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Date: Wed, 13 May 2015 22:08:46 +0300
From: "Eli Zaretskii (eliz AT gnu DOT org)" <djgpp AT delorie DOT com>
Subject: Re: bad pragma in dir.h? (and our structrure packing)
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> Date: Wed, 13 May 2015 21:55:53 +0300
> From: "Ozkan Sezer (sezeroz AT gmail DOT com)" <djgpp AT delorie DOT com>
> 
> On 5/13/15, Eli Zaretskii (eliz AT gnu DOT org) <djgpp AT delorie DOT com> wrote:
> >> Date: Wed, 13 May 2015 18:29:39 +0300
> >> From: "Ozkan Sezer (sezeroz AT gmail DOT com)" <djgpp AT delorie DOT com>
> >>
> >> In dir.h, structs ffblk and ffblklfn are surrounded by #pragma pack(1)
> >> and #pragma pack(4), obviously with purpose of having those two structs
> >> at byte packing.  But the restoration of the original packing by that
> >> #pragma pack(4) seems wrong: do we not need a #pragma pack() in there,
> >> or am I missing something?
> >
> > Wasn't that already fixed in the past?
> 
> Well, obviously not. that pragma pack(4) is there in the cvs

People make mistakes when they commit, so it could well be that the
problem was fixed at some point and then broken again in a subsequent
commit.

> > See the DJGPP FAQ (node "Struct size"): it tells that the GNU C++
> > compiler doesn't allow having that attribute on the entire struct.
> > Perhaps that's changed nowadays, I don't know.  (Btw, which compiler
> > versions should be supported by djdev205?  That is, which versions of
> > GCC are supported to compile the library?)
> >
> 
> If you are mentioning http://www.delorie.com/djgpp/v2faq/faq22_12.html

No, that's a different node (compare their names).  I meant
http://www.delorie.com/djgpp/v2faq/faq22_11.html.  It says:

	 struct my_struct {
	   char name[7];
	   unsigned long offset;
	   double quality;
	 } __attribute__ ((packed));

  However, note that the latter will only work when you compile it as a C
  source; C++ doesn't allow such syntax, and you will have to fall back to
  declaring each struct member with the packed attribute.  Therefore, it's best
  to only use declarations such as above if you are *certain* it won't be ever
  compiled as a C++ source.

Once again, a lot has changed in C++ since then, so if all the
versions of GCC we want to support allow the above, there's no reason
to keep the attribute on each member of those structs.

> You looked at the headers I mentioned, yes?

Yes, why do you ask?