qsocketdevice.3qt

qt专门用于嵌入式的图形开发GUI

.PP
The \fItype\fR argument must be either QSocketDevice::Stream for a reliable, connection-oriented TCP socket, or QSocketDevice::Datagram for an unreliable UDP socket.
.PP
The socket is created as an IPv4 socket.
.PP
See also blocking() and protocol().
.SH "QSocketDevice::QSocketDevice ( Type type, Protocol protocol, int dummy )"
Creates a QSocketDevice object for a stream or datagram socket.
.PP
The \fItype\fR argument must be either QSocketDevice::Stream for a reliable, connection-oriented TCP socket, or QSocketDevice::Datagram for an unreliable UDP socket.
.PP
The \fIprotocol\fR 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).
.PP
The argument \fIdummy\fR is necessary for compatibility with some compilers.
.PP
See also blocking() and protocol().
.SH "QSocketDevice::QSocketDevice ( int socket, Type type )"
Creates a QSocketDevice object for the existing socket \fIsocket\fR.
.PP
The \fItype\fR 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.
.SH "QSocketDevice::~QSocketDevice ()\fC [virtual]\fR"
Destroys the socket device and closes the socket if it is open.
.SH "int QSocketDevice::accept ()\fC [virtual]\fR"
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.
.PP
See also bind() and listen().
.SH "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.
.SH "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.
.PP
See also setAddressReusable().
.SH "bool QSocketDevice::bind ( const QHostAddress & address, Q_UINT16 port )\fC [virtual]\fR"
Assigns a name to an unnamed socket. The name is the host address \fIaddress\fR and the port number \fIport\fR. If the operation succeeds, bind() returns TRUE; otherwise it returns FALSE without changing what port() and address() return.
.PP
bind() is used by servers for setting up incoming connections. Call bind() before listen().
.SH "bool QSocketDevice::blocking () const"
Returns TRUE if the socket is valid and in blocking mode; otherwise returns FALSE.
.PP
Note that this function does not set error().
.PP
\fBWarning:\fR On Windows, this function always returns TRUE since the ioctlsocket() function is broken.
.PP
See also setBlocking() and isValid().
.SH "Q_LONG QSocketDevice::bytesAvailable () const"
Returns the number of bytes available for reading, or -1 if an error occurred.
.PP
\fBWarning:\fR 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.
.SH "bool QSocketDevice::connect ( const QHostAddress & addr, Q_UINT16 port )\fC [virtual]\fR"
Connects to the IP address and port specified by \fIaddr\fR and \fIport\fR. Returns TRUE if it establishes a connection; otherwise returns FALSE. If it returns FALSE, error() explains why.
.PP
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.
.SH "Error QSocketDevice::error () const"
Returns the first error seen.
.SH "bool QSocketDevice::isValid () const"
Returns TRUE if this is a valid socket; otherwise returns FALSE.
.PP
See also socket().
.SH "bool QSocketDevice::listen ( int backlog )\fC [virtual]\fR"
Specifies how many pending connections a server socket can have. Returns TRUE if the operation was successful; otherwise returns FALSE. A \fIbacklog\fR value of 50 is quite common.
.PP
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().
.PP
See also bind() and accept().
.SH "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.
.PP
Note that for Datagram sockets, this is the source port of the last packet received.
.SH "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.
.PP
Note that for Datagram sockets, this is the source port of the last packet received, and that it is in native byte order.
.SH "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.
.PP
Note that Qt always uses native byte order, i.e. 67 is 67 in Qt; there is no need to call htons().
.SH "Protocol QSocketDevice::protocol () const"
Returns the socket's protocol family, which is one of Unknown, IPv4, or IPv6.
.PP
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.
.PP
See also Protocol and setSocket().
.SH "Q_LONG QSocketDevice::readBlock ( char * data, Q_ULONG maxlen )\fC [virtual]\fR"
Reads \fImaxlen\fR bytes from the socket into \fIdata\fR 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.
.PP
Reimplemented from QIODevice.
.SH "int QSocketDevice::receiveBufferSize () const"
Returns the size of the operating system receive buffer.
.PP
See also setReceiveBufferSize().
.SH "int QSocketDevice::sendBufferSize () const"
Returns the size of the operating system send buffer.
.PP
See also setSendBufferSize().
.SH "void QSocketDevice::setAddressReusable ( bool enable )\fC [virtual]\fR"
Sets the address of this socket to be usable by other sockets too if \fIenable\fR is TRUE, and to be used exclusively by this socket if \fIenable\fR is FALSE.
.PP
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.
.PP
See also addressReusable().
.SH "void QSocketDevice::setBlocking ( bool enable )\fC [virtual]\fR"
Makes the socket blocking if \fIenable\fR is TRUE or nonblocking if \fIenable\fR is FALSE.
.PP
Sockets are blocking by default, but we recommend using nonblocking socket operations, especially for GUI programs that need to be responsive.
.PP
\fBWarning:\fR On Windows, this function should be used with care since whenever you use a QSocketNotifier on Windows, the socket is immediately made nonblocking.
.PP
See also blocking() and isValid().
.SH "void QSocketDevice::setError ( Error err )\fC [protected]\fR"
Allows subclasses to set the error state to \fIerr\fR.
.SH "void QSocketDevice::setReceiveBufferSize ( uint size )\fC [virtual]\fR"
Sets the size of the operating system receive buffer to \fIsize\fR.
.PP
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.
.PP
The default is operating system-dependent. A socket that receives large amounts of data is probably best with a buffer size of 49152.
.SH "void QSocketDevice::setSendBufferSize ( uint size )\fC [virtual]\fR"
Sets the size of the operating system send buffer to \fIsize\fR.
.PP
The operating system send buffer size effectively limits how much data can be in transit at any one moment.
.PP
The default is operating system-dependent. A socket that sends large amounts of data is probably best with a buffer size of 49152.
.SH "void QSocketDevice::setSocket ( int socket, Type type )\fC [virtual]\fR"
Sets the socket device to operate on the existing socket \fIsocket\fR.
.PP
The \fItype\fR 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.
.PP
Any existing socket is closed.
.PP
See also isValid() and close().
.SH "int QSocketDevice::socket () const"
Returns the socket number, or -1 if it is an invalid socket.
.PP
See also isValid() and type().
.SH "Type QSocketDevice::type () const"
Returns the socket type which is either QSocketDevice::Stream or QSocketDevice::Datagram.
.PP
See also socket().
.SH "Q_LONG QSocketDevice::waitForMore ( int msecs, bool * timeout = 0 ) const"
Wait up to \fImsecs\fR milliseconds for more data to be available. If \fImsecs\fR is -1 the call will block indefinitely.
.PP
Returns the number of bytes available for reading, or -1 if an error occurred.
.PP
If \fItimeout\fR is non-null and no error occurred (i.e. it does not return -1): this function sets \fI*timeout\fR to TRUE, if the reason for returning was that the timeout was reached; otherwise it sets \fI*timeout\fR to FALSE. This is useful to find out if the peer closed the connection.
.PP
\fBWarning:\fR This is a blocking call and should be avoided in event driven applications.
.PP
See also bytesAvailable().
.SH "Q_LONG QSocketDevice::writeBlock ( const char * data, Q_ULONG len )\fC [virtual]\fR"
Writes \fIlen\fR bytes to the socket from \fIdata\fR and returns the number of bytes written. Returns -1 if an error occurred.
.PP
This is used for QSocketDevice::Stream sockets.
.PP
Reimplemented from QIODevice.
.SH "Q_LONG QSocketDevice::writeBlock ( const char * data, Q_ULONG len, const QHostAddress & host, Q_UINT16 port )\fC [virtual]\fR"
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
.PP
Writes \fIlen\fR bytes to the socket from \fIdata\fR and returns the number of bytes written. Returns -1 if an error occurred.
.PP
This is used for QSocketDevice::Datagram sockets. You must
specify the \fIhost\fR and \fIport\fR of the destination of the data.

.SH "SEE ALSO"
.BR http://doc.trolltech.com/qsocketdevice.html
.BR http://www.trolltech.com/faq/tech.html
.SH COPYRIGHT
Copyright 1992-2001 Trolltech AS, http://www.trolltech.com.  See the
license file included in the distribution for a complete license
statement.
.SH AUTHOR
Generated automatically from the source code.
.SH BUGS
If you find a bug in Qt, please report it as described in
.BR http://doc.trolltech.com/bughowto.html .
Good bug reports help us to help you. Thank you.
.P
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.P
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