Function lua_callk

third-party/lua-5.5.0/src/lapi.c:1037–1056

LUA_API void lua_callk (lua_State *L, int nargs, int nresults,
                        lua_KContext ctx, lua_KFunction k) {
  StkId func;
  lua_lock(L);
  api_check(L, k == NULL || !isLua(L->ci),
    "cannot use continuations inside hooks");
  api_checkpop(L, nargs + 1);
  api_check(L, L->status == LUA_OK, "cannot do calls on non-normal thread");
  checkresults(L, nargs, nresults);
  func = L->top.p - (nargs+1);
  if (k != NULL && yieldable(L)) {  /* need to prepare continuation? */
    L->ci->u.c.k = k;  /* save continuation */
    L->ci->u.c.ctx = ctx;  /* save context */
    luaD_call(L, func, nresults);  /* do the call */
  }
  else  /* no continuation or no yieldable */
    luaD_callnoyield(L, func, nresults);  /* just do the call */
  adjustresults(L, nresults);
  lua_unlock(L);
}