TnFOX

The TnFOX portability toolkit is a fork of the FOX GUI toolkit with most of the added code implementing orthogonal features (i.e. not substantially changing the FOX API) such that applications developed for FOX can be easily recompiled for TnFOX. Unusually, TnFOX also contains API emulations of some Qt library classes - according to the author, this was done to port a substantial project from Qt to FOX. Most of the added features implement a full "portability toolkit" library such that one can write one program to run anywhere - this differs from FOX which mostly just provides the GUI portability alone. TnFOX is therefore an example of an operating system abstraction layer.

Unlike FOX, TnFOX supports only a restricted set of C++ compilers and operating systems. It only supports Microsoft's C++ compiler v7.1 and later, GCC v3.2 and later and Intel C++ compiler v8 or later. It also only runs on Windows 2000 or later, Linux 2.6 kernels or later, FreeBSD and Mac OS X 10.4 or later, though on any processor or architecture.