Clever Geek Handbook

VC2013: function from binding does not compile

Here's a short example:

class A {};

class S {};

class B
{
public:
    typedef std::function <bool (A& retVal)> property_getter_t;
    typedef std::function<bool (B* /*this*/, const std::shared_ptr<S>&, A& retVal)> SettingsPropGetter;

    void DefineSettingsProperty(const std::wstring& name, const SettingsPropGetter& getter)
    {
        auto fn_g = std::bind(getter, this, std::placeholders::_1, std::placeholders::_2);
        auto fn_gg = std::bind(&B::GetterHandler, this, fn_g, std::placeholders::_1);

        property_getter_t x = fn_gg;  // PROBLEM IS HERE
    }

    bool GetterHandler(const std::function<bool (const std::shared_ptr<S>&, A&)>& getter, A& a)
    {
        std::shared_ptr <S> s;
        return getter (s, a);
    }
};

The code is compiled for VC2010. In VC2013, I get a huge batch of errors all the time.

What happened? Can this be fixed somehow?

Here are the errors:

1>c:\program files (x86)\microsoft visual studio 12.0\vc\include\tuple(540): error C2504: 'std::tuple_element<0,std::tuple<>>' : base class undefined
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(900) : see reference to class template instantiation 'std::tuple_element<1,_Ftuple>' being compiled
1>          with
1>          [
1>              _Ftuple=std::tuple<A &>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(946) : see reference to class template instantiation 'std::_Fixarg_ret_base<_Placeholder,_Funx,std::_Ph<2>,_Ftuple>' being compiled
1>          with
1>          [
1>              _Funx=std::function<bool (B *,const std::shared_ptr<S> &,A &)>
1>  ,            _Ftuple=std::tuple<A &>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(975) : see reference to class template instantiation 'std::_Fixarg_ret<_Funx,std::_Ph<2> &,_Ftuple>' being compiled
1>          with
1>          [
1>              _Funx=std::function<bool (B *,const std::shared_ptr<S> &,A &)>
1>  ,            _Ftuple=std::tuple<A &>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\xrefwrap(58) : see reference to class template instantiation 'std::_Do_call_ret<false,_Ret,std::function<bool (B *,const std::shared_ptr<S> &,A &)>,std::tuple<B *,std::_Ph<1>,std::_Ph<2>>,std::tuple<A &>,std::_Arg_idx<0,1,2>>' being compiled
1>          with
1>          [
1>              _Ret=void
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\xrefwrap(118) : see reference to class template instantiation 'std::_Result_of<_Fty,A &>' being compiled
1>          with
1>          [
1>              _Fty=std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(914) : see reference to class template instantiation 'std::result_of<_Bind_t (A &)>' being compiled
1>          with
1>          [
1>              _Bind_t=std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(924) : see reference to class template instantiation 'std::_Call_ret<_Barg,std::tuple<A &>,std::_Arg_idx<0>>' being compiled
1>          with
1>          [
1>              _Barg=std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(946) : see reference to class template instantiation 'std::_Fixarg_ret_base<_Bind_expression,_Funx,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &>,_Ftuple>' being compiled
1>          with
1>          [
1>              _Funx=std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &> &
1>  ,            _Ftuple=std::tuple<A &>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(1148) : see reference to class template instantiation 'std::_Fixarg_ret<std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &> &,_Ty,std::tuple<A &>>' being compiled
1>          with
1>          [
1>              _Ty=std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(1137) : see reference to function template instantiation 'bool std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>::_Do_call<A,0,1,2>(std::tuple<A &>,std::_Arg_idx<0,1,2>)' being compiled
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(1137) : see reference to function template instantiation 'bool std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>::_Do_call<A,0,1,2>(std::tuple<A &>,std::_Arg_idx<0,1,2>)' being compiled
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\xrefwrap(283) : see reference to function template instantiation 'bool std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>::operator ()<A&>(A &)' being compiled
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\xrefwrap(283) : see reference to function template instantiation 'bool std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>::operator ()<A&>(A &)' being compiled
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(228) : see reference to function template instantiation '_Ret std::_Callable_obj<std::_Bind<true,_Ret,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>,false>::_ApplyX<_Rx,A&>(A &)' being compiled
1>          with
1>          [
1>              _Ret=bool
1>  ,            _Rx=bool
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(228) : see reference to function template instantiation '_Ret std::_Callable_obj<std::_Bind<true,_Ret,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>,false>::_ApplyX<_Rx,A&>(A &)' being compiled
1>          with
1>          [
1>              _Ret=bool
1>  ,            _Rx=bool
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(226) : while compiling class template member function 'bool std::_Func_impl<_MyWrapper,_Alloc,_Ret,A &>::_Do_call(A &)'
1>          with
1>          [
1>              _Alloc=std::allocator<std::_Func_class<bool,A &>>
1>  ,            _Ret=bool
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(495) : see reference to class template instantiation 'std::_Func_impl<_MyWrapper,_Alloc,_Ret,A &>' being compiled
1>          with
1>          [
1>              _Alloc=std::allocator<std::_Func_class<bool,A &>>
1>  ,            _Ret=bool
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(396) : see reference to function template instantiation 'void std::_Func_class<_Ret,A &>::_Do_alloc<_Myimpl,std::_Bind<true,_Ret,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>&,_Alloc>(_Fty,_Alloc)' being compiled
1>          with
1>          [
1>              _Ret=bool
1>  ,            _Alloc=std::allocator<std::_Func_class<bool,A &>>
1>  ,            _Fty=std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &> &
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(396) : see reference to function template instantiation 'void std::_Func_class<_Ret,A &>::_Do_alloc<_Myimpl,std::_Bind<true,_Ret,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>&,_Alloc>(_Fty,_Alloc)' being compiled
1>          with
1>          [
1>              _Ret=bool
1>  ,            _Alloc=std::allocator<std::_Func_class<bool,A &>>
1>  ,            _Fty=std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &> &
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(385) : see reference to function template instantiation 'void std::_Func_class<_Ret,A &>::_Reset_alloc<std::_Bind<true,_Ret,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>&,std::allocator<std::_Func_class<_Ret,A &>>>(_Fty,_Alloc)' being compiled
1>          with
1>          [
1>              _Ret=bool
1>  ,            _Fty=std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &> &
1>  ,            _Alloc=std::allocator<std::_Func_class<bool,A &>>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(385) : see reference to function template instantiation 'void std::_Func_class<_Ret,A &>::_Reset_alloc<std::_Bind<true,_Ret,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>&,std::allocator<std::_Func_class<_Ret,A &>>>(_Fty,_Alloc)' being compiled
1>          with
1>          [
1>              _Ret=bool
1>  ,            _Fty=std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &> &
1>  ,            _Alloc=std::allocator<std::_Func_class<bool,A &>>
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(671) : see reference to function template instantiation 'void std::_Func_class<_Ret,A &>::_Reset<std::_Bind<true,_Ret,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>&>(_Fty)' being compiled
1>          with
1>          [
1>              _Ret=bool
1>  ,            _Fty=std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &> &
1>          ]
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(671) : see reference to function template instantiation 'void std::_Func_class<_Ret,A &>::_Reset<std::_Bind<true,_Ret,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>&>(_Fty)' being compiled
1>          with
1>          [
1>              _Ret=bool
1>  ,            _Fty=std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &> &
1>          ]
1>          c:\work\source\test.cpp(29) : see reference to function template instantiation 'std::function<bool (A &)>::function<std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>&>(_Fx)' being compiled
1>          with
1>          [
1>              _Fx=std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &> &
1>          ]
1>          c:\work\source\test.cpp(29) : see reference to function template instantiation 'std::function<bool (A &)>::function<std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &>&>(_Fx)' being compiled
1>          with
1>          [
1>              _Fx=std::_Bind<true,bool,std::_Pmf_wrap<bool (__thiscall B::* )(const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &),bool,B,const std::function<bool (const std::shared_ptr<S> &,A &)> &,A &>,B *const ,std::_Bind<false,void,const B::SettingsPropGetter &,B *const ,std::_Ph<1> &,std::_Ph<2> &> &,std::_Ph<1> &> &
1>          ]
1>c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(900): error C2039: 'type' : is not a member of 'std::tuple_element<1,_Ftuple>'
1>          with
1>          [
1>              _Ftuple=std::tuple<A &>
1>          ]
1>c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(900): error C2146: syntax error : missing ',' before identifier 'type'
1>c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(900): error C2065: 'type' : undeclared identifier
1>c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(900): error C2977: 'std::add_reference' : too many template arguments
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\type_traits(180) : see declaration of 'std::add_reference'
1>c:\program files (x86)\microsoft visual studio 12.0\vc\include\functional(900): error C2955: 'std::add_reference' : use of class template requires template argument list
1>          c:\program files (x86)\microsoft visual studio 12.0\vc\include\type_traits(180) : see declaration of 'std::add_reference'

c: \ work \ source \ test.cpp (29) is my source file (where the comment "PROBLEM IS HERE").

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1 answer


I usually quote the standard, but the standard is particularly dense here, so I'll just explain what's going on.

std::bind

does something special when you pass an argument to bind if that argument is a function object returned by a previous call std::bind

. Let's assume you did this:

auto f = std::bind(foo, std::placeholders::_1);
auto g = std::bind(bar, f, std::placeholders::_1);

Then the call is g(a)

roughly equivalent to

bar(foo(a), a)

but not



bar(f, a)

Demo .

That is, if you pass something that is returned bind

in bind

as its associated argument, what will be passed to the function you are binding is the result of calling that binding expression. It's kind of a composition.

However, in your code, you don't actually want composition to take place. (This composition caused g ++ to emit 320+ lines of error when I tried to call yours fn_gg

on A

. The clan with libC ++ only printed 10 lines, thankfully.) You want to fn_g

be treated the same as a normal argument. Therefore, you can wrap it in std::function

:

std::function<bool (const std::shared_ptr<S>&, A&)> fn_g = std::bind(getter, this, std::placeholders::_1, std::placeholders::_2);
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