Interrupt and restart running Lua

script.lua

print('Lua script is running...')
local x = 0
for i = 1, 10000000000 do
    local y = getNumber() -- C function
    x = x + y
end
print(x)

wrapper.cpp

// C++11
// Compile on Debian Wheezy:
// g++ -std=c++11 wrapper.cpp -o wrapper.exe \
//    -llua5.1 -I /usr/include/lua5.1/ -pthread

#include <cstdlib>
#include <cstdio>
#include <ctime>
#include <thread>

#include <lua.hpp>

enum {
    STATE_NORMAL,
    STATE_RESTART,
    STATE_STOP
};

int state = STATE_NORMAL;

int getNumber(lua_State* L) {
    if (state != STATE_NORMAL) {
        return luaL_error(L, "Interrupted");
    }
    // return random number
    int value = std::rand();
    lua_pushinteger(L, value);
    return 1;
}

void luaRunner() {
    // this code is run in other thread
    while (state != STATE_STOP) {
        state = STATE_NORMAL;
        lua_State* L = luaL_newstate();
        luaL_openlibs(L);
        // bind function getGlobal
        lua_pushcfunction(L, getNumber);
        lua_setglobal(L, "getNumber");
        // run script.lua
        int error = luaL_dofile(L, "script.lua");
        lua_close(L);
    }
}

int main() {
    std::srand(std::time(NULL));
    std::thread thread(luaRunner);
    printf("Lua works in other thread\n");
    while (state != STATE_STOP) {
        printf("Type 1 to restart Lua, 2 to stop Lua.\n");
        int input;
        scanf("%d", &input);
        if (input == 1) {
            state = STATE_RESTART;
            printf("Lua restarted!\n");
        }
        if (input == 2) {
            state = STATE_STOP;
            printf("Lua stopped!\n");
        }
    }
    thread.join();
}