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QSocketDevice(3qt)					    QSocketDevice(3qt)

NAME
       QSocketDevice - Platform-independent low-level socket API

SYNOPSIS
       #include <qsocketdevice.h>

       Inherits QIODevice.

   Public Members
       enum Type { Stream, Datagram }
       enum Protocol { IPv4, IPv6, Unknown }
       QSocketDevice ( Type type = Stream )
       QSocketDevice ( Type type, Protocol protocol, int dummy )
       QSocketDevice ( int socket, Type type )
       virtual ~QSocketDevice ()
       bool isValid () const
       Type type () const
       Protocol protocol () const
       int socket () const
       virtual void setSocket ( int socket, Type type )
       bool blocking () const
       virtual void setBlocking ( bool enable )
       bool addressReusable () const
       virtual void setAddressReusable ( bool enable )
       int receiveBufferSize () const
       virtual void setReceiveBufferSize ( uint size )
       int sendBufferSize () const
       virtual void setSendBufferSize ( uint size )
       virtual bool connect ( const QHostAddress & addr, Q_UINT16 port )
       virtual bool bind ( const QHostAddress & address, Q_UINT16 port )
       virtual bool listen ( int backlog )
       virtual int accept ()
       Q_LONG bytesAvailable () const
       Q_LONG waitForMore ( int msecs, bool * timeout = 0 ) const
       virtual Q_LONG readBlock ( char * data, Q_ULONG maxlen )
       virtual Q_LONG writeBlock ( const char * data, Q_ULONG len )
       virtual Q_LONG writeBlock ( const char * data, Q_ULONG len, const
	   QHostAddress & host, Q_UINT16 port )
       Q_UINT16 port () const
       Q_UINT16 peerPort () const
       QHostAddress address () const
       QHostAddress peerAddress () const
       enum Error { NoError, AlreadyBound, Inaccessible, NoResources,
	   InternalError, Bug = InternalError, Impossible, NoFiles,
	   ConnectionRefused, NetworkFailure, UnknownError }
       Error error () const

   Protected Members
       void setError ( Error err )

DESCRIPTION
       The QSocketDevice class provides a platform-independent low-level
       socket API.

       This class provides a low level API for working with sockets. Users of
       this class are assumed to have networking experience. For most users
       the QSocket class provides a much easier and high level alternative,
       but certain things (like UDP) can't be done with QSocket and if you
       need a platform-independent API for those, QSocketDevice is the right
       choice.

       The essential purpose of the class is to provide a QIODevice that works
       on sockets, wrapped in a platform-independent API.

       When calling connect() or bind(), QSocketDevice detects the protocol
       family (IPv4, IPv6) automatically. Passing the protocol family to
       QSocketDevice's constructor or to setSocket() forces creation of a
       socket device of a specific protocol. If not set, the protocol will be
       detected at the first call to connect() or bind().

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

   Member Type Documentation
QSocketDevice::Error
       This enum type describes the error states of QSocketDevice.

       QSocketDevice::NoError - No error has occurred.

       QSocketDevice::AlreadyBound - The device is already bound, according to
       bind().

       QSocketDevice::Inaccessible - The operating system or firewall
       prohibited the action.

       QSocketDevice::NoResources - The operating system ran out of a
       resource.

       QSocketDevice::InternalError - An internal error occurred in
       QSocketDevice.

       QSocketDevice::Impossible - An attempt was made to do something which
       makes no sense. For example:

		  ::close( sd->socket() );
		  sd->writeBlock( someData, 42 );
	      The libc ::close() closes the socket, but QSocketDevice is not
	      aware of this. So when you call writeBlock(), the impossible
	      happens.

       QSocketDevice::NoFiles - The operating system will not let
       QSocketDevice open another file.

       QSocketDevice::ConnectionRefused - A connection attempt was rejected by
       the peer.

       QSocketDevice::NetworkFailure - There is a network failure.

       QSocketDevice::UnknownError - The operating system did something
       unexpected.

QSocketDevice::Protocol
       This enum type describes the protocol family of the socket. Possible
       values are:

       QSocketDevice::IPv4 - The socket is an IPv4 socket.

       QSocketDevice::IPv6 - The socket is an IPv6 socket.

       QSocketDevice::Unknown - The protocol family of the socket is not
       known. This can happen if you use QSocketDevice with an already
       existing socket; it tries to determine the protocol family, but this
       can fail if the protocol family is not known to QSocketDevice.

       See also protocol() and setSocket().

QSocketDevice::Type
       This enum type describes the type of the socket:

       QSocketDevice::Stream - a stream socket (TCP, usually)

       QSocketDevice::Datagram - a datagram socket (UDP, usually)

MEMBER FUNCTION DOCUMENTATION
QSocketDevice::QSocketDevice ( Type type = Stream )
       Creates a QSocketDevice object for a stream or datagram socket.

       The type argument must be either QSocketDevice::Stream for a reliable,
       connection-oriented TCP socket, or QSocketDevice::Datagram for an
       unreliable UDP socket.

       The socket is created as an IPv4 socket.

       See also blocking() and protocol().

QSocketDevice::QSocketDevice ( Type type, Protocol protocol, int dummy )
       Creates a QSocketDevice object for a stream or datagram socket.

       The type argument must be either QSocketDevice::Stream for a reliable,
       connection-oriented TCP socket, or QSocketDevice::Datagram for an
       unreliable UDP socket.

       The protocol indicates whether the socket should be of type IPv4 or
       IPv6. Passing Unknown is not meaningful in this context and you should
       avoid using (it creates an IPv4 socket, but your code is not easily
       readable).

       The argument dummy is necessary for compatibility with some compilers.

       See also blocking() and protocol().

QSocketDevice::QSocketDevice ( int socket, Type type )
       Creates a QSocketDevice object for the existing socket socket.

       The type argument must match the actual socket type; use
       QSocketDevice::Stream for a reliable, connection-oriented TCP socket,
       or QSocketDevice::Datagram for an unreliable, connectionless UDP
       socket.

QSocketDevice::~QSocketDevice () [virtual]
       Destroys the socket device and closes the socket if it is open.

int QSocketDevice::accept () [virtual]
       Extracts the first connection from the queue of pending connections for
       this socket and returns a new socket identifier. Returns -1 if the
       operation failed.

       See also bind() and listen().

QHostAddress QSocketDevice::address () const
       Returns the address of this socket device. This may be 0.0.0.0 for a
       while, but is set to something sensible as soon as a sensible value is
       available.

bool QSocketDevice::addressReusable () const
       Returns TRUE if the address of this socket can be used by other sockets
       at the same time, and FALSE if this socket claims exclusive ownership.

       See also setAddressReusable().

bool QSocketDevice::bind ( const QHostAddress & address, Q_UINT16 port )
       [virtual]
       Assigns a name to an unnamed socket. The name is the host address
       address and the port number port. If the operation succeeds, bind()
       returns TRUE; otherwise it returns FALSE without changing what port()
       and address() return.

       bind() is used by servers for setting up incoming connections. Call
       bind() before listen().

bool QSocketDevice::blocking () const
       Returns TRUE if the socket is valid and in blocking mode; otherwise
       returns FALSE.

       Note that this function does not set error().

       Warning: On Windows, this function always returns TRUE since the
       ioctlsocket() function is broken.

       See also setBlocking() and isValid().

Q_LONG QSocketDevice::bytesAvailable () const
       Returns the number of bytes available for reading, or -1 if an error
       occurred.

       Warning: On Microsoft Windows, we use the ioctlsocket() function to
       determine the number of bytes queued on the socket. According to
       Microsoft (KB Q125486), ioctlsocket() sometimes returns an incorrect
       number. The only safe way to determine the amount of data on the socket
       is to read it using readBlock(). QSocket has workarounds to deal with
       this problem.

bool QSocketDevice::connect ( const QHostAddress & addr, Q_UINT16 port )
       [virtual]
       Connects to the IP address and port specified by addr and port. Returns
       TRUE if it establishes a connection; otherwise returns FALSE. If it
       returns FALSE, error() explains why.

       Note that error() commonly returns NoError for non-blocking sockets;
       this just means that you can call connect() again in a little while and
       it'll probably succeed.

Error QSocketDevice::error () const
       Returns the first error seen.

bool QSocketDevice::isValid () const
       Returns TRUE if this is a valid socket; otherwise returns FALSE.

       See also socket().

bool QSocketDevice::listen ( int backlog ) [virtual]
       Specifies how many pending connections a server socket can have.
       Returns TRUE if the operation was successful; otherwise returns FALSE.
       A backlog value of 50 is quite common.

       The listen() call only applies to sockets where type() is Stream, i.e.
       not to Datagram sockets. listen() must not be called before bind() or
       after accept().

       See also bind() and accept().

QHostAddress QSocketDevice::peerAddress () const
       Returns the address of the port this socket device is connected to.
       This may be 0.0.0.0 for a while, but is set to something sensible as
       soon as a sensible value is available.

       Note that for Datagram sockets, this is the source port of the last
       packet received.

Q_UINT16 QSocketDevice::peerPort () const
       Returns the port number of the port this socket device is connected to.
       This may be 0 for a while, but is set to something sensible as soon as
       a sensible value is available.

       Note that for Datagram sockets, this is the source port of the last
       packet received, and that it is in native byte order.

Q_UINT16 QSocketDevice::port () const
       Returns the port number of this socket device. This may be 0 for a
       while, but is set to something sensible as soon as a sensible value is
       available.

       Note that Qt always uses native byte order, i.e. 67 is 67 in Qt; there
       is no need to call htons().

Protocol QSocketDevice::protocol () const
       Returns the socket's protocol family, which is one of Unknown, IPv4, or
       IPv6.

       QSocketDevice either creates a socket with a well known protocol family
       or it uses an already existing socket. In the first case, this function
       returns the protocol family it was constructed with. In the second
       case, it tries to determine the protocol family of the socket; if this
       fails, it returns Unknown.

       See also Protocol and setSocket().

Q_LONG QSocketDevice::readBlock ( char * data, Q_ULONG maxlen ) [virtual]
       Reads maxlen bytes from the socket into data and returns the number of
       bytes read. Returns -1 if an error occurred. Returning 0 is not an
       error. For Stream sockets, 0 is returned when the remote host closes
       the connection. For Datagram sockets, 0 is a valid datagram size.

       Reimplemented from QIODevice.

int QSocketDevice::receiveBufferSize () const
       Returns the size of the operating system receive buffer.

       See also setReceiveBufferSize().

int QSocketDevice::sendBufferSize () const
       Returns the size of the operating system send buffer.

       See also setSendBufferSize().

void QSocketDevice::setAddressReusable ( bool enable ) [virtual]
       Sets the address of this socket to be usable by other sockets too if
       enable is TRUE, and to be used exclusively by this socket if enable is
       FALSE.

       When a socket is reusable, other sockets can use the same port number
       (and IP address), which is generally useful. Of course other sockets
       cannot use the same (address,port,peer-address,peer-port) 4-tuple as
       this socket, so there is no risk of confusing the two TCP connections.

       See also addressReusable().

void QSocketDevice::setBlocking ( bool enable ) [virtual]
       Makes the socket blocking if enable is TRUE or nonblocking if enable is
       FALSE.

       Sockets are blocking by default, but we recommend using nonblocking
       socket operations, especially for GUI programs that need to be
       responsive.

       Warning: On Windows, this function should be used with care since
       whenever you use a QSocketNotifier on Windows, the socket is
       immediately made nonblocking.

       See also blocking() and isValid().

void QSocketDevice::setError ( Error err ) [protected]
       Allows subclasses to set the error state to err.

void QSocketDevice::setReceiveBufferSize ( uint size ) [virtual]
       Sets the size of the operating system receive buffer to size.

       The operating system receive buffer size effectively limits two things:
       how much data can be in transit at any one moment, and how much data
       can be received in one iteration of the main event loop.

       The default is operating system-dependent. A socket that receives large
       amounts of data is probably best with a buffer size of 49152.

void QSocketDevice::setSendBufferSize ( uint size ) [virtual]
       Sets the size of the operating system send buffer to size.

       The operating system send buffer size effectively limits how much data
       can be in transit at any one moment.

       The default is operating system-dependent. A socket that sends large
       amounts of data is probably best with a buffer size of 49152.

void QSocketDevice::setSocket ( int socket, Type type ) [virtual]
       Sets the socket device to operate on the existing socket socket.

       The type argument must match the actual socket type; use
       QSocketDevice::Stream for a reliable, connection-oriented TCP socket,
       or QSocketDevice::Datagram for an unreliable, connectionless UDP
       socket.

       Any existing socket is closed.

       See also isValid() and close().

int QSocketDevice::socket () const
       Returns the socket number, or -1 if it is an invalid socket.

       See also isValid() and type().

Type QSocketDevice::type () const
       Returns the socket type which is either QSocketDevice::Stream or
       QSocketDevice::Datagram.

       See also socket().

Q_LONG QSocketDevice::waitForMore ( int msecs, bool * timeout = 0 ) const
       Wait up to msecs milliseconds for more data to be available. If msecs
       is -1 the call will block indefinitely.

       Returns the number of bytes available for reading, or -1 if an error
       occurred.

       If timeout is non-null and no error occurred (i.e. it does not return
       -1): this function sets *timeout to TRUE, if the reason for returning
       was that the timeout was reached; otherwise it sets *timeout to FALSE.
       This is useful to find out if the peer closed the connection.

       Warning: This is a blocking call and should be avoided in event driven
       applications.

       See also bytesAvailable().

Q_LONG QSocketDevice::writeBlock ( const char * data, Q_ULONG len ) [virtual]
       Writes len bytes to the socket from data and returns the number of
       bytes written. Returns -1 if an error occurred.

       This is used for QSocketDevice::Stream sockets.

       Reimplemented from QIODevice.

Q_LONG QSocketDevice::writeBlock ( const char * data, Q_ULONG len, const
       QHostAddress & host, Q_UINT16 port ) [virtual]
       This is an overloaded member function, provided for convenience. It
       behaves essentially like the above function.

       Writes len bytes to the socket from data and returns the number of
       bytes written. Returns -1 if an error occurred.

       This is used for QSocketDevice::Datagram sockets. You must specify the
       host and port of the destination of the data.

SEE ALSO
       http://doc.trolltech.com/qsocketdevice.html
       http://www.trolltech.com/faq/tech.html

COPYRIGHT
       Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com.  See the
       license file included in the distribution for a complete license
       statement.

AUTHOR
       Generated automatically from the source code.

BUGS
       If you find a bug in Qt, please report it as described in
       http://doc.trolltech.com/bughowto.html.	Good bug reports help us to
       help you. Thank you.

       The definitive Qt documentation is provided in HTML format; it is
       located at $QTDIR/doc/html and can be read using Qt Assistant or with a
       web browser. This man page is provided as a convenience for those users
       who prefer man pages, although this format is not officially supported
       by Trolltech.

       If you find errors in this manual page, please report them to qt-
       bugs@trolltech.com.  Please include the name of the manual page
       (qsocketdevice.3qt) and the Qt version (3.3.8).

Trolltech AS			2 February 2007		    QSocketDevice(3qt)
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