qplugin.qdoc

Go to the documentation of this file.

// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
/*!
    \headerfile <QtPlugin>
    \inmodule QtCore
    \title Defining Plugins
    \keyword qtplugin-defining-plugins
    \ingroup plugins
 
    \brief The <QtPlugin> header file defines macros for defining plugins.
 
    \sa {How to Create Qt Plugins}
*/
 
/*!
    \macro Q_DECLARE_INTERFACE(ClassName, Identifier)
    \relates <QtPlugin>
 
    This macro associates the given \a Identifier (a string literal)
    to the interface class called \a ClassName. The \a Identifier must
    be unique.
 
    This macro is normally used right after the class definition for
    \a ClassName, in a header file.
 
    If you want to use Q_DECLARE_INTERFACE with interface classes
    declared in a namespace then you have to make sure the Q_DECLARE_INTERFACE
    is not inside a namespace though. For example:
    \snippet code/doc_src_qplugin.cpp 0
 
    \sa Q_INTERFACES(), {How to Create Qt Plugins}
*/
 
/*!
    \macro Q_PLUGIN_METADATA(...)
    \relates <QtPlugin>
    \since 5.0
 
    This macro is being used to declare meta data that is part of a plugin
    that instantiates this object.
 
    The macro needs to declare the IID of the interface implemented through
    the object, and reference a file containing the meta data for the plugin.
 
    There should be exactly one occurrence of this macro in the source code
    for a Qt plugin.
 
    Example:
 
    \snippet code/doc_src_qplugin.cpp 1
 
    Note that the class this macro appears on must be default-constructible.
 
    FILE is optional and points to a json file.
 
    The json file must reside in one of the include directories specified
    by the build-system.
    moc exits with an error when it could not find the specified file.
 
    \sa Q_DECLARE_INTERFACE(), {How to Create Qt Plugins}
*/
 
/*!
    \macro Q_IMPORT_PLUGIN(PluginName)
    \relates <QtPlugin>
 
    This macro imports the plugin named \a PluginName, which corresponds
    with the name of the class that declares metadata for the plugin with
    Q_PLUGIN_METADATA().
 
    Inserting this macro into your application's source code at file scope of
    the root namespace will allow you to make use of a static plugin.
 
    Example:
 
    \snippet code/doc_src_qplugin.cpp 2
 
    Static plugins must also be included by the linker when your
    application is built. See \l{Static Plugins} for more information
    on this.
 
    \sa {Static Plugins}, {How to Create Qt Plugins}
 
*/