Re: Cygwin GCC linking Python extensions issue

From: David Abrahams (dave_at_[hidden])
Date: 2003-05-23 12:42:47

"Norman Vine" <nhv_at_[hidden]> writes:

>> -----Original Message-----
>> From: cygwin-owner_at_[hidden] [mailto:cygwin-owner_at_[hidden]]On Behalf
>> Of David Abrahams
>> Sent: Friday, May 23, 2003 9:48 AM
>> To: nhv_at_[hidden]
>> Cc: cygwin_at_[hidden]
>> Subject: Re: Cygwin GCC linking Python extensions issue
>>
>>
>> "Norman Vine" <nhv_at_[hidden]> writes:
>>
>> > David Abrahams writes:
>> >>
>> >> Recently I've begun to see the following link errors when building
>> >> some of the Boost.Python test suite extension modules using Cygwin gcc
>> >> (version 2 or 3, doesn't matter) and Python 2.2.2 release or Python
>> >> 2.3 debug. This error happens only on some of the extension modules,
>> >> but all of them use the symbol boost::python::scope::current_scope
>> >> which is defined in libboost_python.dll. Regardless, even if that's
>> >> somehow my bug, there's the matter of `__head_boost_python_dll'...
>> >>
>> >> Does anyone have an explanation/workaround for this?
>> >>
>> >>
>> >> d000000.o(.idata$2+0x0): multiple definition of
>> >
>> >
>> > Tell the linker multiple definitions are allowed by adding
>> > '-Wl,--allow-multiple-definition' to your $LD_FLAGS
>>
>> That's an interesting idea. Still, I'd like to get to the bottom of
>> this. Why would it think there are multiple definitions for these
>> symbol? AFAICT, there are not.
>
> Hmm....
> Looks like both of these lines are being passed to the linker in your
> original message
>
> "c:\build\libs\python\build\bin\boost_python.dll\gcc\debug-python\runtime-li
> nk-dynamic\boost_python.lib"
> "c:\build\libs\python\build\bin\boost_python.dll\gcc\debug-python\runtime-li
> nk-dynamic\boost_python.lib"

Strange; that's never upset the linker in the past. That is just what
my build system does in case there are inter-library (or circular!)
dependencies. It's certainly fine on linux and has always worked
under Cygwin until recently.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com