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# QServerSocket Class Reference
[network module]

The QServerSocket class provides a TCP-based server. More...

`#include <qserversocket.h>`

Inherits QObject.

List of all member functions.

## Public Members

- QServerSocket ( Q_UINT16 port, int backlog = 1, QObject * parent = 0, const char * name = 0 )
- QServerSocket ( const QHostAddress & address, Q_UINT16 port, int backlog = 1, QObject * parent = 0, const char * name = 0 )
- QServerSocket ( QObject * parent = 0, const char * name = 0 )
- virtual ~QServerSocket ()
- bool ok () const
- Q_UINT16 port () const
- int socket () const
- virtual void setSocket ( int socket )
- QHostAddress address () const
- virtual void newConnection ( int socket ) = 0

## Protected Members

- QSocketDevice * socketDevice ()

## Detailed Description

The QServerSocket class provides a TCP-based server.

This class is a convenience class for accepting incoming TCP connections. You can specify the port or have QServerSocket pick one, and listen on just one address or on all the machine's addresses.

Using the API is very simple: subclass QServerSocket, call the constructor of your choice, and implement newConnection() to handle new incoming connections. There is nothing more to do.

(Note that due to lack of support in the underlying APIs, QServerSocket cannot accept or reject connections conditionally.)

See also QSocket, QSocketDevice, QHostAddress, QSocketNotifier and Input/Output and Networking.

## Member Function Documentation

### QServerSocket::QServerSocket ( Q_UINT16 port, int backlog = 1, QObject * parent = 0, const char * name = 0 )

Creates a server socket object, that will serve the given port on all the addresses of this host. If port is 0, QServerSocket will pick a suitable port in a system-dependent manner. Use backlog to specify how many pending connections the server can have.

The parent and name arguments are passed on to the QObject constructor.

Warning: On Tru64 Unix systems a value of 0 for backlog means that you don't accept any connections at all; you should specify a value larger than 0.

### QServerSocket::QServerSocket ( const QHostAddress & address, Q_UINT16 port, int backlog = 1, QObject * parent = 0, const char * name = 0 )

Creates a server socket object, that will serve the given port only on the given address. Use backlog to specify how many pending connections the server can have.

The parent and name arguments are passed on to the QObject constructor.

Warning: On Tru64 Unix systems a value of 0 for backlog means that you don't accept any connections at all; you should specify a value larger than 0.

### QServerSocket::QServerSocket ( QObject * parent = 0, const char * name = 0 )

Construct an empty server socket.

This constructor, in combination with setSocket(), allows us to use the QServerSocket class as a wrapper for other socket types (e.g. Unix Domain Sockets under Unix).

The parent and name arguments are passed on to the QObject constructor.

See also setSocket().

### QServerSocket::~QServerSocket ()`[virtual]`

Destroys the socket.

This causes any backlogged connections (connections that have reached the host, but not yet been completely set up by calling QSocketDevice::accept()) to be severed.

Existing connections continue to exist; this only affects the acceptance of new connections.

### QHostAddress QServerSocket::address () const

Returns the address on which this object listens, or 0.0.0.0 if this object listens on more than one address. ok() must be TRUE before calling this function.

See also port() and QSocketDevice::address().

### void QServerSocket::newConnection ( int socket )`[pure virtual]`

This pure virtual function is responsible for setting up a new incoming connection. socket is the fd (file descriptor) for the newly accepted connection.

### bool QServerSocket::ok () const

Returns TRUE if the construction succeeded; otherwise returns FALSE.

### Q_UINT16 QServerSocket::port () const

Returns the port number on which this server socket listens. This is always non-zero; if you specify 0 in the constructor, QServerSocket will pick a non-zero port itself. ok() must be TRUE before calling this function.

See also address() and QSocketDevice::port().

Example: network/httpd/httpd.cpp.

### void QServerSocket::setSocket ( int socket )`[virtual]`

Sets the socket to use socket. bind() and listen() should already have been called for socket.

This allows us to use the QServerSocket class as a wrapper for other socket types (e.g. Unix Domain Sockets).

### int QServerSocket::socket () const

Returns the operating system socket.

### QSocketDevice * QServerSocket::socketDevice ()`[protected]`

Returns a pointer to the internal socket device. The returned pointer is 0 if there is no connection or pending connection.

There is normally no need to manipulate the socket device directly since this class does all the necessary setup for most client or server socket applications.

This file is part of the Qt toolkit. Copyright © 1995-2002 Trolltech. All Rights Reserved.