Licensing Issues

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GTK+ is released under the GNU Lesser General Public License (LGPL). To avoid any confusion or misinterpretation, I am going to quote directly from http://www.gtk.org/:

GTK+ is an Open Source Free Software GUI Toolkit, primarily developed for use with the X Window System. Everything about GTK+ from the object-oriented design to the Free Software LGPL licensing allows you to code your project with the most freedom possible. You can develop open software, free software, or even commercial non-free software without having to spend a dime for licenses or royalties. ^[1]

According to the GNU Web page on licensing, the GNU LGPL is a free software license that permits linking with non-free modules. ^[2]

^[1] Amundson, Shawn T. The Gimp Toolkit [online]. [cited Sept. 4, 2000]. Available from Internet: www.gtk.org

^[2] Free Software Foundation, Inc. GPL-Compatible, Free Software Licenses [online]. [cited Nov. 26, 2000]. Available from Internet: www.gnu.org/philosophy/license-list.html

A Note on GNOME, KDE, and MS Windows

This book is going to focus on the GTK+ widget set, but developers who will be developing only for GNOME may want to investigate the use of the GNOME libraries. These libraries are built on GTK+ and add functionality and simplicity to the GTK+ widgets. If, for example, your corporation has settled on GNOME as the standard for your Linux desktops, that library may be of use to you. This work, however, will only make use of the GTK+ widget set because of the desire to build applications that can work across both the KDE and GNOME desktops ”and, with the port of GTK+ to Microsoft Windows, even to that environment.

Regarding the port of GTK+ to Windows At the time of this writing, there is a caveat emptor warning on the GIMP for Windows Web page (http:// user .sgic.fi/~tml/gimp/win32/). Tor Lilqvist, the site author, does not feel that GIMP and GTK+ for Win32 is ready for prime time (my description), and those libraries should not be used in production systems. You will have to consider that, but you should also consider that I have been using them for nearly a year and have never had any significant problems. (And I believe it can only improve in the future.) For those reasons, I do not hesitate to use and recommend them.

A Note About Using C

A lot of VB developers feel uncomfortable using C because they think it is too complicated and doesn t allow for fast enough development time. Although that may be true about C, it is not true about the GTK+ widget set. When you use the GTK+ widgets (and the GIMP Drawing Kit and GLib, the building blocks on which GTK+ is built), the amount of C needed is rather limited. First off, GLib provides a full set of type-safe datatypes and data manipulation functions that account for shortcomings in the C language. And those functions are much simpler to use than their raw C counterparts. When you add in an Integrated Development Environment or code builder like Glade, you further reduce the amount of code you have to write from the ground up.

An in-depth review of pointers in C will help. Because many of the GTK+ constructs used later are objects referenced by pointers, knowing how C implements and uses pointers will be useful.

I am going to assume the reader has at least a passing knowledge of C; this book isn t going to present a C tutorial or review. We are going to hop right in.

only for RuBoard - do not distribute or recompile