[lwip-users] lwip_select() problem

[Chu, Zhenwei]

Hi,

 

LwIP_select() seems do not work properly in my application. My application has 2 UDP ports waiting for multicast packages. Before add select(), I have confirmed that recvfrom() works fine. Here are piece of my code:

 

While(1)

{

            if(select())

{

                        recvfrom();

}

}

 

Select() always return 0; Step into lwIP code, sock->lastdata and sock-> rcvevent are always NULL in lwip_select().

 

However if comment out select() and call recvfrom() directly, sock->lastdata and sock-> rcvevent are NULL too at the beginning in lwip_recvfrom(). Then it calls sock->lastdata = buf = netconn_recv(sock->conn) that trigger udp packages flow in through udp_input().

 

Is this problem caused by mis-configurations in opt.h? What else may cause this problem?

 

Thanks

 

Zhenwei