Function lua_getmetatable

3rd/lua-5.4.3/src/lapi.c:769–793

LUA_API int lua_getmetatable (lua_State *L, int objindex) {
  const TValue *obj;
  Table *mt;
  int res = 0;
  lua_lock(L);
  obj = index2value(L, objindex);
  switch (ttype(obj)) {
    case LUA_TTABLE:
      mt = hvalue(obj)->metatable;
      break;
    case LUA_TUSERDATA:
      mt = uvalue(obj)->metatable;
      break;
    default:
      mt = G(L)->mt[ttype(obj)];
      break;
  }
  if (mt != NULL) {
    sethvalue2s(L, L->top, mt);
    api_incr_top(L);
    res = 1;
  }
  lua_unlock(L);
  return res;
}


LUA_API int lua_getiuservalue (lua_State *L, int idx, int n) {