CSteamworks is a C ABI Wrapper for Valve's C++ Steamworks API.
The primary use case for CSteamworks is to act as a buffer between a scripting language and the Steamworks C++ Interfaces.
CSteamworks is the backbone behind a number of third party implementations of the Steamworks API for various scripting languages.
One such project that relys on the stable ABI exposed via CSteamworks is Steamworks.NET.
CSteamworks is released under the MIT license.