ClassicAPI

ClassicAPI is a DLL for World of Warcraft 1.12.1 (Vanilla / Turtle WoW). It backports a large part of the modern WoW API — 550+ functions and 50+ events, plus much of Lua 5.1 — into the 1.12 client, so addons written for later versions (3.3.5+ or Classic Era) run with little or no change.

It hooks the engine after WoW boots and registers everything the same way WoW registers its own Lua functions. Nothing else to install — the DLL is self-contained.

The headline features. Each one takes effect as soon as the DLL loads, so your existing addons benefit without any code changes. The complete per-function reference is in docs/API.md.

The flagship feature: run modern Lua 5.1 addon code on 1.12's Lua 5.0 VM.

Everything ClassicAPI adds, in full. Each section is collapsed — click a heading to expand it. For signatures and return values, see the per-function reference in docs/API.md.

Download the prebuilt ClassicAPI.dll from the latest release (or build it yourself). It's loaded with VanillaFixes:

1. Install VanillaFixes if it isn't already.
2. Copy ClassicAPI.dll into your game directory.
3. Add ClassicAPI.dll to dlls.txt.
4. Launch the game with VanillaFixes.exe.

The bundled !!!ClassicAPI addon ships inside the DLL — no separate addon download or install step needed.

The Lua-side companion library lives in AddOns/!!!ClassicAPI/. It's a 1.12.1 / Lua 5.0 backport of the modern Blizzard helpers that aren't engine functions but that consumer code still expects to find as globals — CallbackRegistryMixin, EventRegistry, ColorMixin + CreateColor, Item / ItemLocation, MathUtil(Lerp / Clamp / CreateCounter), TableUtil (tCompare, MergeTable, SafePack, etc.), and EventUtil (ContinueOnAddOnLoaded etc.).

You don't have to install the addon manually — the DLL embeds the contents of AddOns/!!!ClassicAPI/ and registers them with the engine as a synthetic addon on startup, so the library is always available when the DLL is loaded. It fires ADDON_LOADED, supports SavedVariables, and is resolvable by name — IsAddOnLoaded("!!!ClassicAPI"), GetAddOnInfo("!!!ClassicAPI"), and ## Dependencies: !!!ClassicAPI all work as usual.

It is intentionally always-on and cannot be disabled. The library provides FrameXML-compat fixes that other addons and the DLL's own features rely on, so leaving it toggleable would let a user (or a one-off character-select uncheck) silently break them. The DLL therefore hides it from the character-select AddOns list and force-enables it every login — so it never appears as a checkbox and can't be switched off. Being hidden means it's omitted from the index-based GetNumAddOns() / GetAddOnInfo(i) enumeration, but every by-name lookup and dependency reference still resolves normally.

If you drop the folder into your Interface/AddOns/ directory, that copy's files win — the DLL's embedded version only serves files when the engine's normal scan doesn't already have a newer entry under that name. Useful for editing the Lua locally without rebuilding the DLL. The hidden + force-enabled treatment applies either way (it's keyed to the addon name, not to which copy serves the files), so the local copy is also absent from the AddOns list. The dispatch is transparent: addons consuming Mixin, ColorMixin, TableUtil, etc. behave identically in both cases.

A 1.12.1 / Lua 5.0 backport of Blizzard's Blizzard_DebugTools addon (originally shipped with the 3.0 client) lives in AddOns/DebugTools/. It's an independent addon — it doesn't use anything ClassicAPI adds, and ClassicAPI works fine without it. It's bundled here because it's the natural companion for testing and debugging anything written against the 1.12 Lua surface (with or without the ClassicAPI extensions).

Slash commands provided:

Lua globals provided (backports of 3.3.5 helpers that don't exist in 1.12):

To install: copy AddOns/DebugTools/ into your Interface/AddOns/ directory like any other addon.

Requires CMake (3.10+) and an MSVC toolchain that can target 32-bit Windows. WoW.exe is x86, so the DLL must be built as Win32; an x64 build will not load.

git submodule update --init --recursive   # fetches MinHook, picojson, tinycbor
cmake -B build -A Win32
cmake --build build --config Release

The output is build/Release/ClassicAPI.dll.

To stamp a version into CLASSIC_API_VERSION, pass -DCLASSICAPI_TAG=vX.Y.Z at configure time; the value exposed to Lua will be X*10000 + Y*100 + Z.

GPL v3 or later. See the headers in src/ for the full notice.