Re: [lwip-users] pbuf len field equal zero

[EVS Hardware Dpt]

Dear all, Christiaan,

To sum it all,

Now I skip the pbuf "with len field being zero" (I should really give it a name, it remind me Harry Potter ;-) ), so it's not a problem anymore. I've tried what Christiaan suggested (using LWIP_DEBUG), but for the moment I haven't found anything. Still searching.

I'm not sure if it's normal to have this behaviour although I can accomodate. I think most of the time people use a memcpy inside a loop  to transfer data to their Ethernet Controller Buffers, and thus having a memcpy wich should transfer 0 bytes is not a problem. So I wonder if people were able to catch this "behaviour" because it shouldn't cause any failure.

Frederic.

2005/12/14, Christiaan Simons <address@hidden>:

lwip-users-bounces+christiaan.simons=address@hidden wrote on 13-12-2005
18:18:39:

> I think you have misunderstood my previous message. I get a pbuf

Oops.

> with len field being 0 from LWIP in my low_level_output function, so
> before sending it to my Controller, not in my receive handler.

Now I undersand it's the outgoing side of things. Hmm...

> Concerning the workaround I have, I simply do not transfer this
> buffer to my Controller.

Ok.

> The question remain : Why does I receive (from lwip) a pbuf chain
> with a pbuf element wich has a len field being 0 ?

Good question. I really don't know what's happening,
maybe you can track it down by using the LWIP_DEBUG macro's.

Christiaan Simons

Hardware / Software Engineer
Axon Digital Design

+31 (0)13 511 66 66
+31 (0)13 511 41 51

http://www.axon.tv


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