# 2.4.20 终止类型

终止类型对象会协助lisp 代码做一些清理工作，尤其是当某个对象不在被需要的时候。终止对象会储存一个函数对象。在垃圾清理后，终止对象不被任何方式引用时，Emacs会调用终止对象相连的函数对象。在计算引用时，Emacs不会记录终止对象的引用，因此你可以放心的使用终止对象。

终止对象引发的错误会被输出到 \*Messages\* 中。Emacs只会运行一次终止对象相连的函数，即便函数调用失败。

Function: make-finalizer function\
  生成一个终止对象，这个终止对象的关联函数为 function。当终止对象不可用时，其关联的函数便会被调用。如果一个终止对象引用了另一个终止对象，那么这个引用不会被计数。每个终止对象只会运行一次关联函数。


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