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[Fwd: Re: [MinGW-dvlpr] [Fwd: Re: [LONG MAIL]: The story of the tiny TAPE_GET_MEDIA_PARAMETERS searching the man in the moon]]


--- Earnie Boyd <earnie_boyd@yahoo.com> wrote: > Ok, Danny, here's the
whole story.
> 
> -------- Original Message --------
> Subject: Re: [LONG MAIL]: The story of the tiny
> TAPE_GET_MEDIA_PARAMETERS searching the man in the moon
> Date: Mon, 18 Jun 2001 00:50:47 +0200
> From: Corinna Vinschen <vinschen@redhat.com>
> Reply-To: cygdev <cygwin-developers@cygwin.com>
> To: cygwin-developers@cygwin.com
> References: <20010615123907.C324@cygbert.vinschen.de>
> <20010615110027.B15095@redhat.com>
> <20010615171439.M324@cygbert.vinschen.de>
> <20010615111627.D15179@redhat.com>
> <20010615181008.N324@cygbert.vinschen.de>
> <20010615121316.A15646@redhat.com> <3B2A7E1F.1CE1D3D0@yahoo.com>
> <20010615204318.D31488@redhat.com> <3B2AB5EE.D6855F4A@yahoo.com>
> <20010615220227.A509@redhat.com>
> 
> On Fri, Jun 15, 2001 at 10:02:27PM -0400, Christopher Faylor wrote:
> > On Fri, Jun 15, 2001 at 09:27:10PM -0400, Earnie Boyd wrote:
> > >Christopher Faylor wrote:
> > >> The problem is apparently that the native gcc compiler and a
> cross
> > >> compiler seem to disagree on default structure packing.
> > >
> > >Perhaps the -fnative-struct patch should be interesting to help?
> > 
> > Perhaps, but the reason I forwarded it here is because I'm swamped
> and
> > don't have time for much investigation in strange (gcc) code.
> > 
> > The theory is that someone in this cooperative project might be
> interested
> > in helping out.
> > 
> > I'd hoped that Corinna would provide more details.  She should be
> back online
> > on Monday.  Maybe we'll hear from her then.
> 
> I only can repeat the mail I originally sent to Chris. I actually
> tried
> to debug gcc on Friday but I don't know too much about gcc and I
> didn't
> find anything obvious in an hour or so. Nevertheless, I was a
> somewhat
> busy with my travel preparations on Friday.
> 
> Ok, the original mail I sent to Chris so everyone can see at least
> the
> result of the problem:
> 
> ============= SNIP =============
> 
> As I already mentioned I'm using the tier1-00r1p2 for cross
> compiling.
> And since that problem already exists in 1.3.2, I suspect that your
> compiler which you're using for building Cygwin has the same problem.
> 
> At least the current native gcc-2.95.3 doesn't have it. Otherwise
> mt would have used the same wrong value of 28.
> 
> The difference is only explainable by the pack algorithm. The
> cross compiler uses a default structure packing of 4 Bytes and
> the native gcc a default packing of 8 Bytes, probably.
> ============= SNAP =============
> 
> Just a guess: Perhaps, the cross compiler uses the packing
> algorithm of the HOST instead of the TARGET.
> 
> Corinna
> 
Another "Just a guess":
If cross-compiler was built before's Mumit's changes to implemtation of
#pragma(pack,[1248], then it may be misinterpreting some of the packing
pragmas in current w32api.  I am referring to these changes:

+ Fri Jul  2 22:13:14 1999  Mumit Khan  <khan@xraylith.wisc.edu>
+ 
+ 	* c-pragma.h (PRAGMA_INSERT_ATTRIBUTES): Delete macro.
+ 	(insert_pack_attributes): Delete prototype.
+ 	(enum pragma_state): Simplify.
+ 
+ 	* c-pragma.c (struct align_stack): Lose num_pushes field.
+ 	(push_alignment): Remove redundant check for valid alignment;
+ 	always push on stack.
+ 	(pop_alignment): Update prototype. Implement combination rule.
+ 	(insert_pack_attributes): Lose.
+ 	(handle_pragma_token): Document syntax. Simplify pack(push/pop)
+ 	attributes and implement documented syntax.
+ 
+ Sun Jul  4 13:18:23 1999  Mumit Khan  <khan@xraylith.wisc.edu>
+ 
+ 	* i386/cygwin.h (PCC_BITFIELD_TYPE_MATTERS): Fix typo and 
+ 	define to be 1.
+ 	(GROUP_BITFIELDS_BY_ALIGN): Define.
+ 

IIRC, many of the packing pragmas were introduced into w32api headers
in a Nov,1999 snapshot.

Danny

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