problem lua_yield and lua_resume

["mos" <mmosquito@...>]

Hi!
	I am very sorry to paste the full code -- or I can not explain the
whole thing clearly
	the code will use lua5.1 luabind0.7 , if you do not use luabind0.7 ,
it doesn't matter, you may help me also

	the source code of c++

extern "C" {
	#include "lua.h"
	#include "lualib.h"
	#include "lauxlib.h"
}

#include <luabind/luabind.hpp>
#include <luabind/error.hpp>
#include <string>
#include <stdio.h>
#include <iostream>
#include <sstream>

using namespace luabind;
using namespace std;

lua_State *L2;
string swait;
void MyYield(const char*szWait)
{
	cout << "thread is waiting for " << szWait << endl;
	swait = szWait;
	lua_yield(L2,0);
}

int luaMyYield(lua_State* LL)
{
	MyYield(lua_tostring(LL,1));
	return 0;
}

void RegisterLua()
{
	lua_register(L2,"MyYield",luaMyYield);
}

void RegisterLuabind()
{
	module(L2)
	[
		def("MyYield", MyYield)
	];
}

int main()
{
	lua_State* L = lua_open();
	luabind::open(L);
	luaL_openlibs(L);

	L2 = lua_newthread (L);

	RegisterLuabind();	// ******************************
	//RegisterLua();		// ******************************

	int error = luaL_dofile(L2,"hello.lua");
	if (error != 0)
	{
		if(lua_isstring(L2, -1))
		{
			const char* err = lua_tostring(L2, -1);
			cout << err << endl;
		}
		return -1;
	}
	lua_getglobal(L2, "mythread");
	lua_resume(L2,0);

	while(1)
	{
		cout << "please input ... " << endl;
		string s ;
		cin >> s;
		if (s == swait)
		{
			cout << "in main input " << s << endl;
			lua_resume(L2,0);
			if (s == "quit")
				break;
		}
		else
		{
			cout << "not match input" << endl;
		}
	}
}

	and the hello.lua file

function mythread()
	print "need yield"
	MyYield("yield")
	print "need quit"
	MyYield("quit")
end


	it works well as: 

	need yield
	thread is waiting for yield
	please input ... 
	yield  // keyboard input
	in main input yield
	need quit
	thread is waiting for quit
	please input...
	quit   // keyboard input

	all are ok!
	but if  comment RegisterLuabind uncomment RegisterLua

	//RegisterLuabind();	// ******************************
	RegisterLua();		// ******************************
	
	need yield
	thread is waiting for yield	
	//skip the pre input...
	need quit
	thread is waiting for quit
	please input...
	quit   // keyboard input
	it crashed 	

	why?
	I had thought the RegisterLuabind and RegisterLua are the same
thing, but there are some magic beyond what I know :(

mos