From: Peter Dimov (pdimov_at_[hidden])
Date: 2005-06-27 16:33:10
David Abrahams wrote:
> "Peter Dimov" <pdimov_at_[hidden]> writes:
>
>>> Yes. Why wouldn't you want this function to require that condition?
>>> Anything else is a coding error.
>>
>> I am reluctant to label it a coding error ("should never happen in a
>> correct program"), because in general it can be very hard to ensure
>> that the condition isn't violated. It's a bit like:
>>
>> Requires: a particular state of the library that you have no way of
>> querying.
>
> Harrumph. Isn't it the archive under construction whose state is
> constrained? If you know you've put 5 elements in a vector, you don't
> have to query it before calling pop_back(), do you?
So it's safe to remove size() and empty() from the vector interface as users
always know how large their vectors are, right?
If you are given a vector you don't know whether you can pop_back.
If you are given an archive you don't know whether you are allowed to save
by value, or whether you can safely save by pointer.
(In general.)