[Boost-users] [Units] Bug with BOOST_UNITS_STATIC_CONSTANT and precompiled headers on MSVC

3 Jan 2009

      I think that I've run across a bug, either in Units, or in MSVC.
Because it only appears when precompiled headers are in use, I suspect
it may be a bug in MSVC.  Basically, if BOOST_UNITS_STATIC_CONSTANT is
used in a header that is compiled into the precomiled header, there will
be linker errors.

Here is my information:
Microsoft Windows XP Professional x64 Edition
Microsoft Development Environment 2003 Version 7.1.6030
Microsoft Visual Studio .NET 2003 Service Pack 1 (KB918007)

Below is the minimial code to reproduce the error.  There are 4 files,
stdafx.h, stdafx.cpp (which is used to create the pch), a.cpp, and
b.cpp.  The same code without precompiled headers turned on links fine.

// start of stdafx.cpp
#include "stdafx.h"
// end of stdafx.cpp

// start of stdafx.h
#ifndef STDAFX_H_328A91DC_3924_466E_80EA_C9BB6CBF7638
#define STDAFX_H_328A91DC_3924_466E_80EA_C9BB6CBF7638

#include 

BOOST_UNITS_STATIC_CONSTANT(ONE_METER, boost::units::si::length);

#endif
// end of stdafx.h

// start of a.cpp
#include "stdafx.h"
int main(void)
{
    boost::units::si::meter;
    return 0;
}
// end of a.cpp

// start of b.cpp
#include "stdafx.h"
int main2(void)
{
    boost::units::si::meter;
    return 0;
}
// end of b.cpp

Here is the error message:
unit.obj : error LNK2005: "class unit >,struct
boost::units::dimensionless_type>,struct
boost::units::homogeneous_system > >,struct boost::units::list > > > > > > > >
...
,void>::boost::unit >,struct
boost::units::dimensionless_type>,struct
boost::units::homogeneous_system > >,struct boost::units::list > > > > > > > > >,void> const & const boost::units::si::`anonymous
namespace'::meter"
(?meter@?A0x490e06d9@si@units@boost@@3ABV?$unit@U?$list@U?$dim@Ulength_base_dimension@units@boost@@V?$static_rational@$00$00@23@@units@boost@@Udimensionless_type@23@@units@boost@@U?$homogeneous_system@U?$list@Umeter_base_unit@si@units@boost@@U?$list@U?$scaled_base_unit@Ugram_base_unit@cgs@units@boost@@U?$scale@$09V?$static_rational@$02$00@units@boost@@@34@@units@boost@@U?$list@Usecond_base_unit@si@units@boost@@U?$list@Uampere_base_unit@si@units@boost@@U?$list@Ukelvin_base_unit@si@units@boost@@U?$list@Umole_base_unit@si@units@boost@@U?$list@Ucandela_base_unit@si@units@boost@@U?$list@Uradian_base_unit@angle@units@boost@@U?$list@Usteradian_base_unit@angle@units@boost@@Udimensionless_type@34@@34@@34@@34@@34@@34@@34@@23@@34@@units@boost@@@23@X@34@B)
already defined in stdafx.obj
unit2.obj : error LNK2005: "class unit >,struct
boost::units::dimensionless_type>,struct
boost::units::homogeneous_system > >,struct boost::units::list > > > > > > > >
,void>::boost::unit >,struct
boost::units::dimensionless_type>,struct
boost::units::homogeneous_system > >,struct boost::units::list > > > > > > > > >,void> const & const
boost::units::si::`anonymous namespace'::meter"
(?meter@?A0x490e06d9@si@units@boost@@3ABV?$unit@U?$list@U?$dim@Ulength_base_dimension@units@boost@@V?$static_rational@$00$00@23@@units@boost@@Udimensionless_type@23@@units@boost@@U?$homogeneous_system@U?$list@Umeter_base_unit@si@units@boost@@U?$list@U?$scaled_base_unit@Ugram_base_unit@cgs@units@boost@@U?$scale@$09V?$static_rational@$02$00@units@boost@@@34@@units@boost@@U?$list@Usecond_base_unit@si@units@boost@@U?$list@Uampere_base_unit@si@units@boost@@U?$list@Ukelvin_base_unit@si@units@boost@@U?$list@Umole_base_unit@si@units@boost@@U?$list@Ucandela_base_unit@si@units@boost@@U?$list@Uradian_base_unit@angle@units@boost@@U?$list@Usteradian_base_unit@angle@units@boost@@Udimensionless_type@34@@34@@34@@34@@34@@34@@34@@23@@34@@units@boost@@@23@X@34@B)
already defined in stdafx.obj
Any insights would be appreciated.

Thanks,
David

[Boost-users] [Units] Bug with BOOST_UNITS_STATIC_CONSTANT and precompiled headers on MSVC

David Walthall