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Re: 64bit: cygstdc++-6.dll

On Mar 24 03:33, Yaakov (Cygwin/X) wrote:
> On 2013-03-23 04:50, Corinna Vinschen wrote:
> >On Mar 22 19:11, marco atzeri wrote:
> >>latest libstdc++6-4.8-20130319-1
> >>
> >>has at least a missing entry point from previous dll
> >>
> >>cmake fails with
> >>"_ZTVN10_cxxabiv117_class_type_infoE could not be located"
> >
> >However, a quick glance into the symbols exported by libstdc++.a
> >shows that the above symbol exists, but with additional leading
> >underscores:
> >
> >   _ZTVN10__cxxabiv117__class_type_infoE
> >           ^           ^
> It's hard to see, but the error message actually does have double
> underscores.

I don't quite understand.  From what Marco pasted above, it doesn't.

> >The x86_64 ABI does not prepends underscores in front of symbols,
> >so there has evidently gone something wrong.  I checked my the Linux
> >cross toolchain and it is also using the symbols with additional
> >leading underscores.  Off the top of my head I don't see where this
> >discrepancy is caused.
> The PE underscore only applies to the very beginning of a symbol,
> not to every component of a C++ symbol name.  Those double
> underscores are straight from libstdc++ code, as they are internal
> symbols.
> In any case, the error is a result of adding one of Dave Korn's patches:
> I have omitted that patch in the new 4.8.0-1.  Hopefully Dave can
> explain the purpose and necessity of that patch, since it would seem
> that using (at least that hunk of) it would require rebuilding most
> C++ packages in 64bit/release; if it's really necessary, then we
> will want to do that sooner rather than later.

That I don't quite understand either.  If this is only about missing
exported symbols and not about the name, how are the already built
C++ packages affected?  They could be built, so they didn't use this
symbols, apparently.

I'm slightly confused now...


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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