Qt is a C++ application framework from Trolltech that lets you write native applications that can be compiled cross-platform. This means that the source code only needs to be written once, yet support Linux, Windows CE/98/XP/Vista, Mac OS X, UNIX, and Embedded Linux. To deploy, you simply compile it for your target platform. One well-known application taking advantage of this kind of capability is Google Earth, which is available for Linux, Windows, and Mac OS X. Qt makes it easy for Google to maintain its code base and simultaneously support several platforms.
When it comes to embedded operating systems, Qt is supported by embedded Linux and, with the beta release of Qt 4.4, it supports Windows CE 5.0/6.0, and Windows Mobile 5.0/6.0. In this article, I create native applications for Windows CE using Qt.
Windows CE targets different segments of the embedded marketplace. Windows Mobile, for instance, targets Smartphones and Pocket PCs. Windows Mobile has a specialized UI, and provides lightweight office and communication applications. Nevertheless, it's still Windows CE. Generally speaking, when I refer to Windows CE, I include Windows Mobile and any other Windows CE flavor that supports the Windows CE Standard SDK 5.0 (or later).