Qt
Cross-platform GUI app framework.
Contents
Software that Uses Qt
Something something eating your own dog food. Listed in the official tools, but not listing it here doesn't feel right.
The closest thing to a standard C++ build system out there. The bundled GUI uses Qt.
The most popular documentation generator for C++, though it supports other languages as well. The bundled GUI uses Qt.
Secure your conversations so well, you'll raise the blood pressure of potential eavesdroppers. The desktop client uses Qt and is open source.
Tools
Official Tools
If you'd rather stick to Visual Studio, this add-in will let you do that.
Nobody seems to talk about this, but Qt also provides a way to write an installer for your application. Does not support creation of macOS disk images, app bundles, or Linux packages, so be mindful of that when considering your project's distribution.
Third-Party Tools
Powerful debugger and general inspection tool for Qt-built software. Lets you inspect and manipulate the QObject hierarchy, view object properties, edit widgets at runtime, and far, far more. A two-sentence blurb can't do it justice, seriously check it out.
Alternative implementation of moc that's binary-compatible with Qt's version.
Inspection tool with similar goals to GammaRay, though much simpler.
Bindings in Other Languages
Libraries
Integrations
OpenAL wrapper designed for games, with stb_vorbis and libsndfile support.
Add Font Awesome icons to your Qt application. Other icon sets are supported, too.
New Functionality
Cross-platform IRC framework. We've got enough IRC clients out there already, but I suppose this could also be used to implement a chat function in your application (e.g. for community support).
Binding for QML in C, primarily designed as an API for other languages to support QML.
Convert images from any Qt-supported format to OpenGL-format textures. Useful for speeding up texture loading in graphics applications.
Widget that lets you create and edit nodes in a graph similar to the kind provided by Unreal Engine, Substance Designer, or PureData.
Powerful set of libraries that provide GUI, logging, testing, configuration, and project functionality (among other things) for your application.
Create regular expressions using natural English expressions. Part of the VerbalExpressions project, which does the same thing for a wide variety of languages.
Software Repositories
Blogs
Talk about GammaRay and how it can help you dissect your Qt applications. Talk given at QtCon 2016 by Volker Krause.
I want to make my application do more than once thing at once. What could possibly go wrong? Talk given at QtCon 2016 by Giuseppe D'Angelo.
How to make your Qt application faster, Linux-style. Talk given at QtCon 2016 by Milian Wolff.
Talk about GammaRay and how it can help you dissect your Qt applications. Talk given at QtCon 2016 by Volker Krause.
KDAB
I want to make my application do more than once thing at once. What could possibly go wrong? Talk given at QtCon 2016 by Giuseppe D'Angelo.
How to make your Qt application faster, Linux-style. Talk given at QtCon 2016 by Milian Wolff.
Talk about GammaRay and how it can help you dissect your Qt applications. Talk given at QtCon 2016 by Volker Krause.
Books
Overview of advanced GUI programming techniques for those familiar (but not satisfied) with the basics. The source code used in the book is available for free.
Not your daddy's Qt. Tips and tricks for the experienced. The source code used in the book is available for free.
Free book that focuses on QML, named for this town in northeastern Spain that the authors vacationed to once.
Free book created by Qt Company. It provides you with a walk through of the different aspects of application development using the new Qt 6. It focuses on the Qt Quick technology, but also provides necessary information about writing C++ back-ends and extension for Qt Quick.
Other Relevant Awesome Lists
There's no reason you can't use C++ libraries that weren't designed for Qt. Sometimes they might even suit your needs better than what Qt offers.
Same goes for C libraries; might wanna brush up on those RAII techniques while you're at it.