QLocalSocket Class
The QLocalSocket class provides a local socket. More...
Header: | #include <QLocalSocket> |
qmake: | QT += network |
Since: | Qt 4.4 |
Inherits: | QIODevice |
Public Types
enum | LocalSocketError { ConnectionRefusedError, PeerClosedError, ServerNotFoundError, SocketAccessError, ..., UnknownSocketError } |
enum | LocalSocketState { UnconnectedState, ConnectingState, ConnectedState, ClosingState } |
Public Functions
QLocalSocket(QObject *parent = nullptr) | |
virtual | ~QLocalSocket() |
void | abort() |
void | connectToServer(QIODevice::OpenMode openMode = ReadWrite) |
void | connectToServer(const QString &name, QIODevice::OpenMode openMode = ReadWrite) |
void | disconnectFromServer() |
QLocalSocket::LocalSocketError | error() const |
bool | flush() |
QString | fullServerName() const |
bool | isValid() const |
qint64 | readBufferSize() const |
QString | serverName() const |
void | setReadBufferSize(qint64 size) |
void | setServerName(const QString &name) |
bool | setSocketDescriptor(qintptr socketDescriptor, QLocalSocket::LocalSocketState socketState = ConnectedState, QIODevice::OpenMode openMode = ReadWrite) |
qintptr | socketDescriptor() const |
QLocalSocket::LocalSocketState | state() const |
bool | waitForConnected(int msecs = 30000) |
bool | waitForDisconnected(int msecs = 30000) |
Reimplemented Public Functions
virtual qint64 | bytesAvailable() const override |
virtual qint64 | bytesToWrite() const override |
virtual bool | canReadLine() const override |
virtual void | close() override |
virtual bool | isSequential() const override |
virtual bool | open(QIODevice::OpenMode openMode = ReadWrite) override |
virtual bool | waitForBytesWritten(int msecs = 30000) override |
virtual bool | waitForReadyRead(int msecs = 30000) override |
Signals
void | connected() |
void | disconnected() |
void | error(QLocalSocket::LocalSocketError socketError) |
void | stateChanged(QLocalSocket::LocalSocketState socketState) |
Reimplemented Protected Functions
virtual qint64 | readData(char *, qint64) override |
virtual qint64 | writeData(const char *, qint64) override |
Additional Inherited Members
- 1 property inherited from QObject
- 1 public slot inherited from QObject
- 1 public variable inherited from QIODevice
- 1 public variable inherited from QObject
- 2 static public members inherited from QIODevice
- 10 static public members inherited from QObject
- 5 protected functions inherited from QIODevice
- 9 protected functions inherited from QObject
- 2 protected variables inherited from QObject
Detailed Description
The QLocalSocket class provides a local socket.
On Windows this is a named pipe and on Unix this is a local domain socket.
If an error occurs, socketError() returns the type of error, and errorString() can be called to get a human readable description of what happened.
Although QLocalSocket is designed for use with an event loop, it's possible to use it without one. In that case, you must use waitForConnected(), waitForReadyRead(), waitForBytesWritten(), and waitForDisconnected() which blocks until the operation is complete or the timeout expires.
See also QLocalServer.
Member Type Documentation
enum QLocalSocket::LocalSocketError
The LocalServerError enumeration represents the errors that can occur. The most recent error can be retrieved through a call to QLocalSocket::error().
Constant | Value | Description |
---|---|---|
QLocalSocket::ConnectionRefusedError | QAbstractSocket::ConnectionRefusedError | The connection was refused by the peer (or timed out). |
QLocalSocket::PeerClosedError | QAbstractSocket::RemoteHostClosedError | The remote socket closed the connection. Note that the client socket (i.e., this socket) will be closed after the remote close notification has been sent. |
QLocalSocket::ServerNotFoundError | QAbstractSocket::HostNotFoundError | The local socket name was not found. |
QLocalSocket::SocketAccessError | QAbstractSocket::SocketAccessError | The socket operation failed because the application lacked the required privileges. |
QLocalSocket::SocketResourceError | QAbstractSocket::SocketResourceError | The local system ran out of resources (e.g., too many sockets). |
QLocalSocket::SocketTimeoutError | QAbstractSocket::SocketTimeoutError | The socket operation timed out. |
QLocalSocket::DatagramTooLargeError | QAbstractSocket::DatagramTooLargeError | The datagram was larger than the operating system's limit (which can be as low as 8192 bytes). |
QLocalSocket::ConnectionError | QAbstractSocket::NetworkError | An error occurred with the connection. |
QLocalSocket::UnsupportedSocketOperationError | QAbstractSocket::UnsupportedSocketOperationError | The requested socket operation is not supported by the local operating system. |
QLocalSocket::OperationError | QAbstractSocket::OperationError | An operation was attempted while the socket was in a state that did not permit it. |
QLocalSocket::UnknownSocketError | QAbstractSocket::UnknownSocketError | An unidentified error occurred. |
enum QLocalSocket::LocalSocketState
This enum describes the different states in which a socket can be.
Constant | Value | Description |
---|---|---|
QLocalSocket::UnconnectedState | QAbstractSocket::UnconnectedState | The socket is not connected. |
QLocalSocket::ConnectingState | QAbstractSocket::ConnectingState | The socket has started establishing a connection. |
QLocalSocket::ConnectedState | QAbstractSocket::ConnectedState | A connection is established. |
QLocalSocket::ClosingState | QAbstractSocket::ClosingState | The socket is about to close (data may still be waiting to be written). |
See also QLocalSocket::state().
Member Function Documentation
QLocalSocket::QLocalSocket(QObject *parent = nullptr)
Creates a new local socket. The parent argument is passed to QObject's constructor.
[virtual]
QLocalSocket::~QLocalSocket()
Destroys the socket, closing the connection if necessary.
void QLocalSocket::abort()
[override virtual]
qint64 QLocalSocket::bytesAvailable() const
[override virtual]
qint64 QLocalSocket::bytesToWrite() const
[override virtual]
bool QLocalSocket::canReadLine() const
[override virtual]
void QLocalSocket::close()
void QLocalSocket::connectToServer(QIODevice::OpenMode openMode = ReadWrite)
void QLocalSocket::connectToServer(const QString &name, QIODevice::OpenMode openMode = ReadWrite)
This is an overloaded function.
Set the server name and attempts to make a connection to it.
The socket is opened in the given openMode and first enters ConnectingState. If a connection is established, QLocalSocket enters ConnectedState and emits connected().
After calling this function, the socket can emit error() to signal that an error occurred.
See also state(), serverName(), and waitForConnected().
[signal]
void QLocalSocket::connected()
void QLocalSocket::disconnectFromServer()
[signal]
void QLocalSocket::disconnected()
QLocalSocket::LocalSocketError QLocalSocket::error() const
[signal]
void QLocalSocket::error(QLocalSocket::LocalSocketError socketError)
Note: Signal error is overloaded in this class. To connect to this signal by using the function pointer syntax, Qt provides a convenient helper for obtaining the function pointer as shown in this example:
connect(localSocket, QOverload<QLocalSocket::LocalSocketError>::of(&QLocalSocket::error), [=](QLocalSocket::LocalSocketError socketError){ /* ... */ });
bool QLocalSocket::flush()
QString QLocalSocket::fullServerName() const
Returns the server path that the socket is connected to.
Note: The return value of this function is platform specific.
See also connectToServer() and serverName().
[override virtual]
bool QLocalSocket::isSequential() const
Reimplemented from QIODevice::isSequential().
bool QLocalSocket::isValid() const
[override virtual]
bool QLocalSocket::open(QIODevice::OpenMode openMode = ReadWrite)
qint64 QLocalSocket::readBufferSize() const
See also setReadBufferSize().
[override virtual protected]
qint64 QLocalSocket::readData(char *, qint64)
QString QLocalSocket::serverName() const
Returns the name of the peer as specified by setServerName(), or an empty QString if setServerName() has not been called or connectToServer() failed.
See also setServerName(), connectToServer(), and fullServerName().
void QLocalSocket::setReadBufferSize(qint64 size)
See also readBufferSize().
void QLocalSocket::setServerName(const QString &name)
Set the name of the peer to connect to. On Windows name is the name of a named pipe; on Unix name is the name of a local domain socket.
This function must be called when the socket is not connected.
This function was introduced in Qt 5.1.
See also serverName().
bool QLocalSocket::setSocketDescriptor(qintptr socketDescriptor, QLocalSocket::LocalSocketState socketState = ConnectedState, QIODevice::OpenMode openMode = ReadWrite)
See also socketDescriptor().
qintptr QLocalSocket::socketDescriptor() const
See also setSocketDescriptor().
QLocalSocket::LocalSocketState QLocalSocket::state() const
Returns the state of the socket.
See also error().