Re: [Boost-bugs] [Boost C++ Libraries] #1097: keyword.hpp generates many warnings C4180: qualifier applied to function type has no meaning; ignored

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #1097: keyword.hpp generates many warnings C4180: qualifier applied to function type has no meaning; ignored
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2007-10-17 17:05:50

#1097: keyword.hpp generates many warnings C4180: qualifier applied to function
type has no meaning; ignored
-------------------------------+--------------------------------------------
  Reporter:  pbristow          |       Owner:  danielw                
      Type:  Bugs              |      Status:  new                    
 Milestone:  To Be Determined  |   Component:  parameter              
   Version:  release 1.34.0    |    Severity:  Problem                
Resolution:                    |    Keywords:  parameter keyword c4180
-------------------------------+--------------------------------------------
Comment (by anonymous):

 I get a similar problem, this is the simplest code to reproduce it (in
 msvc-8.0)
 {{{
 #include <boost/bind.hpp>

 template<typename T>
 struct Foo
 {
    Foo(T const& t_) : t(t_) {}
    T t;
 };

 typedef Foo<int> BarT;
 //typedef int Bar;

 class Moo
 {
 public:
    BarT GetBar ()
    {
       return BarT(42);
    }
 };

 int main()
 {
    Moo moo;
    boost::bind(&Moo::GetBar, moo);
 }
 }}}

 and the warning:

 {{{
 1>boost\boost.1.34.1\boost\boost\bind.hpp(1575) : warning C4180: qualifier
 applied to function type has no meaning; ignored
 1>        boost\boost.1.34.1\boost\boost\bind.hpp(1609) : see reference to
 class template instantiation 'boost::_bi::add_cref<Pm,I>' being compiled
 1>        with
 1>        [
 1>            Pm=Foo<int> (__thiscall Moo::* )(void),
 1>            I=1
 1>        ]
 1>        test1\test1.cpp(25) : see reference to class template
 instantiation 'boost::_bi::dm_result<Pm,A1>' being compiled
 1>        with
 1>        [
 1>            Pm=BarT (__thiscall Moo::* )(void),
 1>            A1=Moo
 1>        ]
 }}}

 The compiler seems to be choosing the member specialisation of add_cref:

 {{{
 template< class M, class T > struct add_cref< M T::*, 1 >
 {
     typedef M const & type; // line 1575
 };
 }}}

 rather than the member function specialisation:

 {{{
 template< class R, class T > struct add_cref< R (T::*) (), 1 >
 {
     typedef void type; // line 1580
 };
 }}}

 If you change the typedef of Bar to the int, all is well.

-- 
Ticket URL: <http://svn.boost.org/trac/boost/ticket/1097#comment:2>
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