JUCE is a C++ toolkit for building cross-platform applications on PC/Mac/Linux. Particularly good for complex, customised GUIs and audio/midi processing, it also includes a vast range of classes to help with all your day-to-day programming tasks.

The aim of Juce is to allow software to be written such that the same source code will compile and run identically on Windows, Mac OS X and Linux platforms. It supports various development environments and compilers, such as GCC, Xcode and Visual Studio.