Some time ago, I noticed that a unit test was quite slow, using 100% CPU for a number of seconds at one point in the test. I used perf and KDAB's Hotspot to record and examine where the CPU cycles were spent in that unit test, and I quickly noticed that a lot of time […]

It is our pleasure to introduce a shiny new Maps & Navigation solution for QML developers! This QML plugin is a joint effort between KDAB & General Magic to bring the excellent General Magic Maps and Navigation SDK to the QML world. What makes the General Magic QML plugin special? It's easy to use. With […]

KDSoap 2.0.0 was just released! What is KDSoap? KDSoap is a tool for creating client applications for web services, without the need for any further component such as a dedicated web server. This tool makes it possible to interact with applications which have APIs that can be exported as SOAP objects. The web service then […]

(Apologies for the clickbait in the post title! But I'd really like people who are searching for solutions to read this.) Between Qt 5.14 and Qt 5.15, my colleague, Marc Mutz, and I submitted a series of patches to Qt that added "range constructors" to the Qt containers. This brought Qt containers one step closer […]

After many struggles with using git LFS on repositories that need to store big files, I decided to spend some time on checking the status of the built-in partial clone functionality that could possibly let you achieve the same (as of git 2.30). TL;DR: The building blocks are there, but server-side support is spotty and […]

In the previous blog post of this series, we discussed KDToolBox::QtHasher, a helper class that allows us to use unordered associative containers datatypes which have a qHash() overload but not a std::hash specialization. The majority of Qt value classes indeed are lacking such a specialization, even if they do provide a qHash() overload. For our […]

Note: This is the English translation of the article first published in German Intro The ESE Congress is one of the lead events for Embedded Software Engineering in Germany. This year it was held digitally for the first time, so that participation was also possible via video. Over five days, there were 3 keynotes and […]

For many developers, QNX is the operating system of choice, when it comes to developing on embedded systems. However, the performance limits are exceeded quickly, especially if you're working on low-end hardware. As a result, you'll likely need to perform an investigation to find the bottlenecks that contribute to reaching these limits, in order to […]

Sometimes it's useful to establish a connection between a signal and a slot that should be activated only once. This is not how signal/slot connections normally behave. Remember that, when a connection is established, it will stay active until: the connection is explicitly disconnected; or the sender object is destroyed; or the receiver object is […]

Another day, another blog post about KDToolBox, KDAB's collection of miscellaneous useful C++ classes and stuff. Today, we'll talk about ways to throttle your signal/slots connections -- in other words, how to activate a slot less often than the emission rate of the signal it's connected to. The usual reason why you may want something […]

In the previous blog post about qHash, we explained: how to declare an overload of qHash for your own datatypes, how to hash Qt datatypes for which Qt does not provide a qHash overload, and why you can't use a type from the Standard Library (or just another library) as a key in QHash (newsflash: […]

A long time ago, I wrote a post about creating custom shapes in Qt Quick, via the scene-graph APIs. That post covered defining suitable geometry to draw a part of a circle, known also as a 'sector', efficiently, since such sectors occur commonly in instrument and vehicle interfaces. I started writing the second part, about […]

Einleitung Der ESE Kongress ist die Leitveranstaltung für Embedded Software Engineering in Deutschland. In diesem Jahr fand er erstmals digital statt, so dass die Teilnahme auch per Video möglich war. An fünf Tagen gab es 3 Keynotes und 96 Fachvorträge aus allen Bereichen der Embedded Softwareentwicklung. Anton Kreuzkamp von KDAB sprach über maßgeschneidertes Code-Refactoring mit […]

Here, at KDAB, we get to spend 10% of our time on learning what we don't know or practicing and improving what we already know. Recently, I decided to use that time to learn more about the Qt Quick Rendering Engine. The best way to do so, I found, is to use it in a […]

We've released KDDockWidgets 1.3.0! KDDockWidgets is a framework for custom-tailored docking systems in Qt. The main highlights for this release are PySide6 and experimental QtQuick support. The QtQuick backend isn't production ready, but you can already build with -DKDDockWidgets_QTQUICK=ON, run the examples under examples/qtquick/dockwidgets/ and start reporting issues. Here's the full list of changes: Experimental […]

Another day, another blog about some of KDAB's utility classes. Now it's the turn of KDSingleApplication, a class that helps implement applications that follow the single-instance policy. What is a single-instance policy? Single-instance policy refers to those applications that want to spawn a unique instance for a given user session. Even when launched multiple times, […]

CMake 3.19 was officially released a couple of months ago, and one of the biggest – and most exciting – new features is the addition of presets. What are presets, you might ask, and why should we be excited about them? Presets are a bunch of pre-set CMake options that enable developers to ensure that […]

As was previously discussed, since the 6.0.0 release of Qt, Qt 3D no longer ships as a pre-compiled module. If you need to use it on your projects, try out the new features, or just see your existing application is ready for the next chapter of Qt's life, you need to compile Qt 3D from […]

You know the drill: in C++ you need to #include header files that declare the types and functions from the libraries that you use. Qt is no exception in this regard. Qt follows a very nice convention for its own datatypes: if you need to use a type called QType, then use #include <QType>. This […]

This is the third and last installment of our series about full stack tracing. If you haven’t read them yet, you’ll probably want to check out the introduction and tool setup portions first. In this blog, we’re going to focus on visualizing and interpreting full stack traces. At this point, we’re going to assume that […]