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Subject: Re: [Boost-users] Why cannot asio tcp socket server detect TCP disconnection when the client device lost power?
From: jupiter (jupiter.hce_at_[hidden])
Date: 2017-06-30 11:21:19

On Fri, Jun 30, 2017 at 10:31 AM, Leon Mlakar via Boost-users <
boost-users_at_[hidden]> wrote:

> For monitoring your session you should use map/any_container with
>> weak_ptrs, not shared_ptrs.
> Interesting, I haven't thought that, what will be the issues and
> consequences to use shared_ptrs not weak_ptrs? Thanks for your advice.
> Shared pointers keep objects in existence, weak pointers don't. At a price
> of an additional lock() operation, of course (which, except in really time
> critical applications, should not be an issue).
> It's never a good idea to have too many shared pointers around, especially
> not in the monitoring maps as they may keep objects alive longer than
> intended.
> Additional advantage of using weak pointer in monitoring maps is that if
> the lock() fails it's okay to remove the entry from the map as the object
> is no longer there.
> Now, for the sake of being thorough - although weak pointer will not keep
> the object in existence, it will keep it's shared count alive. Which, in
> the case of using std::make_shared to allocate shared count and object
> memory in a single block, will keep the entire block of memory allocated
> until the last weak pointer is gone ... hence even in the case of using
> weak pointers it is a good idea to do occasional cleanup, which is rather
> trivial via failed lock()

Thanks for the explanation, I have more work to do :-) Cheers

> Cheers,
> Leon

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