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MonoLuaCallback

In ZLua docs, the [LuaCallback] concept is implemented as MonoLuaCallbackAttribute (analogous to Unity's MonoPInvokeCallback): marks a C# function pointer callable directly from native / Lua.

using ZLua;

[MonoLuaCallback(typeof(LuaCSFunction))]
private static int MyNativeEntry(IntPtr L)
{
    // Only int (IntPtr L) signature is allowed
    return 0;
}

:::info Usually not needed manually When Lua calls C# members, bridge functions are registered automatically on first call. You do not need [MonoLuaCallback] on every C# method. Use it only when handing a C# function pointer to the Lua C API (e.g. lua_pushcfunction). :::

Attribute Definition​

[AttributeUsage(AttributeTargets.Method)]
public sealed class MonoLuaCallbackAttribute : Attribute
{
    public Type DelegateType { get; }
    public MonoLuaCallbackAttribute(Type delegateType);
}
ParameterDescription
delegateTypeUsually typeof(LuaCSFunction), i.e. int (IntPtr L)

Signature Limits​

Lua C API callbacks only support:

delegate int LuaCSFunction(IntPtr L);

Therefore MonoLuaCallback cannot be used for:

  • Exposing arbitrary C# method signatures directly to Lua (use MethodBridge)
  • Business APIs with ref/out or multiple parameters

Use Cases​

ScenarioNeeded?
obj:Method() / Type.Static()❌ Auto-bridged
Lua function → C# delegate parameter❌ Implicit marshal; see callback guide
ZLua internal __zlua_* native callback registration✅ Framework-internal
Extending native modules, custom lua_pushcfunction✅ Advanced

Relation to Auto-Registration for Lua → C#​

Auto-registered bridges may themselves carry [MonoLuaCallback]; transparent to game code.

Il2Cpp Notes​

On Player, native bridges are C++-generated; game C# rarely needs MonoLuaCallback. When extending Il2Cpp plugins, follow the same int (lua_State* L) constraint as Mono.