Message-Id: <199609302355.QAA05114@bluesky.com>
Comments: Authenticated sender is <kbaca AT bluesky DOT skygames DOT com>
From: "Kevin Baca" <kbaca AT skygames DOT com>
To: djgpp AT delorie DOT com
Date: Mon, 30 Sep 1996 16:58:43 +0000
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Subject: Re: packed data structures?

> > At first I didn't know why my VBE2 code wasn't working, but then I
> > realized that djgpp wasn't packing the data structures - so I browsed
> > the info files and found "__attribute__((packed))", which seemed to be
> > the answer I was looking for.  I applied this attribute to every field
> > in all of my VBE2 data structures, but the problem still seemed to
> > remain - 16 bit fields were being padded!  Is there a known problem
> > with packing, or is there something I'm overlooking?
> 
> Are you sure you have defined the structures correctly? I do this
> exactly as you have stated, and have no problem at all with it. How
> are you defining your 16 bit fields? You should be using short int's...
> :) 
>  

There are bugs with GCC packing.  For example, under GCC 2.7.2 the 
__attribute__((packed)) directive doesn't work in C++ code.

Try this instead:

#pragma pack(1)

typedef struct
{
   short foo;
   short bar;

} foobar;

#pragma pack()

This seems to work in both C and C++.

-Kevin