QLocalServer Class

The QLocalServer class accepts connections from other processes on the same machine. More…

List of all members, including inherited members

Public Types

Public Functions

Signals

Static Public Members

Protected Functions

Detailed Description

Call listen() with a name, then fetch each new connection when newConnection() is emitted:

QLocalServer server;
server.listen("my-service");
QObject::connect(&server, &QLocalServer::newConnection, [&] {
    QLocalSocket *client = server.nextPendingConnection();
    client->write("hello");
});

If a previous process crashed without closing its server, listen() fails with an address-in-use error. Call removeServer() first to clear the stale socket file.

See also QLocalSocket.

Differences from Qt

Member Type Documentation

enum QLocalServer::SocketOption

Selects who may connect to the server.

typedef QLocalServer::SocketOptions

The SocketOptions type is a typedef for QFlags<SocketOption>. It stores an OR combination of SocketOption values.

Member Function Documentation

[explicit] QLocalServer::QLocalServer(QObject *parent = nullptr)

Constructs a local server with the given parent.

[override] QLocalServer::~QLocalServer()

Destroys the server and stops listening. Accepted sockets still pending are deleted with it.

void QLocalServer::close()

Stops listening and removes the socket file. Connections already accepted stay open.

See also listen().

QString QLocalServer::errorString() const

Returns a description of the last error.

See also serverError().

QString QLocalServer::fullServerName() const

Returns the path of the listening socket, or an empty string if not listening.

See also serverName().

[virtual] bool QLocalServer::hasPendingConnections() const

Returns true if a connection is waiting for nextPendingConnection().

[virtual, protected] void QLocalServer::incomingConnection(quintptr socketDescriptor)

Called for each accepted connection with its socketDescriptor. The default wraps it in a QLocalSocket and queues it for nextPendingConnection().

bool QLocalServer::isListening() const

Returns true if the server is listening.

See also listen().

bool QLocalServer::listen(const QString &name)

Starts listening on the socket name. A relative name is placed in QDir::tempPath(). Returns true on success.

See also close(), removeServer() and serverError().

int QLocalServer::maxPendingConnections() const

Returns the most connections held for nextPendingConnection().

See also setMaxPendingConnections().

[signal] void QLocalServer::newConnection()

This signal is emitted each time a new connection is available.

[virtual] QLocalSocket * QLocalServer::nextPendingConnection()

Returns the next pending connection, or nullptr if there is none. The socket is a child of the server until you reparent or delete it.

See also newConnection().

[static] bool QLocalServer::removeServer(const QString &name)

Removes the socket file for name, which clears the leftovers of a crashed server. Returns true if there is no longer such a file.

See also listen().

QLocalSocket::LocalSocketError QLocalServer::serverError() const

Returns the last error.

See also errorString().

QString QLocalServer::serverName() const

Returns the name given to listen(), or an empty string if not listening.

See also fullServerName().

void QLocalServer::setMaxPendingConnections(int numConnections)

Sets the most connections held for nextPendingConnection() to numConnections. Further clients wait in the system's queue.

See also maxPendingConnections().

void QLocalServer::setSocketOptions(SocketOptions options)

Sets the access options to options, which apply from the next listen().

See also socketOptions().

qintptr QLocalServer::socketDescriptor() const

Returns the native listening descriptor, or -1 if not listening.

SocketOptions QLocalServer::socketOptions() const

Returns the access options.

See also setSocketOptions().

bool QLocalServer::waitForNewConnection(int msec = 0, bool *timedOut = nullptr)

Waits up to msec milliseconds for a connection; a negative value waits forever. Returns true if one is pending. If timedOut is not null, it says whether the wait timed out.

See also hasPendingConnections().