[lwip-users] 1.4.0.rc1: How to use netconn-API for non-blocking connect?

[Benjamin Schelte]

Dear all,

 

I am currently integrating the first release candidate of lwIP 1.4.0 into my project, because I need non-blocking connect support.

As I could not find any example sources or documentation about this feature I tried it on my own, but so far I could not succeed.

 

My setup is the following:

lwIP v1.4.0.rc1

RTOS

Netconn-API

 

The sequence I use to connect to another device in non-blocking mode is basically the same as previously with one difference:

 

…

psNetconn = netconn_new(NETCONN_TCP);    // New tcp connection

netconn_set_nonblocking(psNetconn, TRUE);      // Don't block!

if (psNetconn != NULL) {

      eError = netconn_connect(psNetconn, &sPeerIPAddress, (u16_t)usPort);

      if (eError == ERR_OK) {

            // Connection established, create request

            …

}

else {

// Connection error, Reset connection and task status

…

}

else {

// Connection error, Reset connection and task status

…

}

…

 

// Close and delete the connection

if (psNetconn != NULL) {

      netconn_close(psNetconn);

      netconn_delete(psNetconn);

      psNetconn = NULL;

}

…

 

So the only addition in my code is the line below netconn_new: netconn_set_nonblocking().

 

However the call to the function “netconn_connect” always returns ERR_INPROGRESS, but after that nothing more happens.

Neither delaying the task and processing later, nor directly calling “netconn_write” worked (it also returned ERR_INPROGRESS).

 

Could anyone of the developers please give me some advice in how to use the non-blocking connect feature, or how it is supposed to work?

I don’t even know, if the mechanism I use is intended to be solution for the non-blocking connect though.

Thanks in advance.

 

Best regards,

Benjamin