SteamForwarder Save

steam_api.dll implementation for wine. Your windows games now can interact with your linux steam! (This repo mirrors

Project README

SteamForwarder status

steam_api.dll implementation for WINE. Your windows games now can interact with your linux steam! What does it mean? It means this tool provides a component for WINE named steam_api.dll. It works like for example opengl32.dll provided by WINE which allows windows programms to access OpenGL API under linux. If opengl32.dll supplies interface to, the steam_api.dll does the same thing but for (which is provided by Valve for linux steam games).

! Attention !

Recently Valve has introduced new version of SteamPlay that includes a core feature of the SteamForwarder project - to connect Windows games with Linux Steam. So since this moment SteamForwarder can be considered as deprecated and the project won't be in the active developement any more. Nevertheless I will continue trying to fix any bugs reported if any.


The author is not liable for any damage resulting from the use of this software. User might break his games, steam, OS or even computer. User account might to be banned by Valve. The legal status of the tool is uncertain and nobody have been banned so far but EVERYTHING THAT YOU'RE DOING, YOU'RE DOING ON YOUR OWN RISK!


There are a few known problems with this tool. Some of them will be solved in future, others are not solvable.

SteamForwarder is NOT able to run by design:

  • Games what trying to detect steam process bypassing steam_api.dll
  • Games with statically linked steam_api.dll

SteamForwarder is NOT able to download:

  • Everything that steamcmd or steam are not able to download

For pre-2014 steam api it might be worthy to use SteamBrige.

Usage dependencies

  • steamcmd (not required with experimental flag --steamnative)
  • python3 (for installer script)
  • wine-devel (including winedump, winegcc and headers)
  • make

Note that you may need to build if the sf_install script won't be able to find matching precompiled library. The installation script will try to setup mostly matching library from existent ones though. If you want to force the library building you can use the --strict command line option but it needs the build dependencies installed in your system to succeed.

Build dependences

All usage dependencies plus

  • nim compiler of version 0.18.0 or higher
  • binutils ( and in particular)
  • binutils-devel (including bfd.h and dis-asm.h)


This is a common usage scenario of SteamForwarder for users. Some hints for experts can be found in the section below.

  • Download redist.tar.bz2 from latest release of SteamForwarder at the releases page.
  • Unpack it to the folder you want.
  • Open a terminal in the folder the sf_install script was unpacked (share/SteamForwarder or bin).
  • Type python3 sf_install --help to learn command line options of installer tool.
  • Launch your linux steam client if you decided to use --steamnative option, otherwise close the steam client if it is running (it may conflict with the steamcmd).
  • Use sf_install to install your windows game. E.g. for Paladins it command might look like python3 sf_install 444090. The steam AppId of the game can be found in the url of the game page on the steam store site. It might be necessary to play around the commandline options to install the game (see tips below)
  • For already installed games it is possible to use --no-download option to trigger generation without actual game instalation.
  • Launch your linux steam (don't allow it to update your windows games, in some cases the linux steam just erases the game and says that it is updated. Use sf_install to update windows games.)
  • Run installed game via runscript generated. (Its location will be printed after sf_install will install the game.)

There is a little video example that shows typical use case.

Some important tips:

  1. If you dont want to install steamcmd, it is possible to avoid it by using --steamnative flag in sf_install
  2. If the game does not installing with standart method try to use --depot option
  3. There is install target for make, so you can build a package or install SteamForwarder to your system. Don't forget about PREFIX and DESTDIR variables.
  4. If sf_install can not write the run script or can not find steam_api.dll check the game installation, it may be not even installed (see 2). In other case, it might be incompatible with SteamForwarder.
  5. There is no universal way to install any game. Keep trying other options and other aproaches.
  6. Save frequently used parameters by passing the --store commandline option to the sf_install script or/and edit them at $HOME/.config/SteamForwarder/config.json.

Found a bug?

Feel free to post the issue. Don't forget to attach the wine log with WINEDEBUG=trace+steam_api environment variable set and log from sf_install and the steam client (CONSOLE tab) if available. If you're starting the game from the runscript generated by the sf_install the required log can be found in the runscript folder (it's named lastrun.log). The script itself also can be a key to a problem. If you know how to improve SteamForwarder or even already improved it in your fork, your Pull Request will be appreciated! Any poor-languachisms, mistakes and other text-related issues found in the documentation also can be considered as bugs and can be reported or fixed by PR.

Want to contribute?

I assume that there are not so much people is familiar with the Nim language, so the good starting point would be the python side of the project. It includes the sf_install script and its dependencies at the installer/ folder. I'm mostly focused on the Nim side, so the installer script has many things to improve. But the python scripts improvements are not only accepted contributions. There is no particular codestyle or specific rules and every request will be reviewed in the individual order. The only rule is: "Do not break things!".

Implementation details

The SteamForwarder may be represented as two almost independent parts: and service tools. Service tools may also be devided to user tools and developer tools.

For a moment there is only one user tool - sf_install. This script tells steam or steamcmd to download the game and prepares SteamForwarder to work with this game, including the run scripts creation and building. It has arbitary user-friendly interface with many settings managed by command line switches.

Another pair of tools can be related to developers tools. Their work invisible for ordinal user. But before describing them, it is necessary to describe the build process. So the target of whole build process is a library which implements everything implemented in steam_api.dll file from the game installed. The target library should forward every call to the library on linux side. The building of starts from gathering information about original steam_api.dll. There are two kinds of information: version dependent and version independent.

The version dependent information is represented by the library's exported symbols and can be obtained via winedump tool from wine-devel. As the result, there is steam_api.spec file will be created. But the information from this file is not enough to build the library: there aren't any information about the symbols arguments. In previous versions of the SteamForwarder this problem was solved by parsing header files which Valve supplies to game developer. But headers are only available for latest steam API version and their usage for old steam games causes problems. The solution of such a situation was found in parsing various versions of and search for mostly compatible with original steam_api.dll, then extract the information about amount of symbol arguments via the dllparser tool.

Another part of information - version independent. This one should be extracted from and does not dependent from steam_api.dll. The extraction is being performed by the sigsearch tool. The tool provides information about steam API classes and their methods. As soon as this information does not depend on game, it was included to this repository at file signatures.txt.

When both of information kinds is collected, the build stage begins. Main job which is being done by is ABI conversion from MSVC calling conventions to GCC ones and vise versa. It means that a little chunk of the wrapping code should be added to each steam API function or method. The wrapping code in almost all cases is very similiar. Implementing it by hands could make me crazy. Thats why is implemented in the Nim programming language. Nim has wonderful metaprogramming abilities and compiles directly to C, so I can rely on a few macros to generate the whole steam API.

Open Source Agenda is not affiliated with "SteamForwarder" Project. README Source: xomachine/SteamForwarder
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