Hi what's the meaning of ~0 in this code????
somebody can analysis this code for me?

unsigned int     Order(unsigned int maxPeriod = ~0) const
                    {
                        Point r = *this;
                        unsigned int n = 0;
                        while( r.x_ != 0 && r.y_ != 0 )
                        {
                            ++n;
                            r += *this;
                            if ( n > maxPeriod ) break;
                        }
                        return n;
                    }

please help me soon....