std::string::reserve()

[Paolo Carlini]

Neil Ferguson wrote:

> I've attached diffs against latest CVS that try to avoid doing
> this, and I'd be interested to know what you think.

Hi Neil, thanks for your message. A few observations:

1- If you plan contributing patches of this size you definitely need a
   copyright assignment on file:

     http://gcc.gnu.org/contribute.html

2- Your change definitely makes sense but not calling _M_clone has
   a not-completely-obvious effect: if the string is in the leaked
   state it remains leaked, doesn't become sharable. Perhaps you
   want to return early only if the string is already sharable?
   A leaked string cannot be refcopied and avoiding the _M_clone
   call could imply having to call it *many* times later in an
   assign, in a constructor or what else...

3- Please, please strive to have a working regtesting setup. It's
   important not only to spare us the task (that's not a big deal)
   but also when fixing bugs or envisaging large scale changes...

Paolo.