> For the complete documentation index, see [llms.txt](https://emacs-lisp.ivory.cafe/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://emacs-lisp.ivory.cafe/bian-liang/untitled-3/12.9.1-xian-zhi.md).

# 12.9.1 限制

由几种情况下，变量的改变并不会触发 watchpoint

因为 watchpoint 时绑定在符号上的，对于变量内部包含的对象的变化并不会触发监视机制。

此外，C code 可以直接修改一个变量，而不经过监视机制。

同样的原因导致的另外一个小限制是，只有动态绑定规则的变量可以被监视。这个解释起来也很简单，因为词法作用域的变量的变化可以很容易被任何代码觉察到。详情查阅 变量作用域章。


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