This driver was designed for the GTK+ version 2. It can be compiled in Windows or UNIX.
Although GTK has layout elements they are not used. IUP fill, vbox, hbox and zbox containers are implemented independent from the native system.
The oldest GTK version that can be used is 2.4, oldest versions will not compile. But using versions older than 2.12 several features will not work. Critical features need at least version 2.8.
Currently it is not available for IRIX, AIX and SunOS. But is it available for SunOS10 and it is not available for Linux24.
The GTK driver can be compiled and used in Windows, but it is not recomended since it is slower and much more memory consuming than the IUP native Windows driver.
GTK uses UTF-8 as its charset for all displayed text, so IUP will automatically convert all strings to (SetAttribute) and from (GetAttribute) UTF-8. To use UTF-8 strings set the global attribute UTF8AUTOCONVERT to NO.
When using DLLs in Windows, the "iup.dll" uses the Win32 driver. So applications that dynamically load IUP will always use the "iup.dll", for example Lua using require. To use the IUP GTK dll in Windows you must rename the "iupgtk.dll" to "iup.dll", so the GTK driver will be loaded instead of the Win32 driver.
GTK is in fact composed of several libraries. The GTK package contains the GDK library and depends on the ATK, Cairo, Glib and Pango libraries.