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Message-ID: <3FBC1CDA.7090508@treshna.com>
Date: Thu, 20 Nov 2003 14:46:02 +1300
From: Dru <andru AT treshna DOT com>
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To: "Demmer, Thomas" <TDemmer AT krafteurope DOT com>
CC: "'cygwin AT cygwin DOT com'" <cygwin AT cygwin DOT com>,
   "'dru AT treshna DOT com'" <dru AT treshna DOT com>
Subject: Re: problem with sizeof struct alignment
References: <8D861ADC5B8FD211B4100008C71EA7DA04F712D2 AT kjsdemucshrexc1 DOT eu DOT pm DOT com>
In-Reply-To: <8D861ADC5B8FD211B4100008C71EA7DA04F712D2@kjsdemucshrexc1.eu.pm.com>
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Demmer, Thomas wrote:

>Andrew Hill <dru at treshna dot com> wrote
>
>  
>
>>I have this struct
>>
>>
>>typedef struct {
>>double arrival;
>>double departure;
>>char status;
>>int bookingid;
>>int userid;
>>} RoomStatus;
>>
>>
>>I'm using gcc with no compiler options or flags. Under linux with
>>gcc, sizeof(RoomStatus) returns me 28 - as i would expect. If I use a
>>borland C++ compiler it also returns a sizeof 28. But with cygwin +
>>gcc it returns a sizeof 32. I'm a bit confused. Does cgwin + gcc align
>>to nearest 8bytes for structs? Is there a compiler option to tell it
>>to use 4 byte alignment? Is it just me whos having this problem?
>>
>>I checked the sizeof for int, double and char and they all correct,
>>changing the char to an int or specifically saying its a 4bit int
>>doens't seem to make any difference.
>>    
>>
>
>gcc -mno-align-double 
>is your friend to achieve ABI compatibility. This mis-feature
>was introduced with gcc-3.whatever. Search the mailing
>list for a remark from Brian Ford giving a heads up on this problem.
>
>  
>

Thanks I'll try that.  Found the orginal post by Brian.



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