Re: [lwip-users] Writing a proxy server - how "non-reentrant" is lwip raw API?

[wurzel]

Leon Woestenberg wrote:
> On Wed, Jun 15, 2011 at 2:13 AM, wurzel <address@hidden> wrote:
>>
>> My question is, can I call tcp_write from within a tcp_recv
>> callback?  In this code, I've opened a pair of TCP pcbs and
>> each one's state struct has a "mate" field that points to
>> the other side's state struct to I can get its pcb.
>>
> I think that's a very good question indeed, because we give no
> explicit guarantee in our documentation that this is guaranteed to
> work, AFAIK. A function is called reentrant if it can be interrupted
> and called again before previous calls complete execution. Now, as
> there are global variables in the stack, we cannot easily guarantee
> reentrancy, other than through code validation.

Thanks for the clear answer; that helps a lot.  I don't have interrupts,
but I was worried about the case "A subroutine that is directly or 
indirectly recursive should be reentrant"  not knowing which routines 
might be shared between those paths.
    http://en.wikipedia.org/wiki/Reentrant_(computing)

I will now go hunt elsewhere for the cause of my sporadic behavior.  :-)

                                                        -wurzel