WxWindows is a set of libraries that allows C++ applications to compile and run on several different types of computer, with minimal source code changes. There is one library per supported GUI (such as Windows, GTK+, Motif, and Mac). As well as providing a common API (Application Programming Interface) for GUI functionality, it provides functionality for accessing some commonly-used operating system facilities, from copying and deleting files to socket and thread support. wxWindows is a 'framework' in the sense that it provides a lot of built-in functionality, which the application can use or replace as required, thus saving a great deal of coding effort. Basic data structures such as strings, arrays, linked lists and hash tables are also supported.