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Date: Mon, 17 Mar 2003 13:21:06 +1100 (EST)
From: =?iso-8859-1?q?Danny=20Smith?= <danny_r_smith_2001 AT yahoo DOT co DOT nz>
Subject: Re: cygwin gcc 3.4 and cygwin
To: Brian Ford <ford AT vss DOT fsi DOT com>, cygwin AT cygwin DOT com
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 --- Danny Smith <danny_r_smith_2001 AT yahoo DOT co DOT nz> wrote: > Brian Ford wrote:
> 
> > Vanilla gcc 3.2.x is NOT ABI compatible with Cygwin's pre 3.2 gcc, fact.
> > I wanted to know why this was allowed to persist given the simple patch
> > required to fix it, question.  I had seen Mr. Faylor make statements
> > before to the effect of: doubles in structures are not that common so who
> > cares, so I advised caution in his use of that compiler for official
> > Cygwin released software.
> 
> Regarding the structure alignment problem:
> 
> Adding -malign-double to compile switches should provide
> forward/backward/MSVC
> compatibility.
> 
> The other fix is to rebuild gcc from  sources so that -malign-double is the
> default (as it is now on trunk for cygwin).
> 
> Mr. Danny
> 
> 

To clarify:

Before gcc 3.x, struct alignemnt was not controlled by MASK_ALIGN_DOUBLE, but
by another define (BIGGEST_FIELD_ALIGNMENT) which made 64 bit alignment default
for MSVC compat.

That changed on ???.

MASK_ALIGN_DOUBLE was made default on cygwin branch on 2002-07-05

It is _not_ default on 3.2.x FSF branches.

MASK_ALIGN_DOUBLE was made default for cygwin on FSF 3.3 branch and trunk (3.4)
on 2003-02-16.

If someone cares to submit patch for gcc 3.2.3 branch, feel free.  

Danny

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