[Boost-build] [cygwin][bbv2][python] linking DLLs to one another

From: David Abrahams (dave_at_[hidden])
Date: 2007-03-09 00:45:19

As Boost moves to v2 of its build system, we have removed the
capability to tell gcc to generate import libraries, instead
attempting to use the same dynamic linking paradigms used by GCC on
linux.  Why use different logic on Cygwin, after all?

This has caused problems for Boost.Python, which has to be able to
generate dynamically-loaded Python extension modules that link to the
Boost.Python shared library, libboost_python.dll.  As far as I can
tell, Cygwin's simulation of the linux ability to link without implibs
is not entirely transparent, since any inline function used by both
libboost_python.dll and the Python extension modules will cause a
multiple-definition error at link time.  

Can some Cygwin person confirm that this is the behavior you'd expect
when linking two DLLs together, each of which contains an
instantiation of a particular inline function?  Can you offer a
workaround that doesn't involve import libraries (I'm willing to
generate one; I just want to know)?

For the Boost.Build people, IMO even if there's a workaround, the
ability to generate implibs has to be restored before we ship, as it's
a crucial function of BBv1 (and some people are surely using it in the
mingw configuration of gcc, if not the cygwin one).

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