From: j DOT aldrich6 AT genie DOT com
Message-Id: <199604160421.AA017318484@relay1.geis.com>
Date: Tue, 16 Apr 96 04:10:00 UTC 0000
To: djgpp AT delorie DOT com
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Subject: Re: problem with packed struct

Reply to message 2225083    from ELIZ AT IS DOT ELTA. on 04/15/96  2:46AM


>You should declare ALL the fields with the attribute, like this:
>
>	struct foo
>	{
>	  char a __attribute__((packed));
>	  int x[2] __attribute__((packed));
>	};

There's an easier way to do that:

	struct foo
	{
	  char a;
	  int x[2];
	} __attribute__((packed));

Just put the __attribute__ at the end of the struct definition, and all
its fields are packed automatically.

I had to do something like this for a program that would be
compiled on both DJGPP and Turbo C.  I made all my ints short,
and closed the struct definition with:

#if defined(GNUC)
} __attribute__((packed));
#else
};
#endif

Thus, the resulting structures could be stored by fread() in a format
compatible between both 32-bit and 16-bit compilers, and my data
files wouldn't have to be rewritten every time I switched.

John