Re: [RFC] Using std::unique_ptr and std::make_unique in our code

[Jonathan Wakely <jwakely.gcc@gmail.com>]

On Tue, 12 Jul 2022 at 11:22, Florian Weimer via Gcc <gcc@gcc.gnu.org> wrote:
>
> * Pedro Alves:
>
> > For example, for the type above, we'd have:
> >
> >   typedef std::unique_ptr<pending_diagnostic> pending_diagnostic_up;
> >
> > and then:
> >
> >  -                                pending_diagnostic *d,
> >  +                                pending_diagnostic_up d,
> >
> > I would suggest GCC have a similar guideline, before people start
> > using foo_ptr, bar_unp, quux_p, whatnot diverging styles.
>
> This doesn't seem to provide much benefit over writing
>
>   uP<pending_diagnostic> d;
>
> and with that construct, you don't need to worry about the actual
> relationship between pending_diagnostic and pending_diagnostic_up.
>
> I think the GDB situation is different because many of the types do not
> have proper destructors, so std::unique_ptr needs a custom deleter.


A fairly common idiom is for the type to define the typedef itself:

struct pending_diagnostic {
  using ptr = std::unique_ptr<pending_diagnostic>;
  // ...
};

Then you use pending_diagnostic::ptr. If you want a custom deleter for
the type, you add it to the typedef.

Use a more descriptive name like uptr or uniq_ptr instead of "ptr" if
you prefer.