Re: [Boost-users] Boost-users Digest, Vol 2933, Issue 5

Subject: Re: [Boost-users] Boost-users Digest, Vol 2933, Issue 5
From: Rory Hart (hartror_at_[hidden])
Date: 2011-12-13 04:48:09

Thanks Marat,

I am clear on the function and intention of stop and reset now, as I said
it helps that I have now RTFM.

I am not suggesting the handlers receive an error state, rather it is in a
case such as this:

boost::asio::io_service io_service;
io_service.stop();

// add a async read/write etc here

boost::system::error_code ec;
size_t count = io_service.run(ec);

The variable ec now has a success state which I don't think is accurate an
accurate representation of what happened when io_service::run is called on
a stopped io_service object.

What I am suggesting is in a case such as this an error should be set.

Thanks

Rory

On Tue, Dec 13, 2011 at 6:38 PM, Marat Abrarov <abrarov_at_[hidden]> wrote:

> Hi, Rory.
>
> > Is there a reason io_service::run does not set an appropriate error on
> the
> > passed boost::system::error_code object when this is encountered?
> Certainly
> > it seems like an error case and would help circuital circumstances such
> as
> > my own.
>
> With current behavior of asio::io_service we can continue working with
> io_service after it was stopped by calling
> asio::io_service::reset(). It's like pause on io_service. It's not often
> used feature but it is nice to know that such
> behavior is possible.
>
> Also note that invocation of handlers is done only within threads that
> executes asio::io_service::run (run_one, poll,
> poll_one -
> http://www.boost.org/doc/libs/1_48_0/doc/html/boost_asio/overview/core/threads.html
> ).
> When io_service switches to the "stopped" state asio::io_service::run have
> to exit as fast as possible.
> When io_service is already in the "stopped" state asio::io_service::run
> have to exit immediately.
> So if io_service is already in stopped state before any user thread calls
> asio::io_service::run how can Asio pass
> "appropriate error" to asynchronous completion handlers?
>
> IMHO, current design of Asio is very clear.
>
> Regards,
> Marat Abrarov.
>
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