Re: [boost] [smart_ptr] Is there any interest in unique_ptr with type erased deleter?

Subject: Re: [boost] [smart_ptr] Is there any interest in unique_ptr with type erased deleter?
From: TONGARI J (tongari95_at_[hidden])
Date: 2017-03-21 08:10:29

2017-03-21 15:04 GMT+08:00 Andrey Davydov via Boost <boost_at_[hidden]>:
[...]

> I have implemented smart pointer with semantics of unique ownership and
> type erased deleter (https://github.com/AndreyG/unnamed). It has size of 3
> pointers and it doesn't require additional memory allocations for the case
> when deleter is empty class (for example, std::default_delete or
> non-capturing lambda) and for the case when deleter is known at compile
> time function (for instance, fclose). The are some simple examples of usage
> and tests in the repo.
>
> Why don't just use unique_ptr<T, function<void (void *>>? The main reason
> is that due to the small object optimization std::function has rather big
> size. For instance, sizeof(unique_ptr<T, function<void (void *>>) == 72 for
> MSVC x64! Results for the other platforms can be found in the repo README.
>
> Does it seem useful?
>

Why not:
```
template<class T>
using my_ptr = unique_ptr<T, void(*)(T*)>;
```
? Even if you need a stateful deleter, you don't need to reinvent the whole
unique_ptr, just use your custom type-erased deleter.