Re: [Boost-users] revisiting casting a boost::shared_ptr to void*

Subject: Re: [Boost-users] revisiting casting a boost::shared_ptr to void*
From: Michael Powell (mwpowellhtx_at_[hidden])
Date: 2014-07-29 12:30:08

On Tue, Jul 29, 2014 at 11:25 AM, Chris Cleeland
<chris.cleeland_at_[hidden]> wrote:
>
>
>
> On Tue, Jul 29, 2014 at 11:02 AM, Michael Powell <mwpowellhtx_at_[hidden]>
> wrote:
>>
>> Along the lines what Edward suggested, if the "origin" of the pointer
>> is your thread, then somehow you need to make sure that memory lives
>> beyond the lifetime of the external, in this case C, API, context and
>> all, etc, etc. No room for debate in that topic; it is what it is,
>> deal with it in a responsible manner.

The C API is not managing the life time of the instance allocated to
the shared_ptr. When the shared_ptr<> falls out of scope, all bets are
off. Plain and simple.

> Yes, I agree that I'm responsible.  If I didn't know or think that, then I
> wouldn't have asked the question in the first place.
>
> I'm not debating whether or not I *should* be responsible--I'm asking a
> question related to best-practices for fulfilling that responsibility in the
> absence of the ability to use a shared pointer and its concomitant semantics
> everywhere the pointer is held. While I appreciate your response and
> Edward's response, neither answers the question asked.
>
> Thanks to Dominique for sharing a technique.  I hadn't thought of using a
> heap-allocated shared pointer instance as the proxy.  I had thought of
> stashing another shared pointer instance in the C++ object that manages the
> callback registration itself, but wasn't sure if that lifecycle would
> coincide exactly.  The heap is probably the better of the two since it
> dissociates all lifecycles.
>
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