[Development] RFC: more liberal 'auto' rules?

Olivier Goffart olivier at woboq.com
Mon Dec 7 17:53:41 CET 2015

On Monday 7. December 2015 08:28:53 Thiago Macieira wrote:
> What const is missing? Are you saying it should have been
> 	for (const std::pair<const std::string, std::string> &e: stdMap)


The value_type of a std::map<Key,T>  is std::pair<const Key, T>.

It allows to do this:

   // add "foobar" to all the entries
   for (auto &e: stdMap)
         e.second += "foobar";

But it does not allow to change the key because that cannot be changed via an 

> If so, I consider that an API defect in std::map 

Quite the contrary.

> or an implementation defect in std::string in the first place. It wouldn't
> cause a magnitude of performance difference if they were implicitly shared,
> like QString.

That's another issue.


Woboq - Qt services and support - http://woboq.com - http://code.woboq.org

More information about the Development mailing list