David Hammerton wrote:
closing a socket, whilest thread 1 is still using it for send/recv,
which causes a problem - as yes, that would be a problem in any socket
environment.
I think some socket environments support this. The result would be that
the send/recv call returns with an error message "socket closed".
So the send there would be happening on the TCP thread (as a result of
the message), is that safe to happen while you are reading on your
read/write thread anyway? It must be, as if your read/write thread
does a send() followed immedietly by a recv(), it's going to be the
same thing.
No, the send() finishes (data copied into tcp_raw buffers) before it
returns. The means the netconn's state reaches idle (or 'none' in the
code) so it's free to acept a recv().
Ok. A little while ago I had an lwIP app that was written using the
BSD socket layer, and this is exactly what I did. I had to modify the
select() call to be able to pass in another object (representing a
semaphore, really) that could be used to interrupt the select() call.
I couldn't see any way of creating a socketpair() like object to
interrupt the select() call. There is no built in way to do this with
the BSD socket layer in lwIP, correct?
Yeah, that's a point currently missing with the basic select()
implementation we have. Usually, you would just create a loopback socket
and trigger it, although that's rather unperformant, too.
But for the netconn layer, I guess I can do my own thing. Is this
(below)the correct way to do it?
Seems so, yes. Although there may be more arguments to your
netconn_calback() than RECV_PLUS.
Simon
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