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A comment on C pointers are not hardware pointers. Parent comment

Re:C pointers are not hardware pointers by dave2000 on Monday March 07, 2016 @05:53AM (#11238179)
I don't see how comparing the value of a pointer, the area of memory to which it points having been previously freed, is undefined behaviour. Is there a source in the spec for this?
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Re:C pointers are not hardware pointers by belovedeagle on Wednesday March 09, 2016 @12:33AM (#11251132)
Yes, it's in the article.

> I don't see how [. . .] is undefined behaviour.

This is a perfectly meaningless sentence. "Undefined behavior" doesn't mean "things which don't make sense in a particular implementation", it literally means behavior not defined by the spec. The spec declines to define the meaning of p==q when p and/or q is a freed pointer. There's nothing to "see" here: it's just not defined.

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