Re: [lwip-users] Socket API thread safe?

[Leon Woestenberg]

Hello Wilfred,

Wilfred Hoogerbrugge wrote:
>
> As the subject already shows I wonder if the lwIP socket API is multi thread
> safe.
This is a recurring topic (and rightly so).

lwIP socket API is *not* multi-threaded safe in the *generic* sense, 
i.e. for a full-pre-emptive environment (this is as far as I know).

The practical answer. It depends however on your operating system and 
your implementation of the sysarch.c layer whether your lwIP system
is thread-safe.

> As I’m hunting a race condition in my environment using lwIP + socket API, I
> wonder if the problem my lay in the fact I’ve two threads calling the socket
> API (one for sending using sendto and one for receiving using recvfrom).
>
> I already found out that the sys_sem_wait() function sys.c is sometimes
> re-entered (about once a hour), which it doesn’t seem to be designed for
> (?).
I think you may need to add debug and/or tracing statements and then 
stress test the system trying to reproduce the situation.

Regards,

Leon.