[Boost-build] building boost on interix

Subject: [Boost-build] building boost on interix
From: Robert Oeffner (robert_at_[hidden])
Date: 2009-07-22 10:58:05

Hi,
I'm trying to build Boost1.39.0 on interix which is a UNIX subsystem running on top of the NT kernel for Windows. MS provides interix as an optional add-on.
The particular software I'm trying to compile is the Crystallographic Toolbox, CCTBX, and although it compiles it is with several warnings virtually all of the form:

boost/python/detail/signature.hpp:77: warning: sorry: semantics of inline function static data 'const boost::python::detail::signature_element result [10]' are wrong (you'll wind up with multiple copies)

A problem with GCC on interix is that binutils do not support weak symbols. From what I've read I believe that the above warning is due to the compilers lack of support for weak symbols. A small test example on 
http://www.mail-archive.com/[e-mail]/msg46130.html 
illustrates the problem. Indeed when I compile this piece of code on interix I get:

~/tmp/weakboost>
~/tmp/weakboost> g++ -I/E/Users/oeffner/Interix/Boost/boost_1_39_0 weak1.cpp
In file included from weak1.cpp:2:
/E/Users/oeffner/Interix/Boost/boost_1_39_0/boost/crc.hpp: In static member function 'static void boost::detail::crc_table_t<Bits, TruncPoly, Reflect>::init_table() [with unsigned int Bits = 32u, typename boost::uint_t<Bits>::fast TruncPoly = 79764919u, bool Reflect = true]':
/E/Users/oeffner/Interix/Boost/boost_1_39_0/boost/crc.hpp:838:   instantiated from 'boost::crc_optimal<Bits, TruncPoly, InitRem, FinalXor, ReflectIn, ReflectRem>::crc_optimal(typename boost::detail::mask_uint_t<Bits>::fast) [with unsigned int Bits = 32u, typename boost::uint_t<Bits>::fast TruncPoly = 79764919u, typename boost::uint_t<Bits>::fast InitRem = -1u, typename boost::uint_t<Bits>::fast FinalXor = -1u, bool ReflectIn = true, bool ReflectRem = true]'
weak1.cpp:6:   instantiated from here
/E/Users/oeffner/Interix/Boost/boost_1_39_0/boost/crc.hpp:492: warning: sorry: semantics of inline function static data 'bool did_init' are wrong (you'll wind up with multiple copies)
/E/Users/oeffner/Interix/Boost/boost_1_39_0/boost/crc.hpp:492: warning:   you can work around this by removing the initializer
/tmp/ccCxFr4u.o(.text+0xf0):weak1.cpp: undefined reference to `boost::detail::crc_table_t<32u, 79764919u, true>::table_'
collect2: ld returned 1 exit status
~/tmp/weakboost>

The compiled binaries from the CCTBX also have problems. It is at present not possible to load boost-python modules from CCTBX in python on interix as it produces a core dump. I think that the lack of support for weak symbols used by the boost library templates  is what causes this.
However, Boost compiles well on platforms without weak symbol support, such as win32 (the cited example compiles fine with VC2005 as does the CCTBX). I would like to know what flags I can tweak a compilation of Boost with on interix to specify that I do not want GCC attempting to use weak symbols. If anyone has got any suggestions that would be great.

Many thanks,

Robert