? symbols from LUA
===

I've registered LUA api function by using:

    lua_register( luaState, "someFunc", aaa::someFunc);

this function has to load a string from the someFunc's argument.

I am doing it with:

    int aaa::someFunc {
        char* _arg = ( char* )lua_tostring( state, -1 );

        // ...

        return 0;
    }

it works ok, until I put to someFunc() some symbols of my language like: ą, ł, ź etc (it's 'a', 'l', 'z' written holding ALT key). For these symbols it returns me only "?" for them all. How to recognize these values in my program?

Thanks.