Re: [boost] Pimpl Again?

Subject: Re: [boost] Pimpl Again?
From: Howard Hinnant (howard.hinnant_at_[hidden])
Date: 2016-05-31 21:57:32

On May 31, 2016, at 9:51 PM, Vladimir Batov <Vladimir.Batov_at_[hidden]> wrote:
> 
> On 2016-06-01 11:08, Howard Hinnant wrote:
>> ...
>> It has to be outlined, in the source.cpp:
>> ...
>>    Book::~Book() = default;
>>    Book::Book() = default;
> 
> Uh, yes, indeed. I got it now. I'll adjust the wording in the docs.

Excellent, thanks.

> 
> Somewhat off the topic.
> 
> From efficiency point of view the above is identical to
> 
> Book::~Book() {}
> 
> or compiler writers do more magic with "=default"? I like "=default" as I feel it's cleaner language-wise. What weighty reason can I give to a beginner to prefer "=default" over {}... apart from "I am older, musclier and your boss" :-)

That’s a good question.  It doesn’t turn the destructor from non-trivial to trivial.  It does not change the noexcept or constexpr status.  The only thing it really does is say:  I want default semantics here.  Maintenance programmers should be more leery of adding superfluous stuff to your destructor.

Howard