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size of bit field

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  size of bit field Nikolay Moskvichev <nikolay.moskvichev@gmail.com> - 2011-06-29 21:37 -0700
    Re: size of bit field Ian Collins <ian-news@hotmail.com> - 2011-06-30 17:38 +1200

#7262 — size of bit field

Hello All.

size of this bit_field is 2 for gcc or borland, and 4 for msvc 2008
and 2010.
Can you please explain me this behaviour?


#include <iostream>
#pragma pack(push,1)

struct  bit_field {
  unsigned  f1  : 5;
  unsigned  f2  : 4;
  unsigned  f3  : 7;
};

#pragma pack(pop)

int main()
{
   std::cout<<sizeof(bit_field)<<std::endl;
}

Thanks.

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#7263

On 06/30/11 04:37 PM, Nikolay Moskvichev wrote:
> Hello All.
>
> size of this bit_field is 2 for gcc or borland, and 4 for msvc 2008
> and 2010.
> Can you please explain me this behaviour?
>
>
> #include<iostream>
> #pragma pack(push,1)

This is compiler specific, so you would be better off asking on a more 
specialised group.

My *guess* is that the directive is ignored by msvc.

-- 
Ian Collins

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