Re: [lwip-devel] [task #7865] implement non-blocking SEND operation (socket)

[latkinso42]

Doug,
I am very much interested in a solution to the non-blocking issue for a
write (send).
My buffer is perhaps 180+ in size holding an http GET request. No way to
make it smaller.
Currently the max buffer, TCP_SND_BUF, is 265 in opt.h and the TCP_SNDLOWAT
is half that.
The write (lwip_write or lwip_send) is returning an err = 248 which is the
buffer size. I can make it somewhat smaller, but no small er than 180. Can I
send part of buffer with multiple write until done or 
do you have a techniques that works and does not block?
Lee
 

Doug Simons-3 wrote:
> 
> 
> Update of task #7865 (project lwip):
> 
>                   Status:                    None => Ready For Test         
>         Percent Complete:                      0% => 90%                    
>              Assigned to:                    None => goldsimon              
> 
>     _______________________________________________________
> 
> Follow-up Comment #7:
> 
> As described in last comment, I've added nonblocking write (for netconn
> and
> sockets). Once such a nonblocking write failed, sent_tcp and poll_tcp will
> check if there's enough buffer and mark the socket writable again.
> 
> Also, lwip_send() checks if the data would ever fit into the buffers and
> returns EMSGSIZE if not - I'm not sure what's the correct error here...
> 
> There's one lwIP-related problem: when a nonblocking write fails and
> poll_tcp
> marks the socket writable again, the next call could fail again if 'size >
> TCP_SNDLOWAT' (because TCP_SNDLOWAT is used when marking the socket
> writable).
> I don't know how other stacks solve this, but for us, the next call to
> write
> would return EAGAIN again.
> 
>     _______________________________________________________
> 
> Reply to this item at:
> 
>   <http://savannah.nongnu.org/task/?7865>
> 
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