Re: [Boost-users] Concurrency and session termination in boost::asio

Subject: Re: [Boost-users] Concurrency and session termination in boost::asio
From: Scott Gifford (sgifford_at_[hidden])
Date: 2008-11-06 10:41:02

"Igor R" <boost.lists_at_[hidden]> writes:

>> Does all of that sound about right?
>
> Yes, that's exactly the way it's done in the examples.

Great, thanks!

>> The close method calls "is_open" to determine if the socket has
>> already been closed, and if it is not asks the OS to close it.
>>
>> It looks to me like this is not done in a threadsafe way.
>
> Right, you should post closing to the io_service thread, like this:

Ah, I see, thanks for the sample code!

I'm not sure I understand exactly what makes this threadsafe, though.
It seems like if my reader callback and writer callback are running
simultaneously, and both decide to close the connection, they will
post two close requests to io_service.  If those requests are
scheduled on two different worker threads, they could execute
simultaneously, and still cause problems.

> void my_connection::do_close()
> {
>   boost::system::error_code err;
>   socket_.close(err);
> }

Maybe I should just hold a lock in do_close?  That seems like it would
solve the problem.

Thanks again for the help!

-----Scott.