It is now possible to try the program on your own machine. First, you will need to install Qt 4.1.1 (or a later Qt 4 release), a process that is explained in Appendix A. From now on, we will assume that you have a correctly installed copy of Qt 4 and that Qt's bin directory is in your PATH environment variable. (On Windows, this is done automatically by the Qt installation program.) You will also need the program's source code in a file called hello.cpp in a directory called hello. You can type in hello.cpp yourself, or copy it from the CD provided with this book, where it is available as /examples/chap01/hello/hello.cpp.

From a command prompt, change the directory to hello, then type

qmake -project



to create a platform-independent project file (hello.pro), then type

qmake hello.pro



to create a platform-specific makefile from the project file.

Type make to build the program.[*] Run it by typing hello on Windows, ./hello on Unix, and open hello.app on Mac OS X. To terminate the program, click the close button in the window's title bar.

[*] If you get a compiler error on the <QApplication> include, it probably means that you are using an older version of Qt. Make sure that you are using Qt 4.1.1 or a later Qt 4 release.

If you are using Windows and have installed the Qt Open Source Edition and the MinGW compiler, you will have a shortcut to a DOS Prompt window that has all the environment variables correctly set up for Qt. If you start this window, you can compile Qt applications within it using qmake and make as described above. The executables produced are put in the application's debug or release folder, for example, C:\qt-book\hello\release\hello.exe.

If you are using Microsoft Visual C++, you will need to run nmake instead of make. Alternatively, you can create a Visual Studio project file from hello.pro by typing

qmake -tp vc hello.pro



and then build the program in Visual Studio. If you are using Xcode on Mac OS X, you can generate an Xcode project using the command

qmake -spec macx-xcode