Wikipedia
JUCE
JUCE is an open-source cross-platform C++ application framework, used for the development of desktop and mobile applications. JUCE is used in particular for its GUI and plug-ins libraries.
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, Visual Studio and Code::Blocks.