[U-Boot] IP_t should be a "packed" struct

Wolfgang Denk wd at denx.de
Wed Jan 28 23:27:47 CET 2009


Dear Luigi Mantellini,

In message <b73e93990901281416k766b2bf3qc6429f77545f9191 at mail.gmail.com> you wrote:
> 
> I think that an audit of the code is important to understand if we
> have a problem (or not) and how large is the problem.

We (i. e. all of us except you) do not have a problem.

> My compiler is not broken...

Well, YMMV...

> cassini linux # find -name \*.c -o -name \*.h |xargs grep attribute |
> grep packed | wc -l
> 3153
> 
> I see a lot of packed structs...



> > Here is for example a copy of /usr/include/netinet/ip.h :
...
> This doesn't say anything regarding how kernel guys have resolved the
> problem (if they are solved...). Checking the kernel headers a lot

This is not a kernel header. This is one of the standard user space
network headers, and a pretty central one. Feel free to check any
others.

> I think that "struct packing" needs to be understood and a global

I agree on this. This definitely needs to be understood.

Hm... I think I understand it, and it works for me :-)

> mechanism should be used (like -fpack-struct option always defined or
> a style guideline that requires a tag for each structs). From my point

I think this is not needed. Please read the docuemntation about
alignment and padding. It is pretty clear.

Best regards,

Wolfgang Denk

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