From: "Tonu Aas" <tonu AT ids DOT ee>
Newsgroups: comp.os.msdos.djgpp
References: <96eb2770 DOT 0206270530 DOT 3d2253dc AT posting DOT google DOT com>
Subject: Re: How to align members/data under gcc/DJGPP?
Date: Thu, 27 Jun 2002 19:06:02 +0300
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

> I can't find in FAQ (sorry, maybe I missed it), how to align struct
> members under gcc/DJGPP? What is pragma/option doing this?

I use header files for that:

struct aligned_struct
 {
  char    a_default;
#include "align4.h"
  char    a_4;
#include "popalign.h"
  char    aa_default;
 }

Works well with several compilers so far... (also gcc)
Its unbelievable that aligning isnt part of C standard, but it is.
Writing protable code in C is hard work. Look for some portabel code: 50% of
text are
#ifdef-s for several compilers, OS-s and platforms stupidities.

---------------------
align1.h:

#ifndef _MSC_VER
#pragma nopackwarning
#endif

#if !(defined(lint) || defined(_lint))
# ifndef RC_INVOKED
#  if(_MSC_VER >= 800) || (defined(__BORLANDC__))
#   pragma warning(disable:4103)
#   if !defined(MIDL_PASS) || defined(__midl)
#    pragma pack(push)
#   endif
#   pragma pack(1)
#  else
#   pragma pack(1)
#  endif
# endif
#endif
-----------------------
align2.h:

#pragma nopackwarning
#if !(defined(lint) || defined(_lint))
# ifndef RC_INVOKED
#  if(_MSC_VER >= 800) || (defined(__BORLANDC__))
#   pragma warning(disable:4103)
#   if !defined(MIDL_PASS) || defined(__midl)
#    pragma pack(push)
#   endif
#   pragma pack(2)
#  else
#   pragma pack(2)
#  endif
# endif // ndef RC_INVOKED
#endif  // !(defined(lint) || defined(_lint))#pragma nopackwarning
--------------

... and so on, and after
-----------------
popalign.h:

#ifndef _MSC_VER
#pragma nopackwarning
#endif

#if !(defined(lint) || defined(_lint))
# if(_MSC_VER >= 800) || defined(__BORLANDC__)
#  pragma warning(disable:4103)
#  if !defined(MIDL_PASS) || defined(__midl)
#   pragma pack(pop)
#  else
#   pragma pack()
#  endif
# else
#  pragma pack()
# endif
#endif