RE: [lwip-users] tcp_write and dynamic data (was: Optimizing TCP writes)

[Kieran Mansley]

On Fri, 2008-03-07 at 09:55 -0500, Bill Auerbach wrote:
> Jonathan,
> 
> While debugging this, I found a much more serious problem to now deal with.
> Once resolved, I'll continue on the original problem because I don't want to
> have this new problem be causing the original.
> 
> In my tcp_sent callback, I see that I have no remaining data to send.  It
> was recommended that this is the time that I can deallocate the memory
> passed to tcp_write (because presumably it's been sent).  The problem is,
> this data is still in the send queue and cannot be deallocated at this time.
> The data cannot be deallocated until it is ACKed, which I have no way of
> knowing (I think).

tcp_sent callback should not be called until the data are ACKed.  If
it's still in the send queue there's a bug.

Kieran