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

[Pedro Alves]

On 2022-07-12 11:45 a.m., Jonathan Wakely wrote:
> 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.
> 

Only works if you can change the type, though.  Sometimes you can't,
as it comes from a library.