, <b>BN_GENCB_call(cb, 1, -1)</b> is called.</p>

<p>After each round of the Miller-Rabin probabilistic primality test, if <b>cb</b> is not <b>NULL</b>, <b>BN_GENCB_call(cb, 1, j)</b> is called with <b>j</b> the iteration (j = 0, 1, ...).</p>

<p>BN_GENCB_call() calls the callback function held in the <b>BN_GENCB</b> structure and passes the ints <b>a</b> and <b>b</b> as arguments. There are two types of <b>BN_GENCB</b> structure that are supported: &quot;new&quot; style and &quot;old&quot; style. New progr