Re: [Boost-users] enable_shared_from_this()

Subject: Re: [Boost-users] enable_shared_from_this()
From: John M. Dlugosz (mpbecey7gu_at_[hidden])
Date: 2013-02-07 11:42:09

Frank Mori Hess<fmh6jj_at_[hidden]>  wrote:

> That means
> throwing exceptions from the constructor after using shared_from_raw
> (or in any derived constructor since ithe derived constructor would be
> called later) causes bad things to happen.
That's no different from stashing away a raw pointer from a constructor (e.g. passing it 
as a "parent" pointer to a referenced object). But that could be improved upon: The 
collaborators can be given a weak_ptr only. But, we may require that collaborators have 
owning references. In my library, a "borrower" (weak_ptr) could optionally hold a strong 
reference as well, so the reference could be upgraded from weak to strong after a point of 
commitment is reached.

If there were some kind of on-spec pending ptr type, they could be seen as strong 
references eventually and in normal use, but automatically cleared or committed by the 
Create wrapper. That is, you would not have to keep track of the collaborators and hook 
them up in a second stage; rather, all such pending ptrs would become solid (wherever they 
are) with one call made after the ctor is golden.

I never had a problem with it, though.

—John