[lwip-users] TCP client waiting for answer from server

[Walter Saegesser]

Concerns lwIP v1.3.2.

I have a TCP client in an embedded app and after I send the data I have to wait for an answer.

      ….

         netconn_write ( conn, data, size, NETCONN_NOCOPY );

         TNetBuf xBuf = netconn_recv ( conn );

         if ( xBuf != NULL )

         {

            netbuf_copy   ( xBuf, mRcvBuf, csBufSize );

            netbuf_delete ( xBuf );

         }  

This works so far. But what if the server does not answer? The ‘netconn_recv’ does not seem to have a time-out and the application hangs at this point. I see there is a compiler switch ‘LWIP_SO_RCVTIMEO’, which is disabled by default. Is this the means to accomplish a time-out – and what would be the time – or are there other schemes?

 

There is a problem, though. Besides the TCP client there is also a TCP server that actually should block at  ‘netconn_recv’. Hence I have contradicting requirements. How to overcome this?

 

Thanks in advance.

 

Walter

 

 

_______________________________________________
Walter Saegesser
Dipl.-Ing. (FH)

R&D - Software
Business Unit IMS – Line of Business Solar Inverter
_______________________________________________
Delta Renewable Energy Systems (Switzerland) AG
Burgerfeldstrasse 19, CH-8730 Uznach SG, Switzerland
TEL:       +41 (0)55 246-4140
FAX:      +41 (0)55 246-4116
address@hidden
www.deltaenergysystems.com
_______________________________________________

 

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