的boost ::绑定，这已经是必然

Question

我有一个Visual Studio 2008的C++应用程序，确实是这样的：

template< typename Fcn > 
inline void Bar(Fcn fcn) // line 84 
{ 
    fcn(); 
}; 

template< typename Fcn > 
inline void Foo(Fcn fcn) 
{ 
    // this works fine 
    Bar(fcn); 

    // this fails to compile 
    boost::bind(Bar, fcn)(); 
}; 

int main() 
{ 
    SYSTEM_POWER_STATUS_EX status = { 0 }; 
    Foo(boost::bind(::GetSystemPowerStatusEx, &status, true)); // line 160 
    return 0; 
} 

*到GetSystemPowerStatusEx（）的调用只是为了演示。在那里插入你最喜欢的电话，行为是一样的。

当我去编译这个，我得到84错误。我不是都张贴除非问，但他们开始与此：

1>.\MyApp.cpp(99) : error C2896: 'boost::_bi::bind_t<_bi::dm_result<MT::* ,A1>::type,boost::_mfi::dm<M,T>,_bi::list_av_1<A1>::type> boost::bind(M T::* ,A1)' : cannot use function template 'void Bar(Fcn)' as a function argument 
1>  .\MyApp.cpp(84) : see declaration of 'Bar' 
1>  .\MyApp.cpp(160) : see reference to function template instantiation 'void Foo<boost::_bi::bind_t<R,F,L>>(Fcn)' being compiled 
1>  with 
1>  [ 
1>   R=BOOL, 
1>   F=BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL), 
1>   L=boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>, 
1>   Fcn=boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>> 
1>  ] 

如果有人能指出我可能做错了，我将不胜感激。

---

编辑： 通过更改为：

boost::bind(Bar<Fcn>, fcn); 

通过大家的建议，我只剩下1个错误：

1>boost/bind/bind.hpp(246) : error C2664: 'void (Fcn)' : cannot convert parameter 1 from 'int' to 'boost::_bi::bind_t<R,F,L>' 
1>  with 
1>  [ 
1>   Fcn=boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>> 
1>  ] 
1>  and 
1>  [ 
1>   R=BOOL, 
1>   F=BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL), 
1>   L=boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>> 
1>  ] 
1>  No constructor could take the source type, or constructor overload resolution was ambiguous 
1>  boost/bind/bind_template.hpp(20) : see reference to function template instantiation 'void boost::_bi::list1<A1>::operator()<void(__cdecl *)(Fcn),boost::_bi::list0>(boost::_bi::type<T>,F &,A &,int)' being compiled 
1>  with 
1>  [ 
1>   A1=boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>>, 
1>   Fcn=boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>>, 
1>   T=void, 
1>   F=void (__cdecl *)(boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>>), 
1>   A=boost::_bi::list0 
1>  ] 
1>  boost/bind/bind_template.hpp(18) : while compiling class template member function 'void boost::_bi::bind_t<R,F,L>::operator()(void)' 
1>  with 
1>  [ 
1>   R=void, 
1>   F=void (__cdecl *)(boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>>), 
1>   L=boost::_bi::list1<boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>>> 
1>  ] 
1>  .\MyApp.cpp(99) : see reference to class template instantiation 'boost::_bi::bind_t<R,F,L>' being compiled 
1>  with 
1>  [ 
1>   R=void, 
1>   F=void (__cdecl *)(boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>>), 
1>   L=boost::_bi::list1<boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>>> 
1>  ] 
1>  .\MyApp.cpp(160) : see reference to function template instantiation 'void Foo<boost::_bi::bind_t<R,F,L>>(Fcn)' being compiled 
1>  with 
1>  [ 
1>   R=BOOL, 
1>   F=BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL), 
1>   L=boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>, 
1>   Fcn=boost::_bi::bind_t<BOOL,BOOL (__cdecl *)(PSYSTEM_POWER_STATUS_EX,BOOL),boost::_bi::list2<boost::_bi::value<_SYSTEM_POWER_STATUS_EX *>,boost::_bi::value<bool>>> 
1>  ] 

感谢， PaulH

Answer 1

你需要指定模板参数。

boost::bind(Bar<Fcn>, fcn)(); 

编辑：此外，人们必须使用boost ::保护，以防止从FCN得到评估。请参阅Paul对正确用法的评论。

Answer 2

问题是Bar不是一个函数。然而，Bar<Fcn>是。尝试

boost::bind(Bar<Fcn>, fcn)(); 

Answer 3

尝试 的boost ::绑定（酒吧< FCN>，FCN）（）;