Re: [lwip-users] Question about thread safety

[Simon Goldschmidt]

Louis Wells wrote:

> I have a thread set up for tcpip, and another thread that is running a sort 
> of main lwip task, which is used to determine whether or not my board is 
> plugged into a network and use dhcp, or if no network is accessible and my 
> board should act as a server to dole out an ip address to a directly 
> connected laptop. 

I'm not sure I fully understand your threading setup, but maybe it helps if I 
repeat on lwIP's threading requirements:

- only a specific subset of the functions may be called from another thread 
than tcpip_thread
- As you said, when accessing internal functions from another thread, you must 
use tcpip_callback.
- especially the raw API functions (tcp.h, UDP.h, etc) must not be called from 
other threads.
- callback functions from the raw api are always called from tcpip_thread by 
lwIP, so you can call into the stack without tcpip_callback from there.

Hope that helps.

Simon