Re: [lwip-users] netconn_write/recv from two different tasks..

[Sylvain Rochet]

Hi Thomas,

On Wed, Mar 06, 2013 at 06:43:15AM -0800, ThomasJ wrote:
> Hi
> 
> Just an idea... and would it work?
> 
> If I keep my TX task and RX task.
> I then make make sure the TXTask does not use the netconn_write while the
> RXTask is in the netconn_recv call.
> Would that be ok or must the net connection be handle only by the same task?

I already told you about that. This is exactly the same thing from the 
lwIP point of view or generally speaking for any multithreading 
environment, this is not strictly lwIP-specific. The point is that 
netconn_ functions are not reentrant for -a- UDP or TCP control block, 
so serializing them through a mutex/semaphore from sparse threads will 
work.

But beware of dead locks conditions!, you are going to run a 
mutex/semaphore over a message passing system which of course cause 
contexts switchs (so priority reordering), this requires strict checking 
of any possible locking cases between 3 threads, a mutex/semaphore, and 
a mbox.

Sylvain