双malloc的行为自由 [英] malloc double free behaviour

问题描述

为的malloc 的GNU手册页定义，当免费（）使用同一指针调用两次（这是$ p $由 pviously分配的malloc（））出现未定义的行为。

The GNU manual page for malloc defines that when free() called twice with the same pointer (that was previously allocated by malloc()) "undefined behaviour occurs".

什么样的​​行为是什么？结果
我在哪里可以找到这种类型的错误的更多信息？

What kind of behaviour is that?
Where can I find more Information about this kind of error?

推荐答案

未定义行为，只是意味着实现不需要处理任何特殊方式的情况;的任何的行为或结果被认为是正确的。

"Undefined behavior" simply means that the implementation isn't required to deal with the situation in any particular way; any behavior or result is considered "correct".

免费的-ing不止一次指针的结果是达到的malloc 的底层实现;其结果可能是一个崩溃和核心转储，也可能损坏的malloc 舞台（污损了未来分配/释放操作），或者它可能忽略双免费完全。

The result of free-ing a pointer more than once is up to the underlying implementation of malloc; the result could be a crash and core dump, or it could corrupt the malloc arena (fouling up future allocations/deallocations), or it could ignore the double free entirely.

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