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Date: Tue, 04 May 1999 22:24:05 +0200
From: Anders Norlander <anorland AT hem2 DOT passagen DOT se>
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To: Mumit Khan <khan AT xraylith DOT wisc DOT edu>
CC: DJ Delorie <dj AT delorie DOT com>, cygwin-developers AT sourceware DOT cygnus DOT com
Subject: Re: Patch, Version 4: Problem solved
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Mumit Khan wrote:
> 
> On Tue, 4 May 1999, DJ Delorie wrote:
> 
> > The alignment of A changes from 4 bytes (sizeof(int)) to 8 bytes
> > (sizeof(double)), so the alignment of B (which contains A) must also
> > change from 4 to 8.  The size of B is increased to a multiple of the
> > alignment so that each element of an array of such objects is properly
> > aligned.  IMHO, this is correct and expected behavior.
> 
> Exactly.
Yes, I agree to this as well. Although old gcc don't.
 
> > If MS wants them "less aligned" you'll have to use gcc's alignment
> > directives to reduce the alignment of that double to 4.
> 
> MS and GNU do agree on this for a change! The bug is elsewhere since as
> far as I can tell, MS and GNU are doing exactly the same thing (I did try
> out Anders' code posted to egcs-bugs, and get the same result, as expected
> in this particular case, from MSVC 5.0 and EGCS-1.1.2).
> 
> Anders, are you sure the code for the particular structure is in the right
> packing mode (I believe it should pack(4) for LUID_AND_ATTRIBUTES)?
Hmm. I hadn't considered that MS may have used different packings.

> I also checked the code using `#pragma pack(4)', and get the same result
> from both compilers.

The question is should we go for PACKED on particular structures or
should
everything in winnt be pack(4)?

Regards,
Anders