GammaRay 2.11.2 We have released version 2.11.2 of our Qt application introspection tool GammaRay, bringing support for Qt 5.15 and improved Qt Quick item picking. GammaRay is a software introspection tool for Qt applications developed by KDAB. Leveraging the QObject introspection mechanism it allows you to observe and manipulate your application at runtime. This works […]

Memory bugs are tricky. Leaks have a clear impact on performance, and quickly become hard to spot when heap allocated objects move too much. Memory access bugs, on the other hand, make your program crash right away, if you're lucky. In less desirable cases, they may end up corrupting random objects on the heap, and […]

What is Akademy? Akademy is the yearly conference for the KDE community, which is a community devoted to creating free software for desktop and mobile. Typically, Akademy takes place in a different city each year. However, due to the pandemic, the conference was online this time around. September 4-11 marked the dates of Akademy 2020. […]

We have just released version 1.2.0 of Heaptrack, the fast heap memory profiler for C++/Linux applications. A bit of Background The Heaptrack fast heap memory profiler allows you to track all heap memory allocations at run-time. Afterwards, you can use the accompanying GUI tool to find optimization opportunities in your code by analyzing the recorded […]

We are pleased to announce a new release of our Hotspot Linux perf performance analysis GUI, Hotspot version 1.3.0! Hotspot is a replacement for perf reportthat takes a perf.data file, parses and evaluates its contents, and then displays the result in a graphical form. You can read a bit more about Hotspot here. Overview of […]

TL;DR: If you choose a default translation in your Qt application based on a locale name like this: then please change it to: Some of your users (me!) will be thankful that your application appears in the same language as the rest of their system. Background I'm a Polish guy working with computers, mostly on […]

Today's blog post is about something that should be simple and apparently it causes trouble: how to declare a qHash overload for a custom datatype. This is necessary when we want to use custom datatypes as keys in a QHash. From the documentation: A QHash's key type has additional requirements other than being an assignable […]

After four months of intensive development work, I am happy to announce that the first QStringTokenizer commits have landed in what will eventually become Qt 6.0. The docs should show up, soon. While the version in Qt will be Qt 6-only, KDAB will release this tool for Qt 5 as part of its KDToolBox productivity […]

In the last blog post we saw an essential, C++ oriented, Visual Studio Code setup. That was enough to get going right away, but we can still definitely do more and better. Here I'll show you how to get a complete setup for your qmake and CMake projects, all this while also wearing a Qt […]

My first project when I entered KDAB was the migration of a multi-million lines Motif application to Qt... feels quite scary said like that. Fortunately, migrations from any toolkit to Qt is something KDAB has been doing from the beginning, and has lots of experience with. You may be wondering what this has to do […]

Qt has a long history. The first stable version was released before the first version of C++ was standardized and long before the different C++ compiler vendors started shipping usable implementations of the C++ standard library. Because of this, Qt often followed (and still follows) some design idioms that feel unnatural to the usual C++ […]

We have released version 2.11.1 of our Qt application introspection tool GammaRay. The changes mainly focus on establishing full compatibility with Qt 5.14 as well as bugfixes and performance improvements, but there's also a few new features. Areas most affected by changes in Qt 5.14 are the inspection of Qt Quick software rendering, deployment on […]

A few weeks ago, we published an article with an overview of Visual Studio Code through the eyes of a Qt developer. In this short blog series, I will show you how to get up to speed with a Qt project using Visual Studio Code more in detail. Before digging into the Qt parts, I'd […]

Working on color imagery for QiTissue recently, I realized we were accidentally losing the alpha channel in multiple places. For efficiency reasons, we keep colors in memory using the QRgb type, and convert that to/from QString for serialization purposes via QColor as needed. Here's what I discovered about why that doesn't work, and some ways […]

Did you miss the past Qt World Summit? Were you there, but you couldn't attend that talk or two that you really wanted to see because the conference was so, so packed with awesome content? Fear no more! We are glad to announce that the talks at the past Qt World Summit 2019 in Berlin […]

Supervisory control and data acquisition (SCADA) systems have been around since the 1950's, far longer than most other types of computer applications. Their rock-solid performance has been responsible for the streamlining of any industry that needs precise and consistent controls: building automation, energy management, part machining, printing and packaging, robotic assembly, ship building, water treatment, […]

A few days ago Marc Mutz, colleague of mine at KDAB and also author in this blog, spotted this function from Qt's source code (documentation): Apart from the mistake of considering empty strings not uppercase, which can be easily fixed, the loop in the body looks innocent enough. How would we figure out if a […]

While the concept of multithreading may be straightforward, code with threads is responsible for some wicked bugs, which can be nearly impossible to reproduce or track down. This makes writing bullet-proof code using threads a tall order. Let's look a little deeper into why that is. First, you need better than average knowledge about the […]

Continuing our blog series about KDToolBox, this time we will discuss UiWatchDog, a keepalive monitor for the GUI thread. Alive? A fundamental rule when writing applications in event-driven UI frameworks such as Qt is: do not ever block the GUI thread! The GUI thread is also usually called the main thread of the application -- […]

Back in February we wrote about our work to add 'MacOs touch bar' support to Qt. Between then and now, support has been added in QtCreator: However, the changes have not been integrated upstream in Qt, which means there is still no easy way to add support to your own applications. KDAB is happy to […]