From: Stephen Hemminger <shemminger@vyatta.com>
To: Rick Jones <rick.jones2@hp.com>
Cc: Paul Martin <srucnoc@gmail.com>, netdev@vger.kernel.org
Subject: Re: TCP partial write
Date: Mon, 15 Jun 2009 10:26:55 -0700 [thread overview]
Message-ID: <20090615102655.5059302d@nehalam> (raw)
In-Reply-To: <4A368049.7080903@hp.com>
On Mon, 15 Jun 2009 10:09:29 -0700
Rick Jones <rick.jones2@hp.com> wrote:
> Paul Martin wrote:
> > Is it possible that a (non-blocking) TCP write(2) will write a number
> > of bytes not multiple of the machine word size? i.e., could a write
> > request for 4 bytes return 2?
>
> Yes.
>
> > Also is this an OS-dependent behavior or there is a spec for it? (I
> > could find atomic guarantees for pipes and datagram sockets but not
> > for TCP)
>
> TCP is a byte-stream. It sends and receives a stream of bytes. You should/must
> assume that when you do a non-blocking write, it will take any number of the
> bytes you offer from 0 to however many bytes you give it. And you should/must
> assume that at the other end, your recv/read calls will return with between 0 and
> however many bytes you ask of them, with 0 meaning the remote has said it has
> nothing left to give.
>
Actually on a blocking socket 0 means other end has closed.
next prev parent reply other threads:[~2009-06-15 17:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-14 19:52 TCP partial write Paul Martin
2009-06-15 17:09 ` Rick Jones
2009-06-15 17:26 ` Stephen Hemminger [this message]
2009-06-15 17:59 ` Rick Jones
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