size of bit field

[Nikolay Moskvichev]

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.

 

[Ian Collins]

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.