eturn;
    }
    s = (size_t)m + (size_t)n;
}</pre>
<p>在《<a href="https://developer.apple.com/library/ios/documentation/Security/Conceptual/SecureCodingGuide/SecureCodingGuide.pdf" target="_blank" rel="noopener noreferrer">苹果安全编码规范</a>》（PDF）中，第28页的代码中：</p>
<p><img decoding="async" loading="lazy" class="aligncenter size-full wp-image-11472" src="/uploads/2014/04/apple_security_code.jpg" alt="" width="300" height="94" srcset=""/></p>
<p>如果n和m都是signed int�