Segfault when trying to call lua functions defined in a table

Question

I am trying to solve this seg fault problem, arised when a lua function defined in a table is called from C++ using luabind. Here is C++ the code (borrowed from In C++, using luabind, call function defined in lua file?, and http://lua.2524044.n2.nabble.com/How-to-call-a-Lua-function-which-has-been-defined-in-a-table-td7583235.html ):

extern "C" {
#include <lua5.2/lua.h>
#include <lua5.2/lualib.h>
#include <lua5.2/lauxlib.h>
}


#include <iostream>
#include <luabind/luabind.hpp>
#include <luabind/function.hpp>

int main() {
    lua_State *myLuaState = luaL_newstate();
    luaL_openlibs(myLuaState);
    luaL_dofile(myLuaState, "test.lua");
    luabind::open(myLuaState);

    luabind::object func = luabind::globals(myLuaState)["t"]["f"]; // Line #1
    int value = luabind::call_function<int>(func, 2, 3); // Line #2
    std::cout << value << "\n";
    lua_close(myLuaState);
}

and here is the lua code:

t = { f = function (a, b) return a+b end }   -- Line #3

The program is compiled with

g++ test.cpp -I/usr/include/lua5.2 -llua5.2 -lluabind

The output of the cpp program is

5
Segmentation fault (core dumped)

with the backtrace:

#0  0x00007ffff7bb0a10 in lua_rawgeti ()
   from /usr/lib/x86_64-linux-gnu/liblua5.2.so.0

#1  0x00007ffff7bc27f1 in luaL_unref ()
   from /usr/lib/x86_64-linux-gnu/liblua5.2.so.0

#2  0x0000000000401bb5 in luabind::handle::~handle() ()

#3  0x0000000000401e15 in luabind::adl::object::~object() ()

#4  0x000000000040185c in main ()

However, I don't see any error if the lua function is instead defined as a global, i.e change line #3 to read

f = function (a, b) return a+b end

and line #2 is changed to

int value = luabind::call_function<int>(myLuaState, "f", 2, 3);

So my question is:

• Why is this happening?

• Is this the correct way to call functions in a table?

Per @EtanReisner comment, the correct solution is:

Putting the call_function part in a scope block would solve this problem.