SteamAppsLocation

A Windows x86 command-line tool that locates an installed Steam game by AppId. Originally part of MetaHookSv.

Usage

SteamAppsLocation.exe 70

On success, stdout contains exactly one UTF-8 absolute install path followed by a newline. Diagnostics, including Steam SDK messages, go to stderr. Failure leaves stdout empty. The AppId must be a nonzero decimal integer in the uint32 range.

The program sets SteamAppId and SteamGameId in its own process before initializing Steam; callers do not need to create steam_appid.txt.

Lookup order

1. Read HKCU\Software\Valve\Steam\SteamPath and attempt the original ActiveProcess\SteamClientDll registry repair if its canonical path differs from <SteamPath>\steamclient.dll. Failure to read, resolve or repair this value does not stop the lookup. The repair writes the expected canonical DLL path to the existing registry value; it does not require administrator access.
2. Dynamically load the bundled steam_api.dll from the executable directory and query SteamApps for the requested game's install directory. Steam API access generally requires a running Steam client and an eligible account/AppId.
3. If the DLL, exports, initialization, interface or query are unavailable, or the returned directory does not exist, scan Steam library manifests. Check Steam's primary library first, then the additional libraries in steamapps/libraryfolders.vdf. Read each appmanifest_<appid>.acf and use its installdir under steamapps/common, returning only an existing directory.

Manifest lookup works without a running Steam client or steam_api.dll, provided SteamPath and the installed game's manifest are available. Missing or malformed library configuration still permits checking the primary library. Missing, unreadable or malformed manifests are skipped. This fallback is ported from the MetaHook installer MainViewModel.GetGameInstallPath implementation.

Exit codes

Code	Meaning
0	An existing install directory was found through either lookup method.
1	Missing, extra or invalid AppId argument.
4	SteamPath could not be read.
5	ActiveProcess SteamClientDll could not be read.
6	SteamClientDll registry repair failed.
7	SteamApps interface, install-directory query or returned directory was unavailable.
8	Steam API DLL/export/initialization was unavailable, or an unexpected error occurred.
9	The expected steamclient.dll path could not be resolved.
10	The active SteamClientDll path could not be resolved or compared.

After both lookup methods fail, the first failing stage determines the exit code. A successful lookup returns 0 even when an earlier registry or API stage failed.

Build and test

Requirements: Windows, Visual Studio 2022 with the C++ desktop workload and Windows SDK, and CMake 3.21 or newer. The x86 Steam SDK headers, import library and runtime are provided by the SteamSDK submodule at thirdparty/SteamSDK; no MetaHook checkout is required.

Clone with submodules:

git clone --recurse-submodules https://github.com/MetaHookSv/SteamAppsLocation.git
cd SteamAppsLocation

For an existing checkout, initialize or update the SDK before building:

git submodule update --init --recursive

scripts\build-SteamAppsLocation-x86-Release.bat
scripts\build-SteamAppsLocation-x86-Debug.bat

These scripts configure, build, run CTest, and install to install\x86\<Configuration>. The install directory contains only the EXE, PDB and Steam API DLL; the README, license and SDK notice stay in the repository. The build uses the static MSVC runtime.

Equivalent commands for Release:

cmake -G "Visual Studio 17 2022" -A Win32 -S . -B build/x86/Release -DCMAKE_INSTALL_PREFIX=install/x86/Release
cmake --build build/x86/Release --config Release --parallel
ctest --test-dir build/x86/Release -C Release --output-on-failure
cmake --install build/x86/Release --config Release

Tests use temporary libraries, simulated SDK DLLs and isolated temporary registry keys. They do not modify the real Steam registry keys or require Steam to run. The copied import library is retained with the SDK but the executable does not link it, allowing manifest fallback when the DLL is absent.

Builds and releases

GitHub Actions builds and tests x86 Release for main pushes and pull requests. Tags matching v* create a release. Both workflows package the installed files as SteamAppsLocation-windows-x86.7z and verify the archive with 7z t.

License

Tool code is distributed under the original MIT license. Valve's SDK files retain their original copyright notices; see STEAM-SDK-NOTICE.md.