#include <stdio.h>
#include "lua.h"
#include "lualib.h"
#include "lauxlib.h"


/* the Lua interpreter */
lua_State* L;

int luaadd ( int x, int y )
{
    int sum;

    /* the function name */
    lua_getglobal(L, "add");

    /* the first argument */
    lua_pushnumber(L, x);

    /* the second argument */
    lua_pushnumber(L, y);

    /* call the function with 2
     arguments, return 1 result */
    lua_call(L, 2, 1);

    /* get the result */
    sum = (int)lua_tointeger(L, -1);
    lua_pop(L, 1);

    return sum;
}

int main ( int argc, char *argv[] )
{
    int sum;

    /* initialize Lua */
    L = lua_open();

    /* load Lua base libraries */
    luaL_openlibs(L);

    /* load the script */
    luaL_dofile(L, "add.lua");

    /* call the add function */
    sum = luaadd( 10, 15 );

    /* print the result */
    printf( "The sum is %d\n", sum );

    /* cleanup Lua */
    lua_close(L);

    /* pause */
    printf( "Press enter to exit..." );
    getchar();

    return 0;
}


-- add two numbers

function add ( x, y )
    return x + y
end

#gcc luaadd.c -llua -ldl -o luaadd