Avoid automatic copy constructor generation

[Juha Nieminen]

How do you handle reference members?

In the exact same way as currently?

 

[Bo Persson]

Well - i certainly hope so ;-)


I agree - that would not be possible. But can I sidestep a little
and be off-topic for a second? I really like the idea of having a
copy- constructor being default being defined explicitly with the
new syntax, and now I wonder if there has been any proposal to
expand on the default stuff, notable for swap.
As the user-defined copy-constructor really is error-prone (I have
been bitten once or twice by forgetting the copying when adding a
new member to a class), I do my best to make sure that the default
constructor (and assignment-operator) works and normally restrict my
userdefined constructors to small classes with less than a handfull
of membervariables. But swap is another matter: I normally don't
write a swap function and live with the lost performance,
correcting the problem when e.g. I wind up with sorting large
arrays of those objects. But wouldn't it be nice if you could
write void swap(my_class& other) = default as well?
In other words: has there been any proposal to provide this
functionality in some later version of C++? I have skimmed the docs
but found nothing like that in C++0x. I do not know how general it
could be: having "= default" creating a function with standard
functionality for each member-variable (causing an error when that
functionality is not available) would be nice indeed.

No, I haven't seen anything like that either.

On the other hand, the standard swap function will attempt a
move-construction of your objects, instead of a copy-construction and
destruction of a temporary. That might improve things enough that you
need fewer specialized swaps.


Bo Persson

 

[Juha Nieminen]

I agree - that would not be possible.

And not what I suggested in the first place.