Why does it crash?

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Originally Posted by Paul McKenzie

Because the C++ language specification says it's wrong (more precisely, undefined). You don't code an application that invokes undefined behavior.

Others may point to underlying code, but there is no need to. The C++ language spec clearly states that this is undefined behavior, regardless of what the underlying code may state. Even if it worked without crashing, you don't write code that does this.

Regards,

Paul McKenzie

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Of course, this pertains to the original code in the first post. The subsequent code had two errors, which I pointed out

a) wrong form of delete (which is undefined behavior)

b) changing the pointer value (which more than likely cause a crash, but not guaranteed to so).

Regards,

Paul McKenzie

Quote:

---

Originally Posted by Paul McKenzie

Because the C++ language specification says it's wrong (more precisely, undefined). You don't code an application that invokes undefined behavior.

Others may point to underlying code, but there is no need to. The C++ language spec clearly states that this is undefined behavior, regardless of what the underlying code may state.

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This is true, but I think dullboy was looking to try to understand why it would crash in a technical sense, not just because the standard says it is undefined. There is a reason the standard made this undefined; understanding the fundamental problem with what the code is trying to do can help to understand not only the problem at hand, but with other scenarios as well, without having to refer to the standard for each and every questionable line.