c++ - 为什么 C++ 编译器不立即删除超出生命周期的变量？

Question

来自 Scope vs. Lifetime of Variable我们看到了来自 Alok 的 anser 部分:

Note that technically x does not exist beyond its scope however it might happen that the compiler did not remove the contents of x and one might be able to access contents of x beyond its scope through a pointer(as you do).However, a code which does this is not a valid C++ code. It is a code which invokes Undefined Behaviour. Which means anything can happen(you might even see value of x being intact) and one should not expect observable behaviors from such a code.

这很有趣。为什么不在变量 x 到达 } 时将其删除？

Answer 1

同理删除硬盘上的文件，为什么只是删除索引项而不是格式化文件？
这需要时间。

如果没有必要，删除内存是没有意义的。稍后当您创建另一个局部变量时，编译器将再次使用该内存块，但在此之前它只会忽略内容。