fixed memory bytes

[John Mahoney]

On Tue, Jan 4, 2011 at 1:07 PM, Rajesh S R <srrajesh1989 at gmail.com> wrote:
>
>
> On Tue, Jan 4, 2011 at 11:28 PM, Mulyadi Santosa <mulyadi.santosa at gmail.com>
> wrote:
>>
>> On Wed, Jan 5, 2011 at 00:40, mohit verma <mohit89mlnc at gmail.com> wrote:
>> >
>> > hi all,
>> > i have seen many places in  kernel where the variables specially the
>> > structures should be of  fixed size independent of the architecture. i
>> > went
>> > through the  definitions of them  but dint  get  clearly (or frankly
>> > say
>> > ...dint get them even a bit) .
>>
>> Your question isn't specific enough, so I'll just guess. Let's say
>> "int". In 32 bit, AFAIK it's  4 byte, but in 64 bit (like IA 64, not
>> sure if it's x64) it's 8 byte. So, if you just say "int", you will
>> likely getting screwed up.
>>
>> By using types like u_int or something like that, you pretty much say
>> "I mean 4 byte kind of integer" etc
>
>
> Still there can be padding issues due to byte alignment, which may vary
> across architecture. Am not sure if that is controllable (probably some
> pragma to gcc?). Probably, OP is asking about it?

I believe you are referring to __attribute__( ( packed ) )