class QAbstractSocket

The QAbstractSocket class provides the base functionality common to all socket types. More…

Inheritance diagram of PySide6.QtNetwork.QAbstractSocket

Inherited by: QUdpSocket, QTcpSocket, QSslSocket

Synopsis

Methods

Virtual methods

Signals

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

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:

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, errorOccurred() 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. The bytesWritten() signal is emitted when data has been written to the socket. Note that Qt does not limit the write buffer size. You can monitor its size by listening to this signal.

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 ClosingState . After all pending data has been written to the socket, QAbstractSocket actually closes the socket, enters UnconnectedState , 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 errorOccurred ( 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:

numRead = 0, numReadTotal = 0
buffer[50] = char()
forever {
    numRead = socket.read(buffer, 50)
    # do whatever with array
    numReadTotal += numRead
    if numRead == 0 and not socket.waitForReadyRead():
        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 fortuneclient and blockingfortuneclient examples for an overview of both approaches.

Note

We discourage the use of the blocking functions together with signals. One of the two possibilities should be used.

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>>().

class SocketType

This enum describes the transport layer protocol.

Constant

Description

QAbstractSocket.TcpSocket

TCP

QAbstractSocket.UdpSocket

UDP

QAbstractSocket.SctpSocket

SCTP

QAbstractSocket.UnknownSocketType

Other than TCP, UDP and SCTP

See also

socketType()

class NetworkLayerProtocol

This enum describes the network layer protocol values used in Qt.

Constant

Description

QAbstractSocket.IPv4Protocol

IPv4

QAbstractSocket.IPv6Protocol

IPv6

QAbstractSocket.AnyIPProtocol

Either IPv4 or IPv6

QAbstractSocket.UnknownNetworkLayerProtocol

Other than IPv4 and IPv6

See also

protocol()

class SocketError

This enum describes the socket errors that can occur.

Constant

Description

QAbstractSocket.ConnectionRefusedError

The connection was refused by the peer (or timed out).

QAbstractSocket.RemoteHostClosedError

The remote host closed the connection. Note that the client socket (i.e., this socket) will be closed after the remote close notification has been sent.

QAbstractSocket.HostNotFoundError

The host address was not found.

QAbstractSocket.SocketAccessError

The socket operation failed because the application lacked the required privileges.

QAbstractSocket.SocketResourceError

The local system ran out of resources (e.g., too many sockets).

QAbstractSocket.SocketTimeoutError

The socket operation timed out.

QAbstractSocket.DatagramTooLargeError

The datagram was larger than the operating system’s limit (which can be as low as 8192 bytes).

QAbstractSocket.NetworkError

An error occurred with the network (e.g., the network cable was accidentally plugged out).

QAbstractSocket.AddressInUseError

The address specified to bind() is already in use and was set to be exclusive.

QAbstractSocket.SocketAddressNotAvailableError

The address specified to bind() does not belong to the host.

QAbstractSocket.UnsupportedSocketOperationError

The requested socket operation is not supported by the local operating system (e.g., lack of IPv6 support).

QAbstractSocket.ProxyAuthenticationRequiredError

The socket is using a proxy, and the proxy requires authentication.

QAbstractSocket.SslHandshakeFailedError

The SSL/TLS handshake failed, so the connection was closed (only used in QSslSocket )

QAbstractSocket.UnfinishedSocketOperationError

Used by QAbstractSocketEngine only, The last operation attempted has not finished yet (still in progress in the background).

QAbstractSocket.ProxyConnectionRefusedError

Could not contact the proxy server because the connection to that server was denied

QAbstractSocket.ProxyConnectionClosedError

The connection to the proxy server was closed unexpectedly (before the connection to the final peer was established)

QAbstractSocket.ProxyConnectionTimeoutError

The connection to the proxy server timed out or the proxy server stopped responding in the authentication phase.

QAbstractSocket.ProxyNotFoundError

The proxy address set with setProxy() (or the application proxy) was not found.

QAbstractSocket.ProxyProtocolError

The connection negotiation with the proxy server failed, because the response from the proxy server could not be understood.

QAbstractSocket.OperationError

An operation was attempted while the socket was in a state that did not permit it.

QAbstractSocket.SslInternalError

The SSL library being used reported an internal error. This is probably the result of a bad installation or misconfiguration of the library.

QAbstractSocket.SslInvalidUserDataError

Invalid data (certificate, key, cypher, etc.) was provided and its use resulted in an error in the SSL library.

QAbstractSocket.TemporaryError

A temporary error occurred (e.g., operation would block and socket is non-blocking).

QAbstractSocket.UnknownSocketError

An unidentified error occurred.

See also

error() errorOccurred()

class SocketState

This enum describes the different states in which a socket can be.

Constant

Description

QAbstractSocket.UnconnectedState

The socket is not connected.

QAbstractSocket.HostLookupState

The socket is performing a host name lookup.

QAbstractSocket.ConnectingState

The socket has started establishing a connection.

QAbstractSocket.ConnectedState

A connection is established.

QAbstractSocket.BoundState

The socket is bound to an address and port.

QAbstractSocket.ClosingState

The socket is about to close (data may still be waiting to be written).

QAbstractSocket.ListeningState

For internal use only.

See also

state()

class SocketOption

This enum represents the options that can be set on a socket. If desired, they can be set after having received the connected() signal from the socket or after having received a new socket from a QTcpServer .

Constant

Description

QAbstractSocket.LowDelayOption

Try to optimize the socket for low latency. For a QTcpSocket this would set the TCP_NODELAY option and disable Nagle’s algorithm. Set this to 1 to enable.

QAbstractSocket.KeepAliveOption

Set this to 1 to enable the SO_KEEPALIVE socket option

QAbstractSocket.MulticastTtlOption

Set this to an integer value to set IP_MULTICAST_TTL (TTL for multicast datagrams) socket option.

QAbstractSocket.MulticastLoopbackOption

Set this to 1 to enable the IP_MULTICAST_LOOP (multicast loopback) socket option.

QAbstractSocket.TypeOfServiceOption

This option is not supported on Windows. This maps to the IP_TOS socket option. For possible values, see table below.

QAbstractSocket.SendBufferSizeSocketOption

Sets the socket send buffer size in bytes at the OS level. This maps to the SO_SNDBUF socket option. This option does not affect the QIODevice or QAbstractSocket buffers. This enum value has been introduced in Qt 5.3.

QAbstractSocket.ReceiveBufferSizeSocketOption

Sets the socket receive buffer size in bytes at the OS level. This maps to the SO_RCVBUF socket option. This option does not affect the QIODevice or QAbstractSocket buffers (see setReadBufferSize() ). This enum value has been introduced in Qt 5.3.

QAbstractSocket.PathMtuSocketOption

Retrieves the Path Maximum Transmission Unit (PMTU) value currently known by the IP stack, if any. Some IP stacks also allow setting the MTU for transmission. This enum value was introduced in Qt 5.11.

Possible values for TypeOfServiceOption are:

Value

Description

224

Network control

192

Internetwork control

160

CRITIC/ECP

128

Flash override

96

Flash

64

Immediate

32

Priority

0

Routine

See also

setSocketOption() socketOption()

Added in version 4.6.

class BindFlag

(inherits enum.Flag) This enum describes the different flags you can pass to modify the behavior of bind() .

Constant

Description

QAbstractSocket.ShareAddress

Allow other services to bind to the same address and port. This is useful when multiple processes share the load of a single service by listening to the same address and port (e.g., a web server with several pre-forked listeners can greatly improve response time). However, because any service is allowed to rebind, this option is subject to certain security considerations. Note that by combining this option with ReuseAddressHint, you will also allow your service to rebind an existing shared address. On Unix, this is equivalent to the SO_REUSEADDR socket option. On Windows, this is the default behavior, so this option is ignored.

QAbstractSocket.DontShareAddress

Bind the address and port exclusively, so that no other services are allowed to rebind. By passing this option to bind() , you are guaranteed that on success, your service is the only one that listens to the address and port. No services are allowed to rebind, even if they pass ReuseAddressHint. This option provides more security than ShareAddress, but on certain operating systems, it requires you to run the server with administrator privileges. On Unix and macOS, not sharing is the default behavior for binding an address and port, so this option is ignored. On Windows, this option uses the SO_EXCLUSIVEADDRUSE socket option.

QAbstractSocket.ReuseAddressHint

Provides a hint to QAbstractSocket that it should try to rebind the service even if the address and port are already bound by another socket. On Windows and Unix, this is equivalent to the SO_REUSEADDR socket option.

QAbstractSocket.DefaultForPlatform

The default option for the current platform. On Unix and macOS, this is equivalent to (DontShareAddress + ReuseAddressHint), and on Windows, it is equivalent to ShareAddress.
class PauseMode

(inherits enum.Flag) This enum describes the behavior of when the socket should hold back with continuing data transfer. The only notification currently supported is sslErrors() .

Constant

Description

QAbstractSocket.PauseNever

Do not pause data transfer on the socket. This is the default and matches the behavior of Qt 4.

QAbstractSocket.PauseOnSslErrors

Pause data transfer on the socket upon receiving an SSL error notification. I.E. sslErrors() .
__init__(socketType, parent)
Parameters:

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

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() close()

bind([port=0[, mode=QAbstractSocket.BindFlag.DefaultForPlatform]])
Parameters:

  • port – int

  • mode – Combination of BindFlag

Return type:

bool

This is an overloaded function.

Binds to QHostAddress :Any on port port, using the BindMode mode.

By default, the socket is bound using the DefaultForPlatform BindMode . If a port is not specified, a random port is chosen.

bind(address[, port=0[, mode=QAbstractSocket.BindFlag.DefaultForPlatform]])
Parameters:
Return type:

bool

Binds to address on port port, using the BindMode mode.

For UDP sockets, after binding, the signal QUdpSocket::readyRead() is emitted whenever a UDP datagram arrives on the specified address and port. Thus, this function is useful to write UDP servers.

For TCP sockets, this function may be used to specify which interface to use for an outgoing connection, which is useful in case of multiple network interfaces.

By default, the socket is bound using the DefaultForPlatform BindMode . If a port is not specified, a random port is chosen.

On success, the function returns true and the socket enters BoundState ; otherwise it returns false.

connectToHost(address, port[, mode=QIODeviceBase.OpenModeFlag.ReadWrite])
Parameters:

This is an overloaded function.

Attempts to make a connection to address on port port.

connectToHost(hostName, port[, mode=QIODeviceBase.OpenModeFlag.ReadWrite[, protocol=QAbstractSocket.NetworkLayerProtocol.AnyIPProtocol]])
Parameters:

Attempts to make a connection to hostName on the given port. The protocol parameter can be used to specify which network protocol to use (eg. IPv4 or IPv6).

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 errorOccurred() 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., “example.com”). QAbstractSocket will do a lookup only if required. port is in native byte order.

connected()

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

Note

On some operating systems the connected() signal may be directly emitted from the connectToHost() call for connections to the localhost.

See also

connectToHost() disconnected()

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()

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() abort()

error()
Return type:

SocketError

Returns the type of error that last occurred.

errorOccurred(arg__1)
Parameters:

arg__1 – SocketError

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

When this signal is emitted, the socket may not be ready for a reconnect attempt. In that case, attempts to reconnect should be done from the event loop. For example, use QChronoTimer::singleShot() with 0ns as the timeout.

SocketError is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType().

See also

error() errorString()Creating Custom Qt Types

flush()
Return type:

bool

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

waitForBytesWritten()

hostFound()

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

Note

Since Qt 4.6.3 QAbstractSocket may emit hostFound() directly from the connectToHost() call since a DNS result could have been cached.

See also

connected()

isValid()
Return type:

bool

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()
Return type:

QHostAddress

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

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

localPort()
Return type:

int

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

pauseMode()
Return type:

Combination of PauseMode

Returns the pause mode of this socket.

peerAddress()
Return type:

QHostAddress

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

peerName()
Return type:

str

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

peerPort()
Return type:

int

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

protocolTag()
Return type:

str

Returns the protocol tag for this socket. If the protocol tag is set then this is passed to QNetworkProxyQuery when this is created internally to indicate the protocol tag to be used.

proxy()
Return type:

QNetworkProxy

Returns the network proxy for this socket. By default DefaultProxy is used, which means this socket will query the default proxy settings for the application.

proxyAuthenticationRequired(proxy, authenticator)
Parameters:

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 QNetworkProxy

readBufferSize()
Return type:

int

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.

resume()

Continues data transfer on the socket. This method should only be used after the socket has been set to pause upon notifications and a notification has been received. The only notification currently supported is sslErrors() . Calling this method if the socket is not paused results in undefined behavior.

setLocalAddress(address)
Parameters:

address – QHostAddress

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., bind() ).

setLocalPort(port)
Parameters:

port – int

Sets the port on the local side of a connection to port.

You can call this function in a subclass of QAbstractSocket to change the return value of the localPort() 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 port of the socket prior to a connection (e.g., bind() ).

setPauseMode(pauseMode)
Parameters:

pauseMode – Combination of PauseMode

Controls whether to pause upon receiving a notification. The pauseMode parameter specifies the conditions in which the socket should be paused. The only notification currently supported is sslErrors() . If set to PauseOnSslErrors , data transfer on the socket will be paused and needs to be enabled explicitly again by calling resume() . By default this option is set to PauseNever . This option must be called before connecting to the server, otherwise it will result in undefined behavior.

setPeerAddress(address)
Parameters:

address – QHostAddress

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.

setPeerName(name)
Parameters:

name – str

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()

setPeerPort(port)
Parameters:

port – int

Sets the port of the remote side of the connection to port.

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

setProtocolTag(tag)
Parameters:

tag – str

Sets the protocol tag for this socket to tag.

See also

protocolTag()

setProxy(networkProxy)
Parameters:

networkProxy – QNetworkProxy

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Sets the explicit network proxy for this socket to networkProxy.

To disable the use of a proxy for this socket, use the NoProxy proxy type:

socket.setProxy(QNetworkProxy.NoProxy)

The default value for the proxy is DefaultProxy , which means the socket will use the application settings: if a proxy is set with setApplicationProxy , it will use that; otherwise, if a factory is set with setApplicationProxyFactory , it will query that factory with type TcpSocket .

setReadBufferSize(size)
Parameters:

size – int

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.

setSocketDescriptor(socketDescriptor[, state=QAbstractSocket.SocketState.ConnectedState[, openMode=QIODeviceBase.OpenModeFlag.ReadWrite]])
Parameters:
Return type:

bool

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. Read and write buffers are cleared, discarding any pending data.

Note

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

See also

socketDescriptor()

setSocketError(socketError)
Parameters:

socketError – SocketError

Sets the type of error that last occurred to socketError.

setSocketOption(option, value)
Parameters:

Sets the given option to the value described by value.

Note

Since the options are set on an internal socket the options only apply if the socket has been created. This is only guaranteed to have happened after a call to bind() , or when connected() has been emitted.

See also

socketOption()

setSocketState(state)
Parameters:

state – SocketState

Sets the state of the socket to state.

See also

state()

socketDescriptor()
Return type:

qintptr

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 .

socketOption(option)
Parameters:

option – SocketOption

Return type:

object

Returns the value of the option option.

socketType()
Return type:

SocketType

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

state()
Return type:

SocketState

Returns the state of the socket.

See also

error()

stateChanged(arg__1)
Parameters:

arg__1 – SocketState

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

SocketState is not a registered metatype, so for queued connections, you will have to register it with Q_DECLARE_METATYPE() and qRegisterMetaType().

See also

state() Creating Custom Qt Types

waitForConnected([msecs=30000])
Parameters:

msecs – int

Return type:

bool

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

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:

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.

Note

Multiple calls to this functions do not accumulate the time. If the function times out, the connecting process will be aborted.

Note

This function may fail randomly on Windows. Consider using the event loop and the connected() signal if your software will run on Windows.

See also

connectToHost() connected()

waitForDisconnected([msecs=30000])
Parameters:

msecs – int

Return type:

bool

Warning

This section contains snippets that were automatically translated from C++ to Python and may contain errors.

Waits until the socket has disconnected, up to msecs milliseconds. If the connection was successfully disconnected, this function returns true; otherwise it returns false (if the operation timed out, if an error occurred, or if this QAbstractSocket is already disconnected). 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:

socket.disconnectFromHost()
if (socket.state() == QAbstractSocket.UnconnectedState
    or socket.waitForDisconnected(1000)) {
        qDebug("Disconnected!")

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

Note

This function may fail randomly on Windows. Consider using the event loop and the disconnected() signal if your software will run on Windows.

See also

disconnectFromHost() close()