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## com.trolltech.qt.network
Class QAbstractSocket

    java.lang.Object
      com.trolltech.qt.internal.QSignalEmitterInternal
          com.trolltech.qt.QSignalEmitter
              com.trolltech.qt.QtJambiObject
                  com.trolltech.qt.core.QObject
                      com.trolltech.qt.core.QIODevice
                          com.trolltech.qt.network.QAbstractSocket

All Implemented Interfaces:
  QtJambiInterface

Direct Known Subclasses:
  QTcpSocket, QUdpSocket

    public class QAbstractSocket

extends QIODevice

The `QAbstractSocket` class provides the base functionality common to all socket types. `QAbstractSocket` is the base class for `QTcpSocket` and `QUdpSocket` and contains all common functionality of these two classes. If you need a socket, you have two options:

- Instantiate `QTcpSocket` or `QUdpSocket`.
- Create a native socket descriptor, instantiate `QAbstractSocket`, and call `setSocketDescriptor()` to wrap the native socket.

TCP (Transmission Control Protocol) is a reliable, stream-oriented, connection-oriented transport protocol. UDP (User Datagram Protocol) is an unreliable, datagram-oriented, connectionless protocol. In practice, this means that TCP is better suited for continuous transmission of data, whereas the more lightweight UDP can be used when reliability isn't important.

`QAbstractSocket`'s API unifies most of the differences between the two protocols. For example, although UDP is connectionless, `connectToHost()` establishes a virtual connection for UDP sockets, enabling you to use `QAbstractSocket` in more or less the same way regardless of the underlying protocol. Internally, `QAbstractSocket` remembers the address and port passed to `connectToHost()`, and functions like `read()` and `write()` use these values.

At any time, `QAbstractSocket` has a state (returned by `state()`). The initial state is `UnconnectedState` . After calling `connectToHost()`, the socket first enters `HostLookupState` . If the host is found, `QAbstractSocket` enters `ConnectingState` and emits the `hostFound()` signal. When the connection has been established, it enters `ConnectedState` and emits `connected()` . If an error occurs at any stage, `error()` is emitted. Whenever the state changes, `stateChanged()` is emitted. For convenience, `isValid()` returns true if the socket is ready for reading and writing, but note that the socket's state must be `ConnectedState` before reading and writing can occur.

Read or write data by calling `read()` or `write()`, or use the convenience functions `readLine()` and `readAll()`. `QAbstractSocket` also inherits getChar(), putChar(), and ungetChar() from `QIODevice`, which work on single bytes. For every chunk of data that has been written to the socket, the `bytesWritten()` signal is emitted.

The `readyRead()` signal is emitted every time a new chunk of data has arrived. `bytesAvailable()` then returns the number of bytes that are available for reading. Typically, you would connect the `readyRead()` signal to a slot and read all available data there. If you don't read all the data at once, the remaining data will still be available later, and any new incoming data will be appended to `QAbstractSocket`'s internal read buffer. To limit the size of the read buffer, call `setReadBufferSize()`.

To close the socket, call `disconnectFromHost()`. `QAbstractSocket` enters `QAbstractSocket::ClosingState` , then emits closing(). After all pending data has been written to the socket, `QAbstractSocket` actually closes the socket, enters QAbstractSocket::ClosedState, and emits `disconnected()` . If you want to abort a connection immediately, discarding all pending data, call `abort()` instead. If the remote host closes the connection, `QAbstractSocket` will emit error(`QAbstractSocket::RemoteHostClosedError` ), during which the socket state will still be `ConnectedState` , and then the `disconnected()` signal will be emitted.

The port and address of the connected peer is fetched by calling `peerPort()` and `peerAddress()`. `peerName()` returns the host name of the peer, as passed to `connectToHost()`. `localPort()` and `localAddress()` return the port and address of the local socket.

`QAbstractSocket` provides a set of functions that suspend the calling thread until certain signals are emitted. These functions can be used to implement blocking sockets:

- `waitForConnected()` blocks until a connection has been established.
- `waitForReadyRead()` blocks until new data is available for reading.
- `waitForBytesWritten()` blocks until one payload of data has been written to the socket.
- `waitForDisconnected()` blocks until the connection has closed.

We show an example:

            int numRead = 0, numReadTotal = 0;
            byte buffer[] = new byte[50];

            while (true) {
                numRead  = socket.read(buffer);

                // do whatever with array

                numReadTotal += numRead;
                if (numRead == 0 && !socket.waitForReadyRead(1000))
                    break;
            }

If `waitForReadyRead()` returns false, the connection has been closed or an error has occurred.

Programming with a blocking socket is radically different from programming with a non-blocking socket. A blocking socket doesn't require an event loop and typically leads to simpler code. However, in a GUI application, blocking sockets should only be used in non-GUI threads, to avoid freezing the user interface. See the network/fortuneclient and network/blockingfortuneclient examples for an overview of both approaches.

`QAbstractSocket` can be used with `QTextStream` and `QDataStream`'s stream operators (operator<<() and operator>>()). There is one issue to be aware of, though: You must make sure that enough data is available before attempting to read it using operator>>().

See also:
  `QFtp`, `QHttp`, and `QTcpServer`.

Nested Class Summary
`static class` | `QAbstractSocket.NetworkLayerProtocol` This enum describes the network layer protocol values used in Qt.
`static class` | `QAbstractSocket.SocketError` The `SocketError` enumeration represents the various errors that can occur on a Unix domain socket.
`static class` | `QAbstractSocket.SocketState` The `SocketState` enumeration represents the connection state of a QUnixSocket instance.
`static class` | `QAbstractSocket.SocketType` This enum describes the transport layer protocol.

Nested classes/interfaces inherited from class com.trolltech.qt.core.QIODevice
`QIODevice.OpenMode, QIODevice.OpenModeFlag`

Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
`QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9`

Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
`com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal`

Field Summary
`QSignalEmitter.Signal0` | `connected` This signal is emitted after `connectToHost()` has been called and a connection has been successfully established.
`QSignalEmitter.Signal0` | `disconnected` This signal is emitted when the socket has been disconnected.
`QSignalEmitter.Signal1` | `error` This signal takes 1 generic argument(s).
`QSignalEmitter.Signal0` | `hostFound` This signal is emitted after `connectToHost()` has been called and the host lookup has succeeded.
`QSignalEmitter.Signal2` | `proxyAuthenticationRequired` This signal takes 2 generic argument(s).
`QSignalEmitter.Signal1` | `stateChanged` This signal takes 1 generic argument(s).

Fields inherited from class com.trolltech.qt.core.QIODevice
`aboutToClose, bytesWritten, readChannelFinished, readyRead`

Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
`currentSender`

Constructor Summary
`QAbstractSocket(QAbstractSocket.SocketType socketType, QObject parent)` Creates a new abstract socket of type `socketType`.

Method Summary
`void` | `abort()` Aborts the current connection and resets the socket.
`void` | `connectToHost(QHostAddress host, int port)` Attempts to make a connection to `address` on port `port`.
`void` | `connectToHost(QHostAddress host, int port, QIODevice.OpenMode mode)` Attempts to make a connection to `address` on port `port`.
`void` | `connectToHost(QHostAddress host, int port, QIODevice.OpenModeFlag[] mode)` Attempts to make a connection to `address` on port `port`.
`void` | `connectToHost(java.lang.String host, int port)` Attempts to make a connection to `hostName` on the given `port`.
`void` | `connectToHost(java.lang.String host, int port, QIODevice.OpenMode mode)` Attempts to make a connection to `hostName` on the given `port`.
`void` | `connectToHost(java.lang.String host, int port, QIODevice.OpenModeFlag[] mode)` Attempts to make a connection to `hostName` on the given `port`.
`void` | `disconnectFromHost()` Attempts to close the socket.
`protected void` | `disconnectFromHostImplementation()` Contains the implementation of `disconnectFromHost()`.
`QAbstractSocket.SocketError` | `error()` Returns the type of error that last occurred.
`boolean` | `flush()` This function writes as much as possible from the internal write buffer to the underlying network socket, without blocking.
`boolean` | `isValid()` Returns true if the socket is valid and ready for use; otherwise returns false.
`QHostAddress` | `localAddress()` Returns the host address of the local socket if available; otherwise returns `QHostAddress::Null` .
`int` | `localPort()` Returns the host port number (in native byte order) of the local socket if available; otherwise returns 0.
`QHostAddress` | `peerAddress()` Returns the address of the connected peer if the socket is in `ConnectedState` ; otherwise returns `QHostAddress::Null` .
`java.lang.String` | `peerName()` Returns the name of the peer as specified by `connectToHost()`, or an empty QString if `connectToHost()` has not been called.
`int` | `peerPort()` Returns the port of the connected peer if the socket is in ConnectedState; otherwise returns 0.
`QNetworkProxy` | `proxy()` Returns the network proxy for this socket.
`long` | `readBufferSize()` Returns the size of the internal read buffer.
`protected void` | `setLocalAddress(QHostAddress address)` Sets the address on the local side of a connection to `address`.
`protected void` | `setLocalPort(int port)` Sets the local port of this QAbstractSocket to `port`.
`protected void` | `setPeerAddress(QHostAddress address)` Sets the address of the remote side of the connection to `address`.
`protected void` | `setPeerName(java.lang.String name)` Sets the host name of the remote peer to `name`.
`protected void` | `setPeerPort(int port)` Sets the peer port of this QAbstractSocket to `port`.
`void` | `setProxy(QNetworkProxy networkProxy)` Sets the explicit network proxy for this socket to `networkProxy`.
`void` | `setReadBufferSize(long size)` Sets the size of `QAbstractSocket`'s internal read buffer to be `size` bytes.
`boolean` | `setSocketDescriptor(int socketDescriptor)` Initializes `QAbstractSocket` with the native socket descriptor `socketDescriptor`.
`boolean` | `setSocketDescriptor(int socketDescriptor, QAbstractSocket.SocketState state)` Initializes `QAbstractSocket` with the native socket descriptor `socketDescriptor`.
`boolean` | `setSocketDescriptor(int socketDescriptor, QAbstractSocket.SocketState state, QIODevice.OpenMode openMode)` Initializes `QAbstractSocket` with the native socket descriptor `socketDescriptor`.
`boolean` | `setSocketDescriptor(int socketDescriptor, QAbstractSocket.SocketState state, QIODevice.OpenModeFlag[] openMode)` Initializes `QAbstractSocket` with the native socket descriptor `socketDescriptor`.
`protected void` | `setSocketError(QAbstractSocket.SocketError socketError)` Sets the type of error that last occurred to `socketError`.
`protected void` | `setSocketState(QAbstractSocket.SocketState state)` Sets the state of the socket to `state`.
`int` | `socketDescriptor()` Returns the native socket descriptor of the `QAbstractSocket` object if this is available; otherwise returns -1.
`QAbstractSocket.SocketType` | `socketType()` Returns the socket type (TCP, UDP, or other).
`QAbstractSocket.SocketState` | `state()` Returns the state of the socket.
`boolean` | `waitForConnected()` Waits until the socket is connected, up to `msecs` milliseconds.
`boolean` | `waitForConnected(int msecs)` Waits until the socket is connected, up to `msecs` milliseconds.
`boolean` | `waitForDisconnected()` Waits until the socket has disconnected, up to `msecs` milliseconds.
`boolean` | `waitForDisconnected(int msecs)` Waits until the socket has disconnected, up to `msecs` milliseconds.

Methods inherited from class com.trolltech.qt.core.QIODevice
`atEnd, bytesAvailable, bytesToWrite, canReadLine, close, errorString, getByte, isOpen, isReadable, isSequential, isTextModeEnabled, isWritable, open, open, openMode, peek, peek, pos, putByte, read, read, readAll, readData, readLine, readLine, readLine, readLineData, reset, seek, setErrorString, setOpenMode, setOpenMode, setTextModeEnabled, size, ungetByte, waitForBytesWritten, waitForReadyRead, write, write, writeData`

Methods inherited from class com.trolltech.qt.core.QObject
`childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty`

Methods inherited from class com.trolltech.qt.QtJambiObject
`dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr`

Methods inherited from class com.trolltech.qt.QSignalEmitter
`blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread`

Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
`__qt_signalInitialization`

Methods inherited from class java.lang.Object
`clone, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Methods inherited from interface com.trolltech.qt.QtJambiInterface
`disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership`

Field Detail

### connected

    public final QSignalEmitter.Signal0 connected

  This signal is emitted after `connectToHost()` has been called and a connection has been successfully established.

See also:
  `connectToHost()`, and `disconnected()` .

### disconnected

    public final QSignalEmitter.Signal0 disconnected

  This signal is emitted when the socket has been disconnected.

  Warning: If you need to delete the sender() of this signal in a slot connected to it, use the deleteLater() function.

See also:
  `connectToHost()`, `disconnectFromHost()`, and `abort()`.

### error

    public final QSignalEmitter.Signal1 error

  This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.network.QAbstractSocket$SocketError(named: socketError)>:

  This signal is emitted after an error occurred. The `socketError` parameter describes the type of error that occurred.

  `QAbstractSocket::SocketError` is not a registered metatype, so for queued connections, you will have to register it with Q_REGISTER_METATYPE.

See also:
  `error()`, and `errorString()`.

### hostFound

    public final QSignalEmitter.Signal0 hostFound

  This signal is emitted after `connectToHost()` has been called and the host lookup has succeeded.

See also:
  `connected()` .

### stateChanged

    public final QSignalEmitter.Signal1 stateChanged

  This signal takes 1 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.network.QAbstractSocket$SocketState(named: socketState)>:

  This signal is emitted whenever `QAbstractSocket`'s state changes. The `socketState` parameter is the new state.

  `QAbstractSocket::SocketState` is not a registered metatype, so for queued connections, you will have to register it with Q_REGISTER_METATYPE.

See also:
  `state()`.

### proxyAuthenticationRequired

    public QSignalEmitter.Signal2 proxyAuthenticationRequired

  This signal takes 2 generic argument(s). We list their type and the name they go by in the description of this signal. <com.trolltech.qt.network.QNetworkProxy(named: proxy), com.trolltech.qt.network.QAuthenticator(named: authenticator)>:

  This signal can be emitted when a `proxy` that requires authentication is used. The `authenticator` object can then be filled in with the required details to allow authentication and continue the connection.

  Note: It is not possible to use a QueuedConnection to connect to this signal, as the connection will fail if the authenticator has not been filled in with new information when the signal returns.

See also:
  `QAuthenticator`, and `QNetworkProxy`.

Constructor Detail

### QAbstractSocket

    public QAbstractSocket(QAbstractSocket.SocketType socketType,
                           QObject parent)

  Creates a new abstract socket of type `socketType`. The `parent` argument is passed to `QObject`'s constructor.

See also:
  `socketType()`, `QTcpSocket`, and `QUdpSocket`.

Method Detail

### abort

    public void abort()

  Aborts the current connection and resets the socket. Unlike `disconnectFromHost()`, this function immediately closes the socket, discarding any pending data in the write buffer.

See also:
  `disconnectFromHost()`, and `close()`.

### disconnectFromHost

    public final void disconnectFromHost()

  Attempts to close the socket. If there is pending data waiting to be written, `QAbstractSocket` will enter `ClosingState` and wait until all data has been written. Eventually, it will enter `UnconnectedState` and emit the `disconnected()` signal.

See also:
  `connectToHost()`.

### disconnectFromHostImplementation

    protected void disconnectFromHostImplementation()

  Contains the implementation of `disconnectFromHost()`.

### error

    public final QAbstractSocket.SocketError error()

  Returns the type of error that last occurred.

See also:
  `state()`, and `errorString()`.

### flush

    public boolean flush()

  This function writes as much as possible from the internal write buffer to the underlying network socket, without blocking. If any data was written, this function returns true; otherwise false is returned.

  Call this function if you need `QAbstractSocket` to start sending buffered data immediately. The number of bytes successfully written depends on the operating system. In most cases, you do not need to call this function, because `QAbstractSocket` will start sending data automatically once control goes back to the event loop. In the absence of an event loop, call `waitForBytesWritten()` instead.

See also:
  `write()`, and `waitForBytesWritten()`.

### isValid

    public final boolean isValid()

  Returns true if the socket is valid and ready for use; otherwise returns false.

  Note: The socket's state must be `ConnectedState` before reading and writing can occur.

See also:
  `state()`.

### localAddress

    public final QHostAddress localAddress()

  Returns the host address of the local socket if available; otherwise returns `QHostAddress::Null` .

  This is normally the main IP address of the host, but can be `QHostAddress::LocalHost` (127.0.0.1) for connections to the local host.

See also:
  `localPort()`, `peerAddress()`, and `setLocalAddress()`.

### peerAddress

    public final QHostAddress peerAddress()

  Returns the address of the connected peer if the socket is in `ConnectedState` ; otherwise returns `QHostAddress::Null` .

See also:
  `peerName()`, `peerPort()`, `localAddress()`, and `setPeerAddress()`.

### peerName

    public final java.lang.String peerName()

  Returns the name of the peer as specified by `connectToHost()`, or an empty QString if `connectToHost()` has not been called.

See also:
  `peerAddress()`, `peerPort()`, and `setPeerName()`.

### proxy

    public final QNetworkProxy proxy()

  Returns the network proxy for this socket. By default `QNetworkProxy::DefaultProxy` is used.

See also:
  `setProxy()`, and `QNetworkProxy`.

### readBufferSize

    public final long readBufferSize()

  Returns the size of the internal read buffer. This limits the amount of data that the client can receive before you call `read()` or `readAll()`.

  A read buffer size of 0 (the default) means that the buffer has no size limit, ensuring that no data is lost.

See also:
  `setReadBufferSize()`, and `read()`.

### setLocalAddress

    protected final void setLocalAddress(QHostAddress address)

  Sets the address on the local side of a connection to `address`.

  You can call this function in a subclass of `QAbstractSocket` to change the return value of the `localAddress()` function after a connection has been established. This feature is commonly used by proxy connections for virtual connection settings.

  Note that this function does not bind the local address of the socket prior to a connection (e.g., `QUdpSocket::bind()`).

See also:
  `localAddress()`, `setLocalPort()`, and `setPeerAddress()`.

### setPeerAddress

    protected final void setPeerAddress(QHostAddress address)

  Sets the address of the remote side of the connection to `address`.

  You can call this function in a subclass of `QAbstractSocket` to change the return value of the `peerAddress()` function after a connection has been established. This feature is commonly used by proxy connections for virtual connection settings.

See also:
  `peerAddress()`, `setPeerPort()`, and `setLocalAddress()`.

### setPeerName

    protected final void setPeerName(java.lang.String name)

  Sets the host name of the remote peer to `name`.

  You can call this function in a subclass of `QAbstractSocket` to change the return value of the `peerName()` function after a connection has been established. This feature is commonly used by proxy connections for virtual connection settings.

See also:
  `peerName()`.

### setProxy

    public final void setProxy(QNetworkProxy networkProxy)

  Sets the explicit network proxy for this socket to `networkProxy`.

  To disable the use of a proxy for this socket, use the `QNetworkProxy::NoProxy` proxy type:
  The following code example is written in c++.

              socket->setProxy(QNetworkProxy::NoProxy);

See also:
  `proxy()`, and `QNetworkProxy`.

### setReadBufferSize

    public void setReadBufferSize(long size)

  Sets the size of `QAbstractSocket`'s internal read buffer to be `size` bytes.

  If the buffer size is limited to a certain size, `QAbstractSocket` won't buffer more than this size of data. Exceptionally, a buffer size of 0 means that the read buffer is unlimited and all incoming data is buffered. This is the default.

  This option is useful if you only read the data at certain points in time (e.g., in a real-time streaming application) or if you want to protect your socket against receiving too much data, which may eventually cause your application to run out of memory.

  Only `QTcpSocket` uses `QAbstractSocket`'s internal buffer; `QUdpSocket` does not use any buffering at all, but rather relies on the implicit buffering provided by the operating system. Because of this, calling this function on `QUdpSocket` has no effect.

See also:
  `readBufferSize()`, and `read()`.

### setSocketDescriptor

    public final boolean setSocketDescriptor(int socketDescriptor,
                                             QAbstractSocket.SocketState state,
                                             QIODevice.OpenModeFlag[] openMode)

  Initializes `QAbstractSocket` with the native socket descriptor `socketDescriptor`. Returns true if `socketDescriptor` is accepted as a valid socket descriptor; otherwise returns false. The socket is opened in the mode specified by `openMode`, and enters the socket state specified by `socketState`.

  Note: It is not possible to initialize two abstract sockets with the same native socket descriptor.

See also:
  `socketDescriptor()`.

### setSocketDescriptor

    public final boolean setSocketDescriptor(int socketDescriptor,
                                             QAbstractSocket.SocketState state)

  Initializes `QAbstractSocket` with the native socket descriptor `socketDescriptor`. Returns true if `socketDescriptor` is accepted as a valid socket descriptor; otherwise returns false. The socket is opened in the mode specified by `openMode`, and enters the socket state specified by `socketState`.

  Note: It is not possible to initialize two abstract sockets with the same native socket descriptor.

See also:
  `socketDescriptor()`.

### setSocketDescriptor

    public final boolean setSocketDescriptor(int socketDescriptor)

  Initializes `QAbstractSocket` with the native socket descriptor `socketDescriptor`. Returns true if `socketDescriptor` is accepted as a valid socket descriptor; otherwise returns false. The socket is opened in the mode specified by `openMode`, and enters the socket state specified by `socketState`.

  Note: It is not possible to initialize two abstract sockets with the same native socket descriptor.

See also:
  `socketDescriptor()`.

### setSocketDescriptor

    public boolean setSocketDescriptor(int socketDescriptor,
                                       QAbstractSocket.SocketState state,
                                       QIODevice.OpenMode openMode)

  Initializes `QAbstractSocket` with the native socket descriptor `socketDescriptor`. Returns true if `socketDescriptor` is accepted as a valid socket descriptor; otherwise returns false. The socket is opened in the mode specified by `openMode`, and enters the socket state specified by `socketState`.

  Note: It is not possible to initialize two abstract sockets with the same native socket descriptor.

See also:
  `socketDescriptor()`.

### setSocketError

    protected final void setSocketError(QAbstractSocket.SocketError socketError)

  Sets the type of error that last occurred to `socketError`.

See also:
  `setSocketState()`, and `setErrorString()`.

### setSocketState

    protected final void setSocketState(QAbstractSocket.SocketState state)

  Sets the state of the socket to `state`.

See also:
  `state()`.

### socketDescriptor

    public final int socketDescriptor()

  Returns the native socket descriptor of the `QAbstractSocket` object if this is available; otherwise returns -1.

  If the socket is using `QNetworkProxy`, the returned descriptor may not be usable with native socket functions.

  The socket descriptor is not available when `QAbstractSocket` is in `UnconnectedState` .

See also:
  `setSocketDescriptor()`.

### socketType

    public final QAbstractSocket.SocketType socketType()

  Returns the socket type (TCP, UDP, or other).

See also:
  `QTcpSocket`, and `QUdpSocket`.

### state

    public final QAbstractSocket.SocketState state()

  Returns the state of the socket.

See also:
  `error()`.

### waitForConnected

    public final boolean waitForConnected()

  Waits until the socket is connected, up to `msecs` milliseconds. If the connection has been established, this function returns true; otherwise it returns false. In the case where it returns false, you can call `error()` to determine the cause of the error.

  The following example waits up to one second for a connection to be established:
  The following code example is written in c++.

              socket->connectToHost("imap", 143);
              if (socket->waitForConnected(1000))
                  qDebug("Connected!");

  If msecs is -1, this function will not time out.

  Note: This function may wait slightly longer than `msecs`, depending on the time it takes to complete the host lookup.

See also:
  `connectToHost()`, and `connected()` .

### waitForConnected

    public boolean waitForConnected(int msecs)

  Waits until the socket is connected, up to `msecs` milliseconds. If the connection has been established, this function returns true; otherwise it returns false. In the case where it returns false, you can call `error()` to determine the cause of the error.

  The following example waits up to one second for a connection to be established:
  The following code example is written in c++.

              socket->connectToHost("imap", 143);
              if (socket->waitForConnected(1000))
                  qDebug("Connected!");

  If msecs is -1, this function will not time out.

  Note: This function may wait slightly longer than `msecs`, depending on the time it takes to complete the host lookup.

See also:
  `connectToHost()`, and `connected()` .

### waitForDisconnected

    public final boolean waitForDisconnected()

  Waits until the socket has disconnected, up to `msecs` milliseconds. If the connection has been disconnected, this function returns true; otherwise it returns false. In the case where it returns false, you can call `error()` to determine the cause of the error.

  The following example waits up to one second for a connection to be closed:
  The following code example is written in c++.

              socket->disconnectFromHost();
                  if (socket->state() == QAbstractSocket::UnconnectedState ||
                      socket->waitForDisconnected(1000))
                      qDebug("Disconnected!");

  If msecs is -1, this function will not time out.

See also:
  `disconnectFromHost()`, and `close()`.

### waitForDisconnected

    public boolean waitForDisconnected(int msecs)

  Waits until the socket has disconnected, up to `msecs` milliseconds. If the connection has been disconnected, this function returns true; otherwise it returns false. In the case where it returns false, you can call `error()` to determine the cause of the error.

  The following example waits up to one second for a connection to be closed:
  The following code example is written in c++.

              socket->disconnectFromHost();
                  if (socket->state() == QAbstractSocket::UnconnectedState ||
                      socket->waitForDisconnected(1000))
                      qDebug("Disconnected!");

  If msecs is -1, this function will not time out.

See also:
  `disconnectFromHost()`, and `close()`.

### connectToHost

    public final void connectToHost(java.lang.String host,
                                    int port,
                                    QIODevice.OpenMode mode)

  Attempts to make a connection to `hostName` on the given `port`.

  The socket is opened in the given `openMode` and first enters `HostLookupState` , then performs a host name lookup of `hostName`. If the lookup succeeds, `hostFound()` is emitted and `QAbstractSocket` enters `ConnectingState` . It then attempts to connect to the address or addresses returned by the lookup. Finally, if a connection is established, `QAbstractSocket` enters `ConnectedState` and emits `connected()` .

  At any point, the socket can emit `error()` to signal that an error occurred.

  `hostName` may be an IP address in string form (e.g., "43.195.83.32"), or it may be a host name (e.g., "www.trolltech.com"). `QAbstractSocket` will do a lookup only if required. `port` is in native byte order.

See also:
  `state()`, `peerName()`, `peerAddress()`, `peerPort()`, and `waitForConnected()`.

### connectToHost

    public final void connectToHost(java.lang.String host,
                                    int port,
                                    QIODevice.OpenModeFlag[] mode)

  Attempts to make a connection to `hostName` on the given `port`.

  The socket is opened in the given `openMode` and first enters `HostLookupState` , then performs a host name lookup of `hostName`. If the lookup succeeds, `hostFound()` is emitted and `QAbstractSocket` enters `ConnectingState` . It then attempts to connect to the address or addresses returned by the lookup. Finally, if a connection is established, `QAbstractSocket` enters `ConnectedState` and emits `connected()` .

  At any point, the socket can emit `error()` to signal that an error occurred.

  `hostName` may be an IP address in string form (e.g., "43.195.83.32"), or it may be a host name (e.g., "www.trolltech.com"). `QAbstractSocket` will do a lookup only if required. `port` is in native byte order.

See also:
  `state()`, `peerName()`, `peerAddress()`, `peerPort()`, and `waitForConnected()`.

### connectToHost

    public final void connectToHost(java.lang.String host,
                                    int port)

  Attempts to make a connection to `hostName` on the given `port`.

  The socket is opened in the given `openMode` and first enters `HostLookupState` , then performs a host name lookup of `hostName`. If the lookup succeeds, `hostFound()` is emitted and `QAbstractSocket` enters `ConnectingState` . It then attempts to connect to the address or addresses returned by the lookup. Finally, if a connection is established, `QAbstractSocket` enters `ConnectedState` and emits `connected()` .

  At any point, the socket can emit `error()` to signal that an error occurred.

  `hostName` may be an IP address in string form (e.g., "43.195.83.32"), or it may be a host name (e.g., "www.trolltech.com"). `QAbstractSocket` will do a lookup only if required. `port` is in native byte order.

See also:
  `state()`, `peerName()`, `peerAddress()`, `peerPort()`, and `waitForConnected()`.

### connectToHost

    public final void connectToHost(QHostAddress host,
                                    int port,
                                    QIODevice.OpenMode mode)

  Attempts to make a connection to `address` on port `port`.

### connectToHost

    public final void connectToHost(QHostAddress host,
                                    int port,
                                    QIODevice.OpenModeFlag[] mode)

  Attempts to make a connection to `address` on port `port`.

### connectToHost

    public final void connectToHost(QHostAddress host,
                                    int port)

  Attempts to make a connection to `address` on port `port`.

### localPort

    public final int localPort()

  Returns the host port number (in native byte order) of the local socket if available; otherwise returns 0.

### peerPort

    public final int peerPort()

  Returns the port of the connected peer if the socket is in ConnectedState; otherwise returns 0.

### setLocalPort

    protected final void setLocalPort(int port)

  Sets the local port of this QAbstractSocket to `port`.

### setPeerPort

    protected final void setPeerPort(int port)

  Sets the peer port of this QAbstractSocket to `port`.

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