Re: [lwip-users] tcp_write problem after the first transmission

[Bernhard 'Gustl' Bauer]

Hi,

I think it is the loop. The code that handles the ACK is not executed 
before the loop ends. How is this code called?

HTH

Gustl

Daniel Berenguer schrieb:
> I'm trying to send a bunch of TCP packets using the raw API but
> tcp_write is returning -1 (out of memory) after the 8th packet.
>
> for (i=0 ; i<20 ; i++)
> {
>     strcpy(buffer, "holaaa");
>     res = tcp_write(pcb, buffer, 7, 0);
>     tcp_output(pcb);
> }
>
> I've used many variants of the above code (with delays, w/o
> tcp_output, ...) but the problem is always there. The first packet is
> sent immediately after the first tcp_write but then, tcp_write just
> pushes the packets into the sending queue. TCP_SND_QUEUELEN is set to
> 8 so once the TX queue gets overflowed tcp_write starts returning -1
> and the contents of the queue is finally sent (only 7 packets of 20
> though).