\inmodule QtCore More...

#include <qsettings.h>

Inheritance diagram for QSettings:

Collaboration diagram for QSettings:

Public Types
enum	Status { NoError = 0 , AccessError , FormatError }
	The following status values are possible: More...

enum	Format { NativeFormat = 0 , IniFormat = 1 , InvalidFormat = 16 , CustomFormat1 , CustomFormat2 , CustomFormat3 , CustomFormat4 , CustomFormat5 , CustomFormat6 , CustomFormat7 , CustomFormat8 , CustomFormat9 , CustomFormat10 , CustomFormat11 , CustomFormat12 , CustomFormat13 , CustomFormat14 , CustomFormat15 , CustomFormat16 }

enum	Scope { UserScope , SystemScope }

typedef QMap< QString, QVariant >	SettingsMap

typedef bool(*)	ReadFunc(QIODevice &device, SettingsMap &map)

typedef bool(*)	WriteFunc(QIODevice &device, const SettingsMap &map)

Public Member Functions
	QSettings (const QString &organization, const QString &application=QString(), QObject *parent=nullptr)

	QSettings (Scope scope, const QString &organization, const QString &application=QString(), QObject *parent=nullptr)

	QSettings (Format format, Scope scope, const QString &organization, const QString &application=QString(), QObject *parent=nullptr)

	QSettings (const QString &fileName, Format format, QObject *parent=nullptr)

	QSettings (QObject *parent=nullptr)

	QSettings (Scope scope, QObject *parent=nullptr)

	~QSettings ()

void	clear ()

void	sync ()

Status	status () const

bool	isAtomicSyncRequired () const

void	setAtomicSyncRequired (bool enable)

void	beginGroup (QAnyStringView prefix)

void	endGroup ()

QString	group () const

int	beginReadArray (QAnyStringView prefix)

void	beginWriteArray (QAnyStringView prefix, int size=-1)

void	endArray ()

void	setArrayIndex (int i)

QStringList	allKeys () const

QStringList	childKeys () const

QStringList	childGroups () const

bool	isWritable () const

void	setValue (QAnyStringView key, const QVariant &value)

QVariant	value (QAnyStringView key, const QVariant &defaultValue) const

QVariant	value (QAnyStringView key) const

void	remove (QAnyStringView key)

bool	contains (QAnyStringView key) const

void	setFallbacksEnabled (bool b)

bool	fallbacksEnabled () const

QString	fileName () const

Format	format () const

Scope	scope () const

QString	organizationName () const

QString	applicationName () const

Public Member Functions inherited from QObject
Q_INVOKABLE	QObject (QObject *parent=nullptr)
	Constructs an object with parent object parent.

virtual	~QObject ()
	Destroys the object, deleting all its child objects.

virtual bool	eventFilter (QObject watched, QEvent event)
	Filters events if this object has been installed as an event filter for the watched object.

QString	objectName () const

Q_WEAK_OVERLOAD void	setObjectName (const QString &name)
	Sets the object's name to name.

void	setObjectName (QAnyStringView name)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

QBindable< QString >	bindableObjectName ()

bool	isWidgetType () const
	Returns `true` if the object is a widget; otherwise returns `false`.

bool	isWindowType () const
	Returns `true` if the object is a window; otherwise returns `false`.

bool	isQuickItemType () const
	Returns `true` if the object is a QQuickItem; otherwise returns `false`.

bool	signalsBlocked () const noexcept
	Returns `true` if signals are blocked; otherwise returns `false`.

bool	blockSignals (bool b) noexcept
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it).

QThread *	thread () const
	Returns the thread in which the object lives.

bool	moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL)
	Changes the thread affinity for this object and its children and returns `true` on success.

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)
	This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds.

int	startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer)

void	killTimer (int id)
	Kills the timer with timer identifier, id.

void	killTimer (Qt::TimerId id)

template<typename T >
T	findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object.

template<typename T >
QList< T >	findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects.

template<typename T >
T	findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

template<typename T >
QList< T >	findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

const QObjectList &	children () const
	Returns a list of child objects.

void	setParent (QObject *parent)
	Makes the object a child of parent.

void	installEventFilter (QObject *filterObj)
	Installs an event filter filterObj on this object.

void	removeEventFilter (QObject *obj)
	Removes an event filter object obj from this object.

QMetaObject::Connection	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const

bool	disconnect (const char signal=nullptr, const QObject receiver=nullptr, const char *member=nullptr) const

bool	disconnect (const QObject receiver, const char member=nullptr) const

void	dumpObjectTree () const
	Dumps a tree of children to the debug output.

void	dumpObjectInfo () const
	Dumps information about signal connections, etc.

bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value.

bool	setProperty (const char *name, QVariant &&value)

QVariant	property (const char *name) const
	Returns the value of the object's name property.

QList< QByteArray >	dynamicPropertyNames () const

QBindingStorage *	bindingStorage ()

const QBindingStorage *	bindingStorage () const

QObject *	parent () const
	Returns a pointer to the parent object.

bool	inherits (const char *classname) const
	Returns `true` if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns `false`.

Static Public Member Functions
static void	setDefaultFormat (Format format)

static Format	defaultFormat ()

static void	setPath (Format format, Scope scope, const QString &path)

static Format	registerFormat (const QString &extension, ReadFunc readFunc, WriteFunc writeFunc, Qt::CaseSensitivity caseSensitivity=Qt::CaseSensitive)

Static Public Member Functions inherited from QObject
static QMetaObject::Connection	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)
	\threadsafe

static QMetaObject::Connection	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection)

template<typename Func1 , typename Func2 >
static QMetaObject::Connection	connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot)

static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)
	\threadsafe

static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)

static bool	disconnect (const QMetaObject::Connection &)
	Disconnect a connection.

template<typename Func1 , typename Func2 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object receiver, Func2 slot)

template<typename Func1 >
static bool	disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object sender, Func1 signal, const QObject receiver, void **zero)

Protected Member Functions
bool	event (QEvent *event) override
	This virtual function receives events to an object and should return true if the event e was recognized and processed.

Protected Member Functions inherited from QObject
QObject *	sender () const
	Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr.

int	senderSignalIndex () const

int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal.

bool	isSignalConnected (const QMetaMethod &signal) const

virtual void	timerEvent (QTimerEvent *event)
	This event handler can be reimplemented in a subclass to receive timer events for the object.

virtual void	childEvent (QChildEvent *event)
	This event handler can be reimplemented in a subclass to receive child events.

virtual void	customEvent (QEvent *event)
	This event handler can be reimplemented in a subclass to receive custom events.

virtual void	connectNotify (const QMetaMethod &signal)

virtual void	disconnectNotify (const QMetaMethod &signal)

	QObject (QObjectPrivate &dd, QObject *parent=nullptr)

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()
	\threadsafe

Signals inherited from QObject
void	destroyed (QObject *=nullptr)
	This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked.

void	objectNameChanged (const QString &objectName, QPrivateSignal)
	This signal is emitted after the object's name has been changed.

Protected Attributes inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Properties inherited from QObject
QString	objectName
	the name of this object

Related Symbols inherited from QObject
template< class T > T	qobject_cast (const QObject *object)
	Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr.

template< typename T > T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

template< typename T > QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

	QObjectList
	\macro Q_CLASSINFO(Name, Value)

Detailed Description

\inmodule QtCore

The QSettings class provides persistent platform-independent application settings.

\reentrant

Users normally expect an application to remember its settings (window sizes and positions, options, etc.) across sessions. This information is often stored in the system registry on Windows, and in property list files on \macos and iOS. On Unix systems, in the absence of a standard, many applications (including the KDE applications) use INI text files.

QSettings is an abstraction around these technologies, enabling you to save and restore application settings in a portable manner. It also supports \l{registerFormat()}{custom storage formats}.

QSettings's API is based on QVariant, allowing you to save most value-based types, such as QString, QRect, and QImage, with the minimum of effort.

If all you need is a non-persistent memory-based structure, consider using QMap<QString, QVariant> instead.

Definition at line 26 of file qsettings.h.

Member Typedef Documentation

◆ ReadFunc

bool(*) QSettings::ReadFunc(QIODevice &device, SettingsMap &map)

Definition at line 171 of file qsettings.h.

◆ SettingsMap

QMap<QString, QVariant> QSettings::SettingsMap

Definition at line 170 of file qsettings.h.

◆ WriteFunc

bool(*) QSettings::WriteFunc(QIODevice &device, const SettingsMap &map)

Definition at line 172 of file qsettings.h.

Member Enumeration Documentation

◆ Format

enum QSettings::Format

Enumerator
NativeFormat
IniFormat
InvalidFormat
CustomFormat1
CustomFormat2
CustomFormat3
CustomFormat4
CustomFormat5
CustomFormat6
CustomFormat7
CustomFormat8
CustomFormat9
CustomFormat10
CustomFormat11
CustomFormat12
CustomFormat13
CustomFormat14
CustomFormat15
CustomFormat16

Definition at line 48 of file qsettings.h.

◆ Scope

enum QSettings::Scope

Enumerator
UserScope
SystemScope

Definition at line 84 of file qsettings.h.

◆ Status

enum QSettings::Status

The following status values are possible:

\value NoError No error occurred. \value AccessError An access error occurred (e.g. trying to write to a read-only file). \value FormatError A format error occurred (e.g. loading a malformed INI file).

See also: status()

Enumerator
NoError
AccessError
FormatError

Definition at line 39 of file qsettings.h.

Constructor & Destructor Documentation

◆ QSettings() [1/6]

QSettings::QSettings	(	const QString &	organization,
		const QString &	application = QString(),
		QObject *	parent = nullptr )

explicit

◆ QSettings() [2/6]

QSettings::QSettings	(	Scope	scope,
		const QString &	organization,
		const QString &	application = QString(),
		QObject *	parent = nullptr )

◆ QSettings() [3/6]

QSettings::QSettings	(	Format	format,
		Scope	scope,
		const QString &	organization,
		const QString &	application = QString(),
		QObject *	parent = nullptr )

◆ QSettings() [4/6]

QSettings::QSettings	(	const QString &	fileName,
		Format	format,
		QObject *	parent = nullptr )

◆ QSettings() [5/6]

QSettings::QSettings ( QObject * parent = nullptr )

explicit

◆ QSettings() [6/6]

QSettings::QSettings	(	Scope	scope,
		QObject *	parent = nullptr )

explicit

◆ ~QSettings()

QSettings::~QSettings ( )

Member Function Documentation

◆ allKeys()

QStringList QSettings::allKeys ( ) const

◆ applicationName()

QString QSettings::applicationName ( ) const

◆ beginGroup()

void QSettings::beginGroup ( QAnyStringView prefix )

◆ beginReadArray()

int QSettings::beginReadArray ( QAnyStringView prefix )

◆ beginWriteArray()

void QSettings::beginWriteArray	(	QAnyStringView	prefix,
		int	size = -1 )

◆ childGroups()

QStringList QSettings::childGroups ( ) const

◆ childKeys()

QStringList QSettings::childKeys ( ) const

◆ clear()

void QSettings::clear ( )

◆ contains()

bool QSettings::contains ( QAnyStringView key ) const

◆ defaultFormat()

static Format QSettings::defaultFormat ( )

static

◆ endArray()

void QSettings::endArray ( )

◆ endGroup()

void QSettings::endGroup ( )

◆ event()

bool QSettings::event ( QEvent * e )

overrideprotectedvirtual

This virtual function receives events to an object and should return true if the event e was recognized and processed.

The event() function can be reimplemented to customize the behavior of an object.

Make sure you call the parent event class implementation for all the events you did not handle.

Example:

class MyClass : public QWidget
{
    Q_OBJECT
 
public:
    MyClass(QWidget *parent = nullptr);
    ~MyClass();
 
    bool event(QEvent* ev) override
    {
        if (ev->type() == QEvent::PolishRequest) {
            // overwrite handling of PolishRequest if any
            doThings();
            return true;
        } else  if (ev->type() == QEvent::Show) {
            // complement handling of Show if any
            doThings2();
            QWidget::event(ev);
            return true;
        }
        // Make sure the rest of events are handled
        return QWidget::event(ev);
    }
};

See also: installEventFilter(), timerEvent(), QCoreApplication::sendEvent(), QCoreApplication::postEvent()

Reimplemented from QObject.

◆ fallbacksEnabled()

bool QSettings::fallbacksEnabled ( ) const

◆ fileName()

QString QSettings::fileName ( ) const

◆ format()

Format QSettings::format ( ) const

◆ group()

QString QSettings::group ( ) const

◆ isAtomicSyncRequired()

bool QSettings::isAtomicSyncRequired ( ) const

◆ isWritable()

bool QSettings::isWritable ( ) const

◆ organizationName()

QString QSettings::organizationName ( ) const

◆ registerFormat()

static Format QSettings::registerFormat	(	const QString &	extension,
		ReadFunc	readFunc,
		WriteFunc	writeFunc,
		Qt::CaseSensitivity	caseSensitivity = Qt::CaseSensitive )

static

◆ remove()

void QSettings::remove ( QAnyStringView key )

◆ scope()

Scope QSettings::scope ( ) const

◆ setArrayIndex()

void QSettings::setArrayIndex ( int i )

◆ setAtomicSyncRequired()

void QSettings::setAtomicSyncRequired ( bool enable )

◆ setDefaultFormat()

static void QSettings::setDefaultFormat ( Format format )

static

◆ setFallbacksEnabled()

void QSettings::setFallbacksEnabled ( bool b )

◆ setPath()

static void QSettings::setPath	(	Format	format,
		Scope	scope,
		const QString &	path )

static

◆ setValue()

void QSettings::setValue	(	QAnyStringView	key,
		const QVariant &	value )

◆ status()

Status QSettings::status ( ) const

◆ sync()

void QSettings::sync ( )

◆ value() [1/2]

QVariant QSettings::value ( QAnyStringView key ) const

◆ value() [2/2]

QVariant QSettings::value	(	QAnyStringView	key,
		const QVariant &	defaultValue ) const

The documentation for this class was generated from the following file:

qtbase/src/corelib/io/qsettings.h (09f7408d034ef20a1e3551ede1ec4de774019abe)

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ ReadFunc

◆ SettingsMap

◆ WriteFunc

Member Enumeration Documentation

◆ Format

◆ Scope

◆ Status

Constructor & Destructor Documentation

◆ QSettings() [1/6]

◆ QSettings() [2/6]

◆ QSettings() [3/6]

◆ QSettings() [4/6]

◆ QSettings() [5/6]

◆ QSettings() [6/6]

◆ ~QSettings()

Member Function Documentation

◆ allKeys()

◆ applicationName()

◆ beginGroup()

◆ beginReadArray()

◆ beginWriteArray()

◆ childGroups()

◆ childKeys()

◆ clear()

◆ contains()

◆ defaultFormat()

◆ endArray()

◆ endGroup()

◆ event()

◆ fallbacksEnabled()

◆ fileName()

◆ format()

◆ group()

◆ isAtomicSyncRequired()

◆ isWritable()

◆ organizationName()

◆ registerFormat()

◆ remove()

◆ scope()

◆ setArrayIndex()

◆ setAtomicSyncRequired()

◆ setDefaultFormat()

◆ setFallbacksEnabled()

◆ setPath()

◆ setValue()

◆ status()

◆ sync()

◆ value() [1/2]

◆ value() [2/2]