[lwip-users] sys_mbox_fetch & sys_mbox_fetch_timeout compatible?

[Andrew Lentvorski]

I'm attempting to implement a true 2 thread version of simhost using the 
sockets interface.  To do that, I need to break into the tcpip_thread 
loop and poll the hardware interface and then poll the message queue and 
then loop (currently, simhost uses at least 3 threads).

However, sys_mbox_fetch is blocking with no timeout.  It looks like I 
need sys_mbox_fetch_timeout.

This scares me a bit.

Is sys_mbox_fetch just sys_mbox_fetch_timeout(mbox, msg, 0)?  If so, why 
the compile switch required to change between them?  Why aren't *both* 
functions provided?  Why isn't sys_mbox_fetch implemented in terms of 
sys_mbox_fetch_timeout?

Can I just use sys_mbox_fetch_timeout(mbox, msg, 1) to do what I want? 
What are the downsides to this (other than high CPU and a 1 millisecond 
lag before handling the next packet)?

Thanks,
-a