Qt Core C++ Classes

Provides core non-GUI functionality. More...

Namespaces

Qt

Contains miscellaneous identifiers used throughout the Qt library

QtAndroidPrivate

QtAndroid namespace provides miscellaneous functions to aid Android development

QtFuture

Contains miscellaneous identifiers used by the QFuture class

QtLiterals

Declares literal operators for Qt types

Classes

QAbstractAnimation

The base of all animations

QAbstractEventDispatcher

Interface to manage Qt's event queue

QAbstractEventDispatcher::TimerInfo

QAbstractItemModel

The abstract interface for item model classes

QAbstractListModel

Abstract model that can be subclassed to create one-dimensional list models

QAbstractNativeEventFilter

Interface for receiving native events, such as MSG or XCB event structs

QAbstractProxyModel

Base class for proxy item models that can do sorting, filtering or other data processing tasks

QAbstractTableModel

Abstract model that can be subclassed to create table models

QAdoptSharedDataTag

Helper tag class

QAndroidActivityResultReceiver

Interface used for callbacks from onActivityResult() in the main Android activity

QAndroidBinder

Wraps the most important methods of Android Binder class

QAndroidIntent

Wraps the most important methods of Android Intent class

QAndroidParcel

Wraps the most important methods of Android Parcel class

QAndroidService

Wraps the most important methods of Android Service class

QAndroidServiceConnection

Wraps the most important methods of Android ServiceConnection class

QAnimationGroup

Abstract base class for groups of animations

QAnyStringView

Unified view on Latin-1, UTF-8, or UTF-16 strings with a read-only subset of the QString API

QAssociativeIterable

Iterable interface for an associative container in a QVariant

QAtomicInt

Platform-independent atomic operations on int

QAtomicInteger

Platform-independent atomic operations on integers

QAtomicPointer

Template class that provides platform-independent atomic operations on pointers

QBEInteger

Platform-independent big-endian integers

QBasicTimer

Timer events for objects

QBindable

Wrapper class around binding-enabled properties. It allows type-safe operations while abstracting the differences between the various property classes away

QBitArray

Array of bits

QBuffer

QIODevice interface for a QByteArray

QByteArray

Array of bytes

QByteArray::FromBase64Result

QByteArray::FromBase64Result class holds the result of a call to QByteArray::fromBase64Encoding

QByteArrayList

List of byte arrays

QByteArrayMatcher

Holds a sequence of bytes that can be quickly matched in a byte array

QByteArrayView

View on an array of bytes with a read-only subset of the QByteArray API

QCache

Template class that provides a cache

QCalendar

Describes calendar systems

QCborArray

Used to hold an array of CBOR elements

QCborError

Holds the error condition found while parsing or validating a CBOR stream

QCborMap

Used to hold an associative container representable in CBOR

QCborMap::ConstIterator

QCborMap::ConstIterator class provides an STL-style const iterator for QCborMap

QCborMap::Iterator

QCborMap::Iterator class provides an STL-style non-const iterator for QCborMap

QCborParserError

Used by QCborValue to report a parsing error

QCborStreamReader

Simple CBOR stream decoder, operating on either a QByteArray or QIODevice

QCborStreamReader::StringResult

QCborStreamWriter

Simple CBOR encoder operating on a one-way stream

QCborValue

Encapsulates a value in CBOR

QChar

16-bit Unicode character

QChildEvent

Contains event parameters for child object events

QCollator

Compares strings according to a localized collation algorithm

QCollatorSortKey

Can be used to speed up string collation

QCommandLineOption

Defines a possible command-line option

QCommandLineParser

Means for handling the command line options

QConcatenateTablesProxyModel

Proxies multiple source models, concatenating their rows

QConstIterator

Allows iteration over a container in a QVariant

QContiguousCache

Template class that provides a contiguous cache

QCoreApplication

Event loop for Qt applications without UI

QCryptographicHash

Way to generate cryptographic hashes

QDataStream

Serialization of binary data to a QIODevice

QDate

Date functions

QDateTime

Date and time functions

QDeadlineTimer

Marks a deadline in the future

QDebug

Output stream for debugging information

QDebugStateSaver

Convenience class for custom QDebug operators

QDir

Access to directory structures and their contents

QDirIterator

Iterator for directory entrylists

QDynamicPropertyChangeEvent

Contains event parameters for dynamic property change events

QEasingCurve

Easing curves for controlling animation

QElapsedTimer

Fast way to calculate elapsed times

QEnableSharedFromThis

A base class that allows obtaining a QSharedPointer for an object already managed by a shared pointer

QEvent

The base class of all event classes. Event objects contain event parameters

QEventLoop

Means of entering and leaving an event loop

QEventLoopLocker

Means to quit an event loop when it is no longer needed

QException

Base class for exceptions that can be transferred across threads

QExplicitlySharedDataPointer

Represents a pointer to an explicitly shared object

QFile

Interface for reading from and writing to files

QFileDevice

Interface for reading from and writing to open files

QFileInfo

System-independent file information

QFileSelector

Convenient way of selecting file variants

QFileSystemWatcher

Interface for monitoring files and directories for modifications

QFlag

Helper data type for QFlags

QFlags

Type-safe way of storing OR-combinations of enum values

QFuture

Represents the result of an asynchronous computation

QFutureIterator

Java-style const iterator for QFuture

QFutureSynchronizer

Convenience class that simplifies QFuture synchronization

QFutureWatcher

Allows monitoring a QFuture using signals and slots

QGenericArgument

Internal helper class for marshalling arguments

QGenericReturnArgument

Internal helper class for marshalling arguments

QGlobalStatic

Used to implement a global static object

QGregorianCalendar

Implements the Gregorian calendar

QHash

Template class that provides a hash-table-based dictionary

QHashIterator

Java-style const iterator for QHash and QMultiHash

QIODevice

The base interface class of all I/O devices in Qt

QIODeviceBase

Base class for QIODevice that provides flags describing the mode in which a device is opened

QIdentityProxyModel

Proxies its source model unmodified

QItemSelection

Manages information about selected items in a model

QItemSelectionModel

Keeps track of a view's selected items

QItemSelectionRange

Manages information about a range of selected items in a model

QIterable

Template class that is the base class for QSequentialIterable and QAssociativeIterable

QIterator

Template class that allows iteration over a container in a QVariant

QJalaliCalendar

Jalali (Hijri Shamsi) calendar system implementation

QJniEnvironment

Access to the JNI Environment (JNIEnv)

QJniObject

A convenience wrapper around the Java Native Interface (JNI)

QJsonArray

Encapsulates a JSON array

QJsonDocument

Way to read and write JSON documents

QJsonObject

Encapsulates a JSON object

QJsonParseError

Used to report errors during JSON parsing

QJsonValue

Encapsulates a value in JSON

QJulianCalendar

Julian calendar system implementation

QKeyCombination

Stores a combination of a key with optional modifiers

QKeyValueIterator

Iterator over the key/value pairs of an associative container

QLEInteger

Platform-independent little-endian integers

QLatin1Char

8-bit ASCII/Latin-1 character

QLatin1String

Thin wrapper around an US-ASCII/Latin-1 encoded string literal

QLibrary

Loads shared libraries at runtime

QLibraryInfo

Information about the Qt library

QLine

Two-dimensional vector using integer precision

QLineF

Two-dimensional vector using floating point precision

QList

Template class that provides a dynamic array

QListIterator

Java-style const iterator for QList and QQueue

QLocale

Converts between numbers and their string representations in various languages

QLockFile

Locking between processes using a file

QLoggingCategory

Represents a category, or 'area' in the logging infrastructure

QMap

Template class that provides an associative array

QMapIterator

Java-style const iterator for QMap

QMargins

Defines the four margins of a rectangle

QMarginsF

Defines the four margins of a rectangle

QMessageAuthenticationCode

Way to generate hash-based message authentication codes

QMessageLogContext

Additional information about a log message

QMessageLogger

Generates log messages

QMetaClassInfo

Additional information about a class

QMetaEnum

Meta-data about an enumerator

QMetaMethod

Meta-data about a member function

QMetaObject

Contains meta-information about Qt objects

QMetaObject::Connection

QMetaProperty

Meta-data about a property

QMetaSequence

Allows type erased access to sequential containers

QMetaType

Manages named types in the meta-object system

QMilankovicCalendar

Milanković calendar system implementation

QMimeData

Container for data that records information about its MIME type

QMimeDatabase

Maintains a database of MIME types

QMimeType

Describes types of file or data, represented by a MIME type string

QModelIndex

Used to locate data in a data model

QModelRoleData

Holds a role and the data associated to that role

QModelRoleDataSpan

Span over QModelRoleData objects

QMultiHash

Convenience QHash subclass that provides multi-valued hashes

QMultiMap

Template class that provides an associative array with multiple equivalent keys

QMultiMap::key_iterator

QMultiMap::key_iterator class provides an STL-style const iterator for QMultiMap keys

QMultiMapIterator

Java-style const iterator for QMultiMap. QMultiMap has both Java-style iterators and STL-style iterators. STL-style iterators are more efficient and should be preferred

QMutableHashIterator

Java-style non-const iterator for QHash and QMultiHash

QMutableListIterator

Java-style non-const iterator for QList, QQueue and QStack

QMutableMapIterator

Java-style non-const iterator for QMap

QMutableMultiMapIterator

Java-style non-const iterator for QMultiMap

QMutableSetIterator

Java-style non-const iterator for QSet

QMutex

Access serialization between threads

QMutexLocker

Convenience class that simplifies locking and unlocking mutexes

QNativeInterface::QAndroidApplication

Native interface to a core application on Android

QObject

The base class of all Qt objects

QObjectBindableProperty

Template class that enables automatic property bindings for property data stored in QObject derived classes

QObjectCleanupHandler

Watches the lifetime of multiple QObjects

QOperatingSystemVersion

Information about the operating system version

QParallelAnimationGroup

Parallel group of animations

QPartialOrdering

Represents the result of a comparison that allows for unordered results

QPauseAnimation

Pause for QSequentialAnimationGroup

QPersistentModelIndex

Used to locate data in a data model

QPluginLoader

Loads a plugin at run-time

QPoint

Defines a point in the plane using integer precision

QPointF

Defines a point in the plane using floating point precision

QPointer

Template class that provides guarded pointers to QObject

QProcess

Used to start external programs and to communicate with them

QProcess::CreateProcessArguments

QProcessEnvironment

Holds the environment variables that can be passed to a program

QPromise

Way to store computation results to be accessed by QFuture

QProperty

Template class that enables automatic property bindings

QPropertyAnimation

Animates Qt properties

QPropertyBindingError

QPropertyChangeHandler

Controls the lifecycle of change callback installed on a QProperty

QPropertyData

Helper class for properties with automatic property bindings

QPropertyNotifier

Controls the lifecycle of change callback installed on a QProperty

QQueue

Generic container that provides a queue

QRandomGenerator

Allows one to obtain random values from a high-quality Random Number Generator

QRandomGenerator64

Allows one to obtain 64-bit random values from a high-quality, seed-less Random Number Generator

QReadLocker

Convenience class that simplifies locking and unlocking read-write locks for read access

QReadWriteLock

Read-write locking

QRect

Defines a rectangle in the plane using integer precision

QRectF

Defines a finite rectangle in the plane using floating point precision

QRecursiveMutex

Access serialization between threads

QRegularExpression

Pattern matching using regular expressions

QRegularExpressionMatch

The results of a matching a QRegularExpression against a string

QRegularExpressionMatchIterator

Iterator on the results of a global match of a QRegularExpression object against a string

QResource

Interface for reading directly from resources

QRomanCalendar

Shared base for calendars based on the ancient Roman calendar

QRunnable

The base class for all runnable objects

QSaveFile

Interface for safely writing to files

QScopeGuard

Provides a scope guard for calling a function at the end of a scope

QScopedArrayPointer

Stores a pointer to a dynamically allocated array of objects, and deletes it upon destruction

QScopedPointer

Stores a pointer to a dynamically allocated object, and deletes it upon destruction

QScopedValueRollback

Resets a variable to its previous value on destruction

QSemaphore

General counting semaphore

QSemaphoreReleaser

Exception-safe deferral of a QSemaphore::release() call

QSequentialAnimationGroup

Sequential group of animations

QSequentialIterable

Iterable interface for a container in a QVariant

QSet

Template class that provides a hash-table-based set

QSet::const_iterator

QSet::const_iterator class provides an STL-style const iterator for QSet

QSet::iterator

QSet::iterator class provides an STL-style non-const iterator for QSet

QSetIterator

Java-style const iterator for QSet

QSettings

Persistent platform-independent application settings

QSharedData

Base class for shared data objects

QSharedDataPointer

Represents a pointer to an implicitly shared object

QSharedMemory

Access to a shared memory segment

QSharedPointer

Holds a strong reference to a shared pointer

QSignalBlocker

Exception-safe wrapper around QObject::blockSignals()

QSignalMapper

Bundles signals from identifiable senders

QSize

Defines the size of a two-dimensional object using integer point precision

QSizeF

Defines the size of a two-dimensional object using floating point precision

QSocketNotifier

Support for monitoring activity on a file descriptor

QSortFilterProxyModel

Support for sorting and filtering data passed between another model and a view

QStack

Template class that provides a stack

QStandardPaths

Methods for accessing standard paths

QStaticByteArrayMatcher

Compile-time version of QByteArrayMatcher

QStaticPlugin

Struct containing a reference to a static plugin instance together with its meta data

QStorageInfo

Provides information about currently mounted storage and drives

QString

Unicode character string

QStringConverter

Base class for encoding and decoding text

QStringDecoder

State-based decoder for text

QStringEncoder

State-based encoder for text

QStringList

List of strings

QStringListModel

Model that supplies strings to views

QStringMatcher

Holds a sequence of characters that can be quickly matched in a Unicode string

QStringTokenizer

Splits strings into tokens along given separators

QStringView

Unified view on UTF-16 strings with a read-only subset of the QString API

QSysInfo

Information about the system

QSystemSemaphore

General counting system semaphore

QTaggedIterator

Template class that wraps an iterator and exposes standard iterator traits

QTemporaryDir

Creates a unique directory for temporary use

QTemporaryFile

I/O device that operates on temporary files

QTextBoundaryFinder

Way of finding Unicode text boundaries in a string

QTextStream

Convenient interface for reading and writing text

QThread

Platform-independent way to manage threads

QThreadPool

Manages a collection of QThreads

QThreadStorage

Per-thread data storage

QTime

Clock time functions

QTimeLine

Timeline for controlling animations

QTimeZone

Converts between UTC and local time in a specific time zone

QTimeZone::OffsetData

QTimer

Repetitive and single-shot timers

QTimerEvent

Contains parameters that describe a timer event

QTranslator

Internationalization support for text output

QTypeRevision

Contains a lightweight representation of a version number with two 8-bit segments, major and minor, either of which can be unknown

QUnhandledException

Represents an unhandled exception in a Qt Concurrent worker thread

QUntypedBindable

Uniform interface over bindable properties like QProperty\<T\> and QObjectBindableProperty of any type T

QUrl

Convenient interface for working with URLs

QUrlQuery

Way to manipulate a key-value pairs in a URL's query

QUtf8StringView

Unified view on UTF-8 strings with a read-only subset of the QString API

QUuid

Stores a Universally Unique Identifier (UUID)

QVarLengthArray

Low-level variable-length array

QVariant

Acts like a union for the most common Qt data types

QVariantAnimation

Base class for animations

QVariantConstPointer

Emulated const pointer to QVariant based on a pointer

QVariantPointer

Template class that emulates a pointer to QVariant based on a pointer

QVariantRef

Acts as a non-const reference to a QVariant

QVector

Alias for QList

QVersionNumber

Contains a version number with an arbitrary number of segments

QWaitCondition

Condition variable for synchronizing threads

QWeakPointer

Holds a weak reference to a shared pointer

QWinEventNotifier

Support for the Windows Wait functions

QWriteLocker

Convenience class that simplifies locking and unlocking read-write locks for write access

QXmlStreamAttribute

Represents a single XML attribute

QXmlStreamAttributes

Represents a vector of QXmlStreamAttribute

QXmlStreamEntityDeclaration

Represents a DTD entity declaration

QXmlStreamEntityResolver

Entity resolver for a QXmlStreamReader

QXmlStreamNamespaceDeclaration

Represents a namespace declaration

QXmlStreamNotationDeclaration

Represents a DTD notation declaration

QXmlStreamReader

Fast parser for reading well-formed XML via a simple streaming API

QXmlStreamWriter

XML writer with a simple streaming API

qfloat16

Provides 16-bit floating point support

Detailed Description

All other Qt modules rely on this module.

The Qt Core page contains information about how to use the module.

© 2021 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.