Qt Core

Using a Qt module's C++ API requires linking against the module library, either directly or through other dependencies. Several build tools have dedicated support for this, including CMake and qmake.

Building with CMake▲

find_package(Qt6 REQUIRED COMPONENTS Core)
target_link_libraries(mytarget PRIVATE Qt6::Core)

Building with qmake▲

Qt provides thread support in the form of platform-independent threading classes, a thread-safe way of posting events, and signal-slot connections across threads. Multithreaded programming is also a useful paradigm for performing time-consuming operations without freezing the user interface of an application.

The Thread Support in Qt page contains information on implementing threads in applications. Additional concurrent classes are provided by the Qt Concurrent module.

Qt provides a resource system for organizing application files and assets, a set of containers, and classes for receiving input and printing output.

• Container Classes

• Serializing Qt Data Types

• Implicit Sharing

In addition, Qt Core provides a platform-independent mechanism for storing binary files in the application's executable.

• The Qt Resource System

Qt Core also provides some of Qt's key frameworks.

• The Animation Framework

• JSON Support in Qt

• CBOR Support in Qt

• How to Create Qt Plugins

• The Event System

• Application Permissions

• C++ Classes

  • Animation Classes

  • Threading Classes

  • Container Classes

  • Plugin Classes

  • Implicitly Shared Classes

  • Input/Output Classes

  • Event Classes

• CMake API

  • CMake Commands

  • CMake Variables

  • CMake Target Properties

Changes to Qt Core lists important changes in the module API and functionality that were made for the Qt 6 series of Qt.

Qt Core is available under commercial licenses from The Qt Company. In addition, it is available under free software licenses: The GNU Lesser General Public License, version 3, or the GNU General Public License, version 2. See Qt Licensing for further details.

Executables on Windows potentially link against The QtEntryPoint Library. This library is available under commercial licenses and also under the BSD 3-clause "New" or "Revised" License.

Furthermore, Qt Core in Qt 6.5.3 may contain third party modules under the following permissive licenses:

• BLAKE2 (reference implementation), version 54f4faa4c16ea34bcd59d16e8da46a64b259fc07: Creative Commons Zero v1.0 Universal or Apache License 2.0

• Data Compression Library (zlib), version 1.3: zlib License

• Easing Equations by Robert Penner: BSD 3-clause "New" or "Revised" License

• Efficient Binary-Decimal and Decimal-Binary Conversion Routines for IEEE Doubles, version 3.3.0: BSD 3-clause "New" or "Revised" License

• KWin, version 5.13.4: BSD-3-Clause

• MD4: Public Domain

• MD5: Public Domain

• PCRE2 - Stack-less Just-In-Time Compiler, version 10.42: BSD 2-clause "Simplified" License

• PCRE2, version 10.42: BSD 3-clause "New" or "Revised" License with PCRE2 binary-like Packages Exception

• QEventDispatcher on macOS: BSD 3-clause "New" or "Revised" License

• Secure Hash Algorithm SHA-1: Public Domain

• Secure Hash Algorithm SHA-3 - Keccak, version 3.2: Creative Commons Zero v1.0 Universal

• Secure Hash Algorithm SHA-3 - brg_endian, version https://github.com/BrianGladman/sha/ commit 4b9e13ead2c5b5e41ca27c65de4dd69ae0bac228: BSD 2-clause "Simplified" License

• Secure Hash Algorithms SHA-384 and SHA-512: BSD 3-clause "New" or "Revised" License

• SipHash Algorithm: Creative Commons Zero v1.0 Universal

• TinyCBOR, version 0.6.0: MIT License

• Unicode Character Database (UCD), version 30: Unicode License Agreement - Data Files and Software (2016)

• Unicode Common Locale Data Repository (CLDR), version v43: Unicode License Agreement - Data Files and Software (2016)

• extra-cmake-modules, version 5.84.0: BSD-3-Clause

• forkfd: MIT License