So far, we are still trapped with our applications on Windows. It's time to test whether our code can be built on other platforms. In this chapter, the code involved with only desktop operating systems, while we'll get a chance to build applications for mobile platforms later in this book. In terms of other desktop operating systems, there are plenty of them, and most of them are Unix-like. Qt officially supports Linux and Mac OS X, along with Windows. Hence, users of other systems, such as FreeBSD, may need to compile Qt from scratch or get prebuilt packages from their own communities. In this book, the Linux distribution Fedora 20 is used as a demonstration to introduce platform crossing. Please bear in mind that there are lots of desktop environments and theming tools on Linux, so don't be surprised if the user interface differs. Well, since you're curious, let me tell you that the desktop environment is KDE 4 with QtCurve, unifying GTK+ / Qt 4 / Qt 5 in...