Re: [lwip-users] questions (help and advice needed)

[Kieran Mansley]

On Sun, 2010-11-28 at 16:31 -0500, shogun wrote:
> In the most simple terms, my question is if I use the RAW API, do I
> need two
> tasks for the lwip stack as described in section "12.2 Implementation
> of the
> API" of the document "Design and Implementation of the lwIP. TCP/IP
> Stack".
> It's not clear to me what goes in what context with and without a
> RTOS.

The golden rule is that only one thread should be active in lwIP.  The
way this is normally achieved with an OS is to have a thread that is
dedicated to lwIP - this is often referred to as the tcpip thread.  The
driver will pass received packets to the tcpip thread by queueing them
and setting a flag for example.  The application must do something
similar.  The netconn API is one example of how to do this and might be
the easiest way for you, but you can also do it with the raw API.  You
just have to make sure you get into the context of the tcpip thread to
do any lwIP actions.  E.g. by using the tcpip_callback() function.

Kieran