C++ Get lua table in C++ luascriptinterface

[Itutorial]

I need to create a c++ table using a table created and called from lua.

What im sending in lua

local playerList = {target:getId()}
local creature = Game.createUniqueNpc(name, pPos, playerList, 0, 1)

c++

int LuaScriptInterface::luaGameCreateUniqueNpc(lua_State* L)
{
    // Game.createUniqueNpc(npcName, position, playerIdList [, extended = false[, force = false]])
    Npc* npc = Npc::createNpc(getString(L, 1));
    if (!npc) {
        lua_pushnil(L);
        return 1;
    }

    const Position& position = getPosition(L, 2);
    std::list<uint32_t> list;

    lua_gettable(L, 3); // Doesn't seem to work tried a lot of different things instead of this
    while (lua_next(L, -1) != 0) { // Error here
        std::cout << "Attempting to call values from table" << std::endl;
        uint32_t tmpID = getNumber<uint32_t>(L, -1);
        std::cout << "Called number value from table" << std::endl;
        if (tmpID) {
            list.push_back(tmpID);
            std::cout << "Pushed number to list." << std::endl;
            lua_pop(L, 3);
        }
    }

    bool extended = getBoolean(L, 4, false);
    bool force = getBoolean(L, 5, false);