how to transfer Lua Function and function params between different Lua state?

[chuang <lichuang1982@...>]

I want to write a C module,when Lua call this module's spawn function,it create a new Lua state,and the new Lua state can call its Lua function,like this:

require("qnode")

function test(a)

  print("in test")

  print(a)

end

qnode.spawn(test, 100)

but,when i review the Lua C API,seems there is no function to get the Lua function from the Lua stack.

So,how can I achieve this  purpose?