one pragma pack vs. many, many __attribute__((packed))

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1.Why #pragma pack() not take effect?

Struct definition as following(on 32-bit Linux):

#pragma pack(push, 8)
struct MY_STRUCT
{
    char a[2];
    short b;
    short c;
    short d;
    int e;
    long long x;
    long long y;
};
#pragma(pop)

During the test, result of 'sizeof(struct MY_STRUCT)' is 28. Why not 32?
As I had expected, a,b,c,d will be packed into one 8-byte, e one and x, y
two. Ain't I right?

If I get wrong usage of #pragma pack(), could anyone please tell me how to
get it work correctly?

BTW, what on earth is the difference between __attribute__ align() and
#pragma pack()?

Thanks in advance!

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4.sigbux with __attribute__((packed)) on irix

Hi,

I'm using IRIX 6.5 and gcc 2.95.2 (and I'd prefer not to upgrade ;-) ).
I have to use packed structs in my program (yes, I know I shouldn't.
But I have to). But the following program gives a SIGBUS:

#include <iostream>
using namespace std;

typedef struct Test
{
    short a;
    unsigned int b;
} __attribute__((packed)) Test;


void myBla(unsigned int* i)
{
    *i = ((*i)>>24) | (((*i)>>8) & 0xff00) | (((*i)<<8) & 0xff0000) |
((*i)<<24);
}
int main()
{
    Test t = { 0x0100, 0x01000000 } ;
    myBla(&t.b); //<- BANG

    cout << sizeof(t) << " " << t.b << endl;
    cout << sizeof(short) << " " << sizeof(unsigned int) << endl;
}


Why is this? (And if the all to myBla() is uncommented, the output is
6 256
2 4
, and the 256 isn't right either).

TIA,
Nico

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