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This is the mail archive of thebinutils@sources.redhat.commailing list for thebinutils project.
Re: Does a zero-sized object in BSS go away?
> Date: Fri, 27 Jun 2003 11:10:31 +0200> From: Thiemo Seufer <ica2_ts@csv.ica.uni-stuttgart.de>> Geoff Keating wrote:> > > Date: Thu, 19 Jun 2003 14:19:39 -0400 (EDT)> > > Cc: binutils@sources.redhat.com> > > From: Kazu Hirata <kazu@cs.umass.edu>> > > > > Hi Geoff,> > > > > > > The linker should assign an address to it. However, some object file> > > > formats can't represent zero-sized common objects, in which case the> > > > assembler should probably report an error if someone tries to create one.> > > > > > Thanks. That means some valid C using a zerosized object program> > > may not be represented in those formats. Sigh...> > > > ISO C programs can't create zero-size objects, but you can do it in> > GCC.> > > > I think there's no way to tell if an object, which the program thinks> > is zero-size, actually has non-zero size. So you could just make the> > common symbols have size 1 if the user asks for size 0...> > This may break pointer comparisions. (Not that I knew of a good reason> to do this).I don't see how this could break pointer comparisons. You can'tmeaningfully do them with zero-size objects anyway...-- - Geoffrey Keating <geoffk@geoffk.org>
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