Re: [boost] [smart_ptr] enable_shared_from_this and shared_ptr to a base class

Subject: Re: [boost] [smart_ptr] enable_shared_from_this and shared_ptr to a base class
From: Jonathan Wakely (jwakely.boost_at_[hidden])
Date: 2013-06-24 05:03:09

On 24 June 2013 09:37, Andrey Semashev wrote:
> On Mon, Jun 24, 2013 at 12:06 PM, Jonathan Wakely
>>
>> I think there is a small documentation bug though,
>> enable_shared_from_this talks about owning an object of type T, but
>> the shared_ptr docs talk about owning a pointer.  The docs for
>> std::enable_shared_from_this correctly say "There shall be at least
>> one shared_ptr instance p that owns &t." (as opposed to "owns t").
>> The & should be added to the Boost docs.
>>
>
> I think it is more correct to say "the pointer owns the [pointed to]
> object" rather than "the pointer owns the pointer to the object". If the
> citation you quoted is taken from the standard, then it probably should be
> corrected.

No, please read the shared_ptr specification before deciding what
should be corrected, it is very clear in the Boost docs and the
standard: "constructs a shared_ptr that owns the pointer p."

That is not a mistake.  If I construct shared_ptr<T>((T*)0, D()) then
it owns a null pointer and will invoke the deleter D on the null
pointer. That has well-defined semantics and you can't do that if it
has to own an object rather than a pointer.