fluffos/docs/index.mdx

---
title: FluffOS
slug: /
---

# FluffOS

FluffOS is a high-performance game engine (an LPMUD driver), commonly used for building MUDs — see
[LPMud](https://en.wikipedia.org/wiki/LPMud). Started as a collection of patches to the last release
of MudOS, FluffOS has gone through major rewrites and bugfixes to support new features while
maintaining backward compatibility with existing mudlibs.

The codebase has three parts:

- **LPC interpreter** — parses and executes LPC programs.
- **Network server** — manages client connections and exposes them to LPC. Supports TELNET, TLS and WebSocket.
- **Glue interface**
  - **Efuns** — built-in C/C++ functions callable from LPC programs.
  - **Applies** — callback functions the driver invokes on LPC objects for game events.

:::tip[Current release]
The current release is branch `master` — CMake build system, supported on Ubuntu, macOS,
Windows (MSYS2/MinGW64), and WebAssembly.
See [all releases on GitHub](https://github.com/fluffos/fluffos/releases).
:::

## Explore the documentation

<div className="row">
  <div className="col col--4 margin-bottom--lg">
    <div className="card" style={{height: '100%'}}>
      <div className="card__header"><h3>🚀 Getting Started</h3></div>
      <div className="card__body">
        Build the driver from source on Linux, macOS, Windows — or for the browser with WebAssembly.
      </div>
      <div className="card__footer">
        <a className="button button--secondary button--block" href="/build">Build Guide</a>
      </div>
    </div>
  </div>
  <div className="col col--4 margin-bottom--lg">
    <div className="card" style={{height: '100%'}}>
      <div className="card__header"><h3>📖 LPC Language</h3></div>
      <div className="card__body">
        The LPC language as implemented by FluffOS: types, constructs, the preprocessor, and compiler diagnostics.
      </div>
      <div className="card__footer">
        <a className="button button--secondary button--block" href="/lpc/">Language Reference</a>
      </div>
    </div>
  </div>
  <div className="col col--4 margin-bottom--lg">
    <div className="card" style={{height: '100%'}}>
      <div className="card__header"><h3>⚙️ Efuns</h3></div>
      <div className="card__body">
        The complete reference of built-in functions the driver exposes to LPC code, grouped by topic.
      </div>
      <div className="card__footer">
        <a className="button button--secondary button--block" href="/efun/">Efun Reference</a>
      </div>
    </div>
  </div>
  <div className="col col--4 margin-bottom--lg">
    <div className="card" style={{height: '100%'}}>
      <div className="card__header"><h3>🔔 Applies</h3></div>
      <div className="card__body">
        Callbacks the driver invokes on your objects: master security hooks, object lifecycle, and player connections.
      </div>
      <div className="card__footer">
        <a className="button button--secondary button--block" href="/apply/">Apply Reference</a>
      </div>
    </div>
  </div>
  <div className="col col--4 margin-bottom--lg">
    <div className="card" style={{height: '100%'}}>
      <div className="card__header"><h3>💡 Concepts</h3></div>
      <div className="card__body">
        How LPC, objects, and the driver fit together — simul_efuns, hot reload, networking, and more.
      </div>
      <div className="card__footer">
        <a className="button button--secondary button--block" href="/concepts/">Concept Guides</a>
      </div>
    </div>
  </div>
  <div className="col col--4 margin-bottom--lg">
    <div className="card" style={{height: '100%'}}>
      <div className="card__header"><h3>🔧 Driver Internals</h3></div>
      <div className="card__body">
        Runtime configuration, the VM stack machine, memory allocation, and how to add your own efuns.
      </div>
      <div className="card__footer">
        <a className="button button--secondary button--block" href="/driver/">Driver Docs</a>
      </div>
    </div>
  </div>
</div>

## Features

- Builds on Ubuntu, macOS, and Windows natively with CMake — plus a WebAssembly target that runs a full mudlib in the browser.
- UTF-8 native, with transparent input/output encoding support. (Emojis!)
- WebSocket support!
- TLS support!
- SHA512 crypt by default.

### Features previously released

- Mostly backward-compatible with MudOS. (Upgrading should be easy!)
- Lots of bug fixes, including a full CHECK_MEMORY-enabled testsuite pass.
- Compiles on modern Linux distros, 32-bit & 64-bit, CYGWIN support.
- 64-bit LPC runtime: LPC `int` is always a 64-bit int, LPC `float` is a C double.
- MXP, GMCP, ZLIB.
- IPv6 support (optional).
- ICONV support: code in UTF-8, dynamic translation on output (optional).
- POSIX timer for better time precision (optional).
- Stricter type checking (optional).
- libevent integration, epoll backend.

## License & Copyright

> Copyright 2019-2023 Yucong Sun

> Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated
> documentation files (the "Software"), to deal in the Software without restriction, including without limitation the
> rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit
> persons to whom the Software is furnished to do so, subject to the following conditions:
> The above copyright notice and this permission notice shall be included in all copies or substantial portions of the
> Software.
> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
> WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
> COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
> OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

### Historical

For the pre-2019 license and copyright, see
[Copyright](https://github.com/fluffos/fluffos/blob/master/Copyright); for older release notes, see
[ChangeLog.fluffos-3.x](https://github.com/fluffos/fluffos/blob/next-3.0/ChangeLog.fluffos-3.x).