OpenSSL::BN.generate_prime

static VALUE
ossl_bn_s_generate_prime(int argc, VALUE *argv, VALUE klass)
{
    BIGNUM *add = NULL, *rem = NULL, *result;
    int safe = 1, num;
    VALUE vnum, vsafe, vadd, vrem, obj;

    rb_scan_args(argc, argv, "13", &vnum, &vsafe, &vadd, &vrem);

    num = NUM2INT(vnum);

    if (vsafe == Qfalse) {
        safe = 0;
    }
    if (!NIL_P(vadd)) {
        add = GetBNPtr(vadd);
        rem = NIL_P(vrem) ? NULL : GetBNPtr(vrem);
    }
    obj = NewBN(klass);
    if (!(result = BN_new())) {
        ossl_raise(eBNError, NULL);
    }
    if (!BN_generate_prime_ex(result, num, safe, add, rem, NULL)) {
        BN_free(result);
        ossl_raise(eBNError, NULL);
    }
    SetBN(obj, result);

    return obj;
}