OpenSSL::BN.rand_range

static VALUE
ossl_bn_s_rand_range(VALUE klass, VALUE range)
{
    BIGNUM *bn = GetBNPtr(range), *result;
    VALUE obj = NewBN(klass);
    if (!(result = BN_new()))
        ossl_raise(eBNError, "BN_new");
    if (BN_rand_range(result, bn) <= 0) {
        BN_free(result);
        ossl_raise(eBNError, "BN_rand_range");
    }
    SetBN(obj, result);
    return obj;
}