Re: [lwip-users] exception in the second call to netconn_bind

[address@hidden]

David Shmelzer wrote:
> I converted all my code to netconn api and it works, but is a bit
> slower.
>
> If I wanted to convert it all to the raw API how do I send to the raw
> API from a separate task? 
> Can I safely call tcp_write from a separate task?
>   

Absolutely not!

> I noticed there's work being done on "locking" the core code to make it
> thread safe. Is this safe to use yet?
>   

That's another issue! To keep it simple, the core is not (and never will 
be) protected agains concurrent access (apart from the memory allocation 
functions). The locking you read about is just the method how higher 
layer APIs use the core. Until now, the core is handled from one single 
thread only (aka the tcpip_thread, because of the loop-function's name) 
and application threads using the socket/netconn API communicate with it 
through message boxes. Although Frédéric started another approach by 
taking a big lock when using the core functions, this is not really 
supported yet *and it will never be* for the raw API, I guess.

What you can do to use the raw API from another thread is to get 
tcpip_callback call a function (with void argument) in the core thread's 
thread-context. This is the same mechanism the other APIs use the core. 
However, you cannot mix the socket/netconn/raw APIs, and you should be 
aware that raw API callbacks are always called from the tcpip_thread.

Simon