- Qt 6.11
- Qt D-Bus
- C++ Classes
- QDBusInterface
- Qt 6.11.0 Reference Documentation

# QDBusInterface Class

The QDBusInterface class is a proxy for interfaces on remote objects. More...

Header: | `#include <QDBusInterface>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS DBus)` `target_link_libraries(mytarget PRIVATE Qt6::DBus)`
qmake: | `QT += dbus`
Inherits: | QDBusAbstractInterface

- List of all members, including inherited members

## Public Functions

| QDBusInterface(const QString &service, const QString &path, const QString &interface = QString(), const QDBusConnection &connection = QDBusConnection::sessionBus(), QObject *parent = nullptr)
virtual | ~QDBusInterface()

## Reimplemented Public Functions

virtual const QMetaObject * | metaObject() const override
virtual int | qt_metacall(QMetaObject::Call _c, int _id, void **_a) override
virtual void * | qt_metacast(const char *_clname) override

## Detailed Description

QDBusInterface is a generic accessor class that is used to place calls to remote objects, connect to signals exported by remote objects and get/set the value of remote properties. This class is useful for dynamic access to remote objects: that is, when you do not have a generated code that represents the remote interface.

Calls are usually placed by using the call() function, which constructs the message, sends it over the bus, waits for the reply and decodes the reply. Signals are connected to by using the normal QObject::connect() function. Finally, properties are accessed using the QObject::property() and QObject::setProperty() functions.

The following code snippet demonstrates how to perform a mathematical operation of `"2 + 2"` in a remote application called `com.example.Calculator`, accessed via the session bus.

     QDBusInterface remoteApp( "com.example.Calculator", "/Calculator/Operations",
                               "org.mathematics.RPNCalculator" );
     remoteApp.call( "PushOperand", 2 );
     remoteApp.call( "PushOperand", 2 );
     remoteApp.call( "ExecuteOperation", "+" );
     QDBusReply<int> reply = remoteApp.call( "PopOperand" );

     if ( reply.isValid() )
         printf( "%d", reply.value() );          // prints 4

See also Qt D-Bus XML compiler (qdbusxml2cpp).

## Member Function Documentation

### QDBusInterface::QDBusInterface(const QString &service, const QString &path, const QString &interface = QString(), const QDBusConnection &connection = QDBusConnection::sessionBus(), QObject *parent = nullptr)

Creates a dynamic QDBusInterface object associated with the interface interface on object at path path on service service, using the given connection. If interface is an empty string, the object created will refer to the merging of all interfaces found by introspecting that object. Otherwise if interface is not empty, the QDBusInterface object will be cached to speedup further creations of the same interface.

parent is passed to the base class constructor.

If the remote service service is not present or if an error occurs trying to obtain the description of the remote interface interface, the object created will not be valid (see isValid()).

### `[virtual noexcept]` QDBusInterface::~QDBusInterface()

Destroy the object interface and frees up any resource used.