Library
This is an example of a library. You may see a list of other libraries used on Rosetta Code at Category:Solutions by Library.

The OpenGL User Toolkit, or GLUT, is a toolkit for abstracting operating-system-specific details from programmers writing OpenGL applications. The original is available, but no longer maintained. There are [multiple implementations of GLUT's API available http://www.opengl.org/resources/libraries/windowtoolkits/].