Re: UB while dealing with invalid raw pointers, the std::uninitialized_fill case
Stuart Redmann wrote:
On 3 Sep., Francesco S. Cartawrote:
Would all the above mean that we shouldn't really worry about UB
when dealing with invalid pointers into standard containers as
long as we don't dereference such invalid pointers, and
accordingly, would that mean that the standard needs to be
modified to state these actions (copying and comparing of invalid
pointers) as well-defined?
Stuart Redmann wrote:
I would rather like it if the standard made it some kind of
platform- dependent. Since nobody can cite some convincing
rationale for UB, and apparently lots of people use deleted
pointer in containers, it makes little sense to say that all
those programs show UB.
On 3 Sep., Bo Persson wrote:
You can't test for UB, because it IS undefined. "Seems to work"
isn't good enough! :-)
I don't quite get you. What do you mean by "testing" for UB? "Seems
to work" is good enough for me when the compiler emits the right
binary (if the produced binary is well-formed, I don't need to care
whether the compiled source code is ill-formed).
I mean running unit tests for your code.
Because the UB doesn't have to be consistent, passing the tests
doesn't tell us if the code works, just that it works sometimes.
"Seems to work".
UB is really evil!
Bo Persson
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