- Qt 5.15
- Qt Core
- Qt Core C++ Classes
- Qt 5.15.19 Reference Documentation

# Qt Core C++ Classes

Provides core non-GUI functionality. More...

## Namespaces

Qt | Contains miscellaneous identifiers used throughout the Qt library

## 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
QAbstractState | The base class of states of a QStateMachine
QAbstractTableModel | Abstract model that can be subclassed to create table models
QAbstractTransition | The base class of transitions between QAbstractState objects
QAnimationGroup | Abstract base class for groups of animations
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
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
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
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
QEventTransition | QObject-specific transition for Qt events
QException | Base class for exceptions that can 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
QFinalState | Final state
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
QHistoryState | Means of returning to a previously active substate
QIODevice | The base interface class of all I/O devices in Qt
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
QJalaliCalendar | Jalali (Hijri Shamsi) calendar system implementation
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
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 lists
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 a red-black-tree-based dictionary
QMap::key_iterator | QMap::key_iterator class provides an STL-style const iterator for QMap and QMultiMap keys
QMapIterator | Java-style const iterator for QMap and QMultiMap
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
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
QMultiHash | Convenience QHash subclass that provides multi-valued hashes
QMultiMap | Convenience QMap subclass that provides multi-valued maps
QMutableHashIterator | Java-style non-const iterator for QHash and QMultiHash
QMutableListIterator | Java-style non-const iterator for QList and QQueue
QMutableMapIterator | Java-style non-const iterator for QMap and QMultiMap
QMutableSetIterator | Java-style non-const iterator for QSet
QMutableVectorIterator | Java-style non-const iterator for QVector and QStack
QMutex | Access serialization between threads
QMutexLocker | Convenience class that simplifies locking and unlocking mutexes
QObject | The base class of all Qt objects
QObjectCleanupHandler | Watches the lifetime of multiple QObjects
QOperatingSystemVersion | Information about the operating system version
QPair | Template class that stores a pair of items
QParallelAnimationGroup | Parallel group of animations
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
QPropertyAnimation | Animates Qt properties
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 rectangle in the plane using floating point precision
QRecursiveMutex | Access serialization between threads
QRegExp | Pattern matching using regular expressions
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
QSignalTransition | Transition based on a Qt signal
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
QState | General-purpose state for QStateMachine
QStateMachine | Hierarchical finite state machine
QStateMachine::SignalEvent | Represents a Qt signal event
QStateMachine::WrappedEvent | Inherits QEvent and holds a clone of an event associated with a QObject
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
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
QStringRef | Thin wrapper around QString substrings
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
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
QTextCodec | Conversions between text encodings
QTextDecoder | State-based decoder
QTextEncoder | State-based encoder
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
QUnhandledException | UnhandledException class represents an unhandled exception in a worker thread
QUrl | Convenient interface for working with URLs
QUrlQuery | Way to manipulate a key-value pairs in a URL's query
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
QVector | Template class that provides a dynamic array
QVectorIterator | Java-style const iterator for QVector and QStack
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.