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Yes. Undefined behavior exists only in standards. It's perfectly possible for implementations to define everything.

https://www.joelonsoftware.com/2004/06/13/how-microsoft-lost...

> I first heard about this from one of the developers of the hit game SimCity, who told me that there was a critical bug in his application:

> it used memory right after freeing it, a major no-no that happened to work OK on DOS but would not work under Windows where memory that is freed is likely to be snatched up by another running application right away.

> The testers on the Windows team were going through various popular applications, testing them to make sure they worked OK, but SimCity kept crashing.

> They reported this to the Windows developers, who disassembled SimCity, stepped through it in a debugger, found the bug, and added special code that checked if SimCity was running, and if it did, ran the memory allocator in a special mode in which you could still use memory after freeing it.



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