[lwip-users] Nonblocking sockets problem

[Åke Forslund]

Hello,

 

we’ve run into a bit of a problem when we switched from blocking sockets to non-blocking sockets. From what we can tell when lwip_recvfrom() is executed it always return EWOULDBLOCK  because sock->rcvevent is never incremented and thus

 

if (((flags & MSG_DONTWAIT) || netconn_is_nonblocking(sock->conn)) &&

          (sock->rcvevent <= 0))

 

is always true. We added some debug-prints in the case NETCONN_EVT_RCVPLUS in event_callback() showing that  rcvevent was only incremented when the socket was set as blocking.

 

I’m having trouble seeing where to probe for the error so if anyone has an idea of where to look, I would be very thankful. Is there any options in lwipopt that could trigger this behavior?

From where is event_callback() triggered normally, it’s added as a callback to the netconnection-object but where is this callback called?

We’re running Lwip 1.40.

 

Best regards

/Åke Forslund

 

 

Åke Forslund

Embedded software engineer

Product Development

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