RE: [lwip-devel] [bug #27034] Invalid ASSERT in pbuf_alloc()

[Bill Auerbach]

>However, I'd like to know what the purpose of
>
>  pbuf_alloc(PBUF_RAW, 0, PBUF_POOL);
>
>is? Since there is no API that supports increasing a pbuf's length
>without
>moving the payload to the front (which you can't in this case, because
>PBUF_RAW is used), you'll end up with a pbuf of zero length, which is
>bound to
>lead to problems in other parts of the stack. There are checks for pbuf-
>>len
>not being zero somewhere... (although I don't remember where and why).

The above is used in PPP, and I use:

pbuf_alloc( PBUF_RAW, 0, PBUF_REF )

in my application.  It's useful for zero-copy output operations.

Bill