- Qt 5.3
- Qt Licensing
- Qt 5.3.2 Reference Documentation

# Qt Licensing

Qt is available under three different licensing options designed to accommodate the needs of our various users.

Qt licensed under our commercial license agreement is appropriate for development of proprietary/commercial software where you do not want to share any source code with third parties or otherwise cannot comply with the terms of the GNU LGPL version 2.1 or GNU GPL version 3.0.

Qt licensed under the GNU Lesser General Public License (LGPL) version 2.1 is appropriate for the development of Qt applications provided you can comply with the terms and conditions of the GNU LGPL version 2.1.

Qt licensed under the GNU General Public License (GPL) version 3.0 is appropriate for the development of Qt applications where you wish to use such applications in combination with software subject to the terms of the GNU GPL version 3.0 or where you are otherwise willing to comply with the terms of the GNU GPL version 3.0.

Qt documentation is licensed under the terms of the GNU Free Documentation License (FDL) version 1.3, as published by the Free Software Foundation. Alternatively, you may use the documentation in accordance with the terms contained in a written agreement between you and Digia.

Please see http://qt.digia.com/licensing for an overview of Qt licensing.

## Purchasing and Sales Information

To purchase or further information and assistance about Qt commercial licensing, please contact Digia Qt sales via one of the following channels:

Web: | http://qt.digia.com/contact-us
Phone, U.S. office (for sales in North America): | +1 408 433 9320
Phone, Norway office (for sales in the rest of the world): | +47 2108 0420

## Licenses Used in Qt

The following table lists the other licenses used in Qt, not provided under the GNU General Public License (GPL), GNU Lesser General Public License (LGPL) or the Qt Commercial License. Third-party licenses used in libraries that are supplied alongside Qt modules are also listed.

Note: Cross-module dependencies are also described on a general level. All Qt modules depend on Qt Core.

Qt Module/Tool | Component | Description | License Type | Notes
--- | --- | --- | --- | ---
Qt Core
QCrashHandler | Parts of implementation of QCrashHandler class. | BSD-style |
QUrl | Implementation of QUrl::fromUserInput(). | Modified BSD |
Cocoa Platform Plugin | Specific parts of the Qt for Mac OS X Cocoa port. | BSD-style | Qt for Mac OS X
qtmain library | A helper library for writing a cross-platform main() function on Windows. | Modified BSD | Qt for Windows
DES | Implementation of DES encryption (des.cpp). | MIT |
Shift-JIS Text Codec | A character encoding for Japanese. | BSD-style |
ISO-2022-JP (JIS) Text Codec | A widely used encoding for Japanese. | BSD-style |
EUC-JP Text Codec | EUC-JP is a variable-width encoding used to represent the elements of three Japanese character set standards. | BSD-style |
EUC-KR TextCodec | Extended Unix Code (EUC) is a multibyte character encoding system used primarily for Japanese, Korean, and simplified Chinese. | BSD-style |
GBK Text Codec | GBK is an extension of the GB2312 character set for simplified Chinese characters, used mainland China. | BSD-style |
Big5 Text Codec | Big5, or BIG-5, is a Chinese character encoding method used for Traditional Chinese characters. | BSD-style |
TSCII Text Codec | The TSCII codec provides conversion to and from the Tamil TSCII encoding. | BSD-style |
Stack-less Just-In-Time compiler | A platform-independent JIT compiler. | BSD |
Parts of the codecs implemented by Qt |  | BSD |
Unicode | Unicode character data. | Permissive, GPL-compatible |
Macros for building Qt files | Macros used in CMake files for building Qt. | BSD |
The PCRE library | The PCRE library is a set of functions that implement regular expression pattern matching using the same syntax and semantics as Perl 5. | BSD-style |
Third-party Licenses
Android C++ Run-time | GNU C++ run-time library (libstdc++) for Android. | GPLv3 with exception | Qt for Android
MD4 | implements the MD4 message-digest algorithm. | BSD |
MD5 | implements the MD5 message-digest algorithm. | BSD |
SHA-1 | implements the SHA-1 encryption algorithm. | BSD |
SHA-3 | implements the SHA-3 encryption algorithm. | BSD |
zlib | zlib is a general purpose data compression library. | BSD-style |
Qt Gui
QKeyMapper | Internal class for key mapping. | Custom, BSD-style | Qt for Linux/X11
Third-party Licenses
FreeType | Parts of FreeType project used in font rendering. | GPLv2, FreeType Project License |
Third-party Licenses
HarfBuzz | OpenType layout engine. | BSD-style |
FreeType 2 | Parts of FreeType project used in font rendering. | GPLv2, FreeType Project License |
PNG Reference Library | A library for reducing the time and effort it takes to support the PNG format. | BSD-style |
Pixman | Pixman is a library that provides low-level pixel manipulation features such as image compositing and trapezoid rasterization. | BSD-style |
Drag and Drop | Allows users to transfer information between and within applications. | BSD-style |
ANGLE | Opensource project to map OpenGL ES API calls to DirectX API. | BSD-style | Qt for Windows
Qt Location
Third-party Licenses
Poly2Tri | Poly2Tri is a sweepline constrained Delaunay Polygon Triangulation Library. | BSD-style |
Qt Network
Third-party Licenses
The Public Suffix List | A list of all known public Internet suffixes. | Mozilla Public License |
Qt Multimedia
Third-party Licenses
FFTReal | Fast Fourier transform of real-valued arrays. | LGPL | (Used in example code).
Qt SVG
Qt SVG License Information | Parts of code for arc handling in Qt SVG module. | BSD-style | Depends on Qt Gui, Qt Widgets
Qt Quick
Third-party Licenses
Easing Equations | Easing Equations is a collection of swappable functions that add flavor to motion. | BSD-style | Depends on Qt QML, Qt Gui, Qt Network
Qt Script |  |  | (Provided for Qt 4 compatibility) |
V8 benchmark tests | V8 benchmark tests used in Qt Script. | BSD-style |
Sunspider benchmark tests | Sunspider benchmark tests used in Qt Script. | BSD-style |
Third-party Licenses
JavaScriptCore |  | BSD-style |
Qt Test
Testlib | Parts of implementation of Qt Test library. | BSD, MIT |
Third-party Licenses
Valgrind | A code analysis tool for detecting memory leaks. | GPL v2 |
valgrind.h specific license |  | BSD-style |
Callgrind | A performance profiling tool. | GPL v2 |
Qt Print Support |  |  | Depends on Qt Gui and Qt Widgets |
PDF Licensing | Notes about PDF Licensing. |  |
Qt WebKit
WebKit used by the QtWebKit module | Parts of WebKit used by the QtWebKit module | BSD-style | Depends on Qt Gui, Qt Network, Qt SQL, Qt QML, and Qt Quick
Third-party Licenses
WebCore | A layout, rendering, and Document Object Model (DOM) library for HTML and SVG. | LGPL, MIT, BSD-style |
Qt Designer
Qt Designer License Information | Implementation of the recursive shadow casting algorithm in Qt Designer. | BSD (MIT) |
Qt Creator
Third-party Licenses
Botan | A C++ crypto library used in Qt Creator. | BSD |
Qt Image Formats
Third-party Licenses
TIFF | libtiff is a set of C functions (a library) that support the manipulation of TIFF image files. | BSD |
MNG | Support decoding and displaying of MNG format image files. | BSD-style |
Qt SQL
SQLite | A C library that implements a self-contained, embeddable, zero-configuration SQL database engine. | BSD-style |
Qt XML Patterns
Bison Parser | Bison is a parser generator. | GPL with exception | Depends on Qt Network
Plugins
JPEG | C software to implement JPEG image compression and decompression. | BSD-style |
IAccessible2 | An accessibility API for Microsoft Windows applications. | BSD | Qt for Windows
Cycle | A CPU tick counter. | MIT |
callgrind.h specific license |  | BSD-style |
xcb | A C language binding for the X Window System. | BSD-style | Qt for Linux/X11
at-spi and at-spi2 | A toolkit-neutral way of providing accessibility facilities in application. | LGPL | Qt for Linux/X11
xkbcommon | Keymap handling library for toolkits and window systems. | BSD-style | Qt for Linux/X11
Qt Tools
Third-party Licenses
Clucene Core Library | A high-performance, full-featured text search engine written in C++. | LGPL/Apache |

## Additional information

The documents below list related documents, such as information about Trademark and other licenses used in parts of Qt.

Notes about PDF Licensing | Details of restrictions on the use of PDF-related trademarks.
Qt SVG License Information | License information for Qt SVG
Third-Party Licenses Used in Qt | License information for third-party libraries supplied with Qt.
Android GNU C++ Run-time Licensing | Provides additional information about the licensing of run-time dependencies of Qt for Android
Licenses for Fonts Used in Qt for Embedded Linux | Information about the licenses of fonts supplied with Qt
Open Source Licensing of Qt | Information about open source licensing of Qt.
Trademarks | Information about trademarks owned by Digia and other organisations.
The qtmain Library | Describes the use and license of the qtmain helper library.
Contributions to the Cocoa Platform Plugin Files | License information for contributions by Apple, Inc. to specific parts of the Qt for Mac OS X Cocoa port.