From: ranger3 AT m-net DOT arbornet DOT org
Newsgroups: comp.os.msdos.djgpp
Subject: Re: typedef'ing a 24-bit integer
Date: Tue, 01 Jun 1999 03:18:33 GMT
Organization: Deja.com - Share what you know. Learn what you don't.
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References: <37459ABF DOT FF51CA41 AT aaual DOT ualg DOT pt> <374601DE DOT 630CEA74 AT cartsys DOT com> <3746C21F DOT 201AF26D AT user DOT rose DOT com>
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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

In article <3746C21F DOT 201AF26D AT user DOT rose DOT com>,
  djgpp AT delorie DOT com wrote:
> Nate Eldredge wrote:
>
> > Miguel Guerreiro wrote:
> > >
> > > How can you do somethin kinda like this:
> > >
> > >             typedef int24 (24-bit integer)
> > >             typedef uint24 (24-bit unsigned int)
> > >
> > > I want it to take *exactly* 24-bit of space
> >
> > You can't.
>
> Couldn't he create a struct with a 24-bit bit field?  It would still
> take 32 bits of space but would manipulate as 24 bits (I think).


You can do something like :

typedef struct s {
  unsigned int : 24
} __attribute__((packed)) uint24 ;

under gcc
and #pragma(1) under msoft c++ to get a packed 24 bit structure.

The signed follows from above.



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