Re: [boost] [shared_ptr] dangerous implementation of moveconstructor

From: Joe Gottman (jgottman_at_[hidden])
Date: 2007-04-16 19:15:50

Peter Dimov wrote:
> Ion Gaztañaga wrote:
> 
>> Ok. So if such objects can't be moved, there is no problem to offer
>> reusability for other objects that can be moved ;-)
> 
> Reusability was never questioned. Usability after move is the problem. The 
> question is whether the user may legitimately do something with an 
> moved-from object with predictable results _except_ destroying or reusing it 
> via assignment or reset. 
> 
>

    There are many more ways to reuse an object than assignment and 
reset.  For instance, I would be extremely disappointed if the following 
code didn't work:

vector<double> foo;
vector<double> bar = move(foo);
foo.resize(10);
for (size_t n = 0; n < 10; ++n) {
      foo[n] = n + 7;
}

Joe Gottman