Re: [Boost-users] Boost::asio - how to detect if a remote sockets client has disconnected

Subject: Re: [Boost-users] Boost::asio - how to detect if a remote sockets client has disconnected
From: Jonathan Franklin (franklin.jonathan_at_[hidden])
Date: 2009-07-25 15:56:07

On Sat, Jul 25, 2009 at 1:42 PM, Scott Gifford<sgifford_at_[hidden]> wrote:
> If the client just disappears, you won't get any
> notification until you try to send data (including the OS sending TCP
> Keepalives, if they are enabled); then when that data send times out,
> you will get an error, probably on your read or the next time you try
> to write.

If the client silently drops off, I wouldn't count on getting an error
from send until your TCP send buffer fills up.  Depending on how large
the request file/resource is, you may never know that the client
dropped off.  Writes basically always succeed if there is space in the
buffer.  If the response fits in the buffer, you'll write, close the
socket, and never get an error.  If the response is larger than the
buffer, you'll fill up the buffer, block (assuming blocking io) until
the send times out, and then possibly get an error (dependent on your
TCP stack impl).

Jon