版本兼容性问题：使用 gc_mem_caches 函数时你需要注意什么？

<span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 前言部分示例代码，与文章内容无关</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"欢迎使用PHP教程示例！<br>"</span></span><span>;
</span><span><span class="hljs-variable">$version</span></span><span> = </span><span><span class="hljs-title function_ invoke__">phpversion</span></span><span>();
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"当前PHP版本为：<span class="hljs-subst">$version</span></span></span><span><br>";

</span><span><span class="hljs-comment">// 一些无关的辅助函数</span></span><span>
</span><span><span class="hljs-function"><span class="hljs-keyword">function</span></span></span><span> </span><span><span class="hljs-title">greet</span></span><span>(</span><span><span class="hljs-params"><span class="hljs-variable">$name</span></span></span><span>) {
    </span><span><span class="hljs-keyword">return</span></span><span> </span><span><span class="hljs-string">"Hello, <span class="hljs-subst">$name</span></span></span><span>!";
}
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-title function_ invoke__">greet</span></span><span>(</span><span><span class="hljs-string">"开发者"</span></span><span>);
</span><span><span class="hljs-meta">?></span></span><span>

<hr>

</span><span><span class="hljs-meta"><?php</span></span><span>
</span><span><span class="hljs-comment">// 正文开始</span></span><span>
</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<h2>版本兼容性问题：使用 gc_mem_caches 函数时你需要注意什么？</h2>"</span></span><span>;

</span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"<p>在PHP中，<code>gc_mem_caches()