RE: [lwip-users] low_level_output question

[John Kennedy]

Ah, that's unfortunate since using the reference count as I described is so 
intuitive and eliminates the need to copy the pbuf in the driver (if it can't 
be sent immediately).  It makes one wonder why UDP sockets use the reference 
count differently, seems like a mistake?

John


 
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John Kennedy


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-----Original Message-----
From: address@hidden [mailto:address@hidden
Sent: Tuesday, April 07, 2009 9:26 AM
To: Mailing list for lwIP users
Subject: Re: [lwip-users] low_level_output question


John Kennedy wrote:
> Since pbuf_free decrements the pbuf reference count and only frees the pbuf 
> when the reference count goes to zero I assumed that by incrementing the 
> reference count in the Ethernet driver it would prevent the stack from 
> freeing or reusing the pbuf, and that the Ethernet driver should then call 
> pbuf_free when done with the pbuf.  My original question was to verify this 
> assumption.
>

Your assumtption is indeed correct, but it doesn't account for
application buffers used with PBUF_REF/_ROM.

Simon


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