初学QT的TCP编程，有几点不明白。。
我是完全复制书上的程序的，虽然能运行成功了，但是代码中有几个地方不明白。。求求解。。
我不知道该怎么表达我想问的问题，只好把所有的程序粘贴出来，然后加些注释。。。
程序如下：
#ifndef SERVER_H#define SERVER_H#include <QtNetwork>#include "tcpclientsocket.h"class Server : public QTcpServer{ Q_OBJECTpublic: Server(QObject *parent = 0,int port=0); QList<TcpClientSocket*> tcpClientSocketList; [color=#FF0000] //这个尖括号代表什么意思？？[/color]signals: void updateServer(QString,int);public slots: void updateClients(QString,int); void slotDisconnected(int);protected: void incomingConnection(int socketDescriptor);};#endif#include "server.h"Server::Server(QObject *parent,int port) :QTcpServer(parent){ listen(QHostAddress::Any,port);}void Server::incomingConnection(int socketDescriptor){ TcpClientSocket *tcpClientSocket = new TcpClientSocket(this); connect(tcpClientSocket,SIGNAL(updateClients(QString,int)),this,SLOT(updateClients(QString,int))); [color=#FF0000]//上面的那个为什么信号和槽是一样的？？[/color] connect(tcpClientSocket,SIGNAL(disconnected(int)) ,this,SLOT(slotDisconnected(int))); tcpClientSocket->setSocketDescriptor(socketDescriptor); tcpClientSocketList.append(tcpClientSocket);}void Server::updateClients(QString msg, int length){ emit updateServer(msg,length);[color=#FF0000]//没有函数定义，那它怎么成为信号的？？[/color] for(int i = 0;i < tcpClientSocketList.count();i++) { QTcpSocket *item = tcpClientSocketList.at(i); if(item->write(msg.toLatin1(),length) != length)[color=#FF0000]//这句有什么用，我觉得没啥用好像多余的[/color] { [color=#FF0000]//直接item->write(msg.toLatin1(),length)不就行了吗？？[/color] continue; } }}void Server::slotDisconnected(int descriptor){ for(int i = 0;i < tcpClientSocketList.count();i++) { QTcpSocket *item = tcpClientSocketList.at(i); if(item->socketDescriptor() == descriptor) { tcpClientSocketList.removeAt(i); continue; } }}#include "tcpserver.h"TcpClientSocket::TcpClientSocket(QObject *parent){ connect(this,SIGNAL(readyRead()) ,this,SLOT(dataReceived())); connect(this,SIGNAL(disconnected()),this,SLOT(slotDisconnected()));}TcpClientSocket::~TcpClientSocket(){}void TcpClientSocket::dataReceived(){ while(bytesAvailable() > 0) { char buf[1024]; int length = bytesAvailable(); read(buf,length); QString msg = buf;[color=#FF0000]//这两条有什么用？？都没有执行的函数的？是不是只是提醒的作用而已？？[/color] emit updateClients(msg,length); }}void TcpClientSocket::slotDisconnected(){ emit disconnected(this->socketDescriptor());[color=#FF0000]//这条同上~~不明白~[/color]}#ifndef TCPSERVER_H#define TCPSERVER_H#include <QtGui>#include <QtNetWork>#include "server.h"class TcpServer : public QDialog{ Q_OBJECTpublic: TcpServer(QWidget *parent = 0,Qt::WindowFlags f = 0); ~TcpServer();public: QListWidget *ListWidgetContent; QLabel *LabelPort; QLineEdit *LineEditPort; QPushButton *pushButtonCreate; int port; Server *server;public slots: void slotCreateServer(); void updateServer(QString,int);};#endif // TCPSERVER_H
#include "tcpserver.h"TcpServer::TcpServer(QWidget *parent,Qt::WindowFlags f) : QDialog(parent,f){ setWindowTitle(tr("TCP Server")); QVBoxLayout *vbMain = new QVBoxLayout( this ); ListWidgetContent = new QListWidget( this); vbMain->addWidget( ListWidgetContent ); QHBoxLayout *hb = new QHBoxLayout( ); LabelPort = new QLabel( this ); LabelPort->setText(tr("Port:")); hb->addWidget( LabelPort ); LineEditPort = new QLineEdit(this); hb->addWidget( LineEditPort ); vbMain->addLayout(hb); pushButtonCreate = new QPushButton( this); pushButtonCreate->setText( tr( "Create" ) ); vbMain->addWidget( pushButtonCreate ); connect(pushButtonCreate,SIGNAL(clicked()),this,SLOT(slotCreateServer())); port = 8010; LineEditPort->setText(QString::number(port));}TcpServer::~TcpServer(){}void TcpServer::slotCreateServer(){ server = new Server(this,port); connect(server,SIGNAL(updateServer(QString,int)),SLOT(updateServer(QString,int))); [color=#FF0000]//上面信号为什么和槽的都是一样的？？这样代表什么意思？？[/color] pushButtonCreate->setEnabled(false);}void TcpServer::updateServer(QString msg, int length){ ListWidgetContent->addItem(msg.left(length));}