk(), (sockaddr*)&client_addr, &len) )== SOCKET_ERROR) { emit p_server->haveNewMsg(QObject::tr("accept 出错")); break; } sprintf(msgBuff, "新连接来自%s", inet_ntoa(client_addr.sin_addr)); emit p_server->haveNewMsg(msgBuff); emit p_server->newClient(inet_ntoa(client_addr.sin_addr), sk); }*/ server *p_server = (server *)lpParamter; int client[FD_SETSIZE]; fd_set allset, rset; sockaddr_in client_addr; int len; int clientfd; int sockfd; int i; for (i=0; i<FD_SETSIZE; i++) client[i] = -1; FD_ZERO(&allset); int listenfd = p_server->sk(); FD_SET(listenfd, &allset); int nready; int maxfd = listenfd; int maxi = -1; char buff[MAX_LEN+1]; while (1) { rset = allset; nready = select(maxfd+1, &rset, NULL, NULL, NULL); if (FD_ISSET(listenfd, &rset)) //new connection { len = sizeof(client_addr); if ( (clientfd = ::accept(p_server->sk(), (sockaddr*)&client_addr, &len)) == SOCKET_ERROR) { emit p_server->haveNewMsg(QObject::tr("accept 出错")); break; } //找出client数组中第一个为-1的单元存放已经连接的socket for (i=0; i<FD_SETSIZE; i++) { if (client[i] <0) { client[i] = clientfd; break; } } if (i == FD_SETSIZE) { emit p_server->haveNewMsg(QObject::tr("error: too many clients!")); break; } //sprintf(buff, "新连接来自%s", inet_ntoa(client_addr.sin_addr)); //emit p_server->haveNewMsg(buff); emit p_server->newClient(inet_ntoa(client_addr.sin_addr), clientfd); FD_SET(clientfd, &allset); if (clientfd > maxfd) maxfd = clientfd; if (i>maxi) maxi = i; if (--nready <= 0) continue; } for (i=0; i<=maxi; i++) { if ( (sockfd = client[i]) < 0) continue; if (FD_ISSET(sockfd, &rset)) { int n; //客户端已经关闭连接 if ( (n = recv(sockfd, buff, MAX_LEN, 0 )) <= 0) { closesocket(sockfd); FD_CLR(sockfd, &allset); client[i] = -1; emit p_server->haveNewMsg(QObject::tr("client closed")); emit p_server->sClientClose(sockfd); } else //收到数据 { buff[n] = 0; emit p_server->haveNewMsg( buff, sockfd); if (--nready <= 0) break; } } } //for (i=0; i<=maxi; i++) } return 0; }
● 一个客户端的例子
View Code
void client::connectServer() { WORD wVersionRequested; WSADATA wsaData; wVersionRequested=MAKEWORD(2,2); if(WSAStartup(wVersionRequested,&wsaData)!=0) { //Winsock初始化错误 QMessageBox msgBox(QMessageBox::Warning, tr("错误"), tr("Winsock初始化错误"), QMessageBox::Ok, 0); msgBox.exec(); return; } if(wsaData.wVersion!=wVersionRequested) { //Winsock版本不匹配 QMessageBox msgBox(QMessageBox::Warning, tr("错误"), tr("Winsock版本不匹配"), QMessageBox::Ok, 0); msgBox.exec(); WSACleanup(); return; } if ((m_sk = socket(AF_INET, SOCK_STREAM, 0)) == SOCKET_ERROR) { QMessageBox msgBox(QMessageBox::Warning, tr("错误"), tr("创建socket失败"), QMessageBox::Ok, 0); msgBox.exec(); WSACleanup(); return; } sockaddr_in addr; addr.sin_family = AF_INET; bool ok; unsigned short port = ui.portLineEdit->text().toInt(&ok, 10); if (ok == false) { QMessageBox msgBox(QMessageBox::Warning, tr("错误"), tr("端口输入错误"), QMessageBox::Ok, 0); msgBox.exec(); closesocket(m_sk); m_sk = -1; WSACleanup(); return; } addr.sin_port = htons(port); addr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1"); if (0 == ::connect(m_sk, (sockaddr *)&addr, sizeof(addr))) { updateMsgRecs(tr("连接成功...")); HANDLE h = CreateThread(NULL, 0, &client::recvProc, (LPVOID)this, 0, 0); CloseHandle(h); } else { QMessageBox msgBox(QMessageBox::Warning, tr("错误"), tr("连接出错"), QMessageBox::Ok, 0); msgBox.exec(); closesocket(m_sk); m_sk = -1; WSACleanup(); } }
● winsock APIs
网络连接函数
socket 创建套接字
bind 绑定本机端口
connect 建立连接
listen 监听端口
accept 接受连接
recv, recvfrom 数据接收
send, sendto 数据发送
close, shutdown 关闭套接字
转换函数
inet_addr() 点分十进制数表示的IP地址转换为网络字节序的IP地址
inet_ntoa() 网络字节序的IP地址转换为点分十进制数表示的IP地址
字节顺序转换函数
htonl 4字节主机字节序转换为网络字节序
ntohl 4字节网络字节序转换为主机字节序
htons 2字节主机字节序转换为网络字节序
ntohs 2字节网络字节序转换为主机字节序
网络信息检索函数
gethostname 获得主机名
getpeername 获得与套接口相连的远程协议地址
getsockname 获得套接口本地协议地址
gethostbyname 根据主机名取得主机信息
gethostbyaddr 根据主机地址取得主机信息
getprotobyname 根据协议名取得主机协议信息
getprotobynumber 根据协议号取得主机协议信息
getservbyname 根据服务名取得相关服务信息
getservbyport 根据端口号取得相关服务信息
getsockopt/setsockopt 获取/设置一个套接口选项
ioctlsocket 设置套接口的工作方式
