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

On 3/25/2013 9:52 AM, Corinna Vinschen wrote:
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

           ^           ^

It's hard to see, but the error message actually does have double

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

I copied manually from the windows error message, so Yaakov highlighted
that I have missed the double underscores as "hard to see".

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

In any case, the error is a result of adding one of Dave Korn's patches:;a=blob;f=4.7-libstdc-dllimport.patch;hb=refs/heads/4.8#l29

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...


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