Re: static vs. shared linking

[David Stacey <drstacey at tiscali dot co dot uk>]

On 25/03/2015 09:04, Corinna Vinschen wrote:
> On Mar 24 18:39, David Stacey wrote:
> > On 24/03/2015 00:02, David Stacey wrote:
> > > I've been having difficulty building poco-1.6.0 for Cygwin for some
> > > time. I've managed to produce a test case that shows the problem:
> > >
> > > https://dl.dropboxusercontent.com/u/119453582/Cygwin/crashtest.tar.xz
> > >
> > > This archive contains source files that produce a very simple library.
> > > When linked statically, the code works fine. However, when linked as a
> > > shared DLL, the test crashes with a core dump. The behaviour is
> > > identical on x86 and x86_64 architectures.
> > >
> > > Have I made a stupid error in the compilation of the shared case, or is
> > > something more interesting going on?
> >   
> > I don't know if anyone has managed to look at this. I haven't had a deluge
> > of e-mails telling me that I've done something silly (which is a shame,
> > because then I could fix it quickly and move on). For the sake of a straw to
> > clutch at, I tried compiling with clang++ rather than g++, and got the same
> > result:
> >   
> >        $ ./go.sh
> >        Running test (static link)...
> >        Done.
> >   
> >        Running test (shared link)...
> >        ./go.sh: line 19:  3744 Aborted                 (core dumped)
> > ./shared_test
> >        Done.
> >   
> > Any help or hints would be greatly appreciated.
> For a start, you should contemplate to build your test with -g to allow
> debugging.  Then you can run the testcase under GDB and get (more or less)
> useful output.  The crash occurs in a delete call, afaics.  If you
> install the cygwin-debuginfo package, addr2line returns something like this
> as the call stack (non-required path components removed):
>
> [...]/cygwin/exceptions.cc:1247
> [...]/cygwin/exceptions.cc:1501
> [...]/cygwin/sigproc.cc:717
> [...]/cygwin/signal.cc:252
> [...]/cygwin/signal.cc:303
> [...]/cygwin/signal.cc:313
> [...]/cygwin/signal.cc:289
> [...]/cygwin/signal.cc:375

Thank you for your comments - they were really helpful. Yes, I should 
have specified '-g' on the command line - that was an omission on my 
part - sorry.

I've never had much joy out of addr2line before, and I'm struggling to 
recreate what you've done. I've added '-g' to the command line, run 
'go.sh' again. This generates a fresh stackdump file, and then I do:

awk '/^[0-9]/{print $2}' shared_test.exe.stackdump | addr2line -f -e 
shared_test.exe

but I just see question marks. Please could you show the exact lines 
you're using.

Many thanks,

Dave.



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