Jules' Utility Class Extensions (documentation)

 JUCE (Jules' Utility Class Extensions) is an all-encompassing C++ framework for
 developing cross-platform software.
 .
 It contains pretty much everything you're likely to need to create most
 applications, and is particularly well-suited for building highly-customised
 GUIs, and for handling graphics and sound.
 .
 This package contains html documentation for the JUCE API.