C++: need help with boost::bind



  •   template <typename T>
        bool filterOut(  T * const who, bool (T::*func)(Object::Ptr, ObjectInfo::Type) const  )
      {
        std::vector<Object::Ptr>::iterator it = std::partition( m_objects.begin(), m_objects.end(), boost::bind( (who->*func), _2, m_objectType ) );

        m_objects.erase( it, m_objects.end() );  

        ... 

     } 

    m_objects is a private std::vector<Object::Ptr>

    m_objectType is a private ObjectInfo::Type

    Object::Ptr is a Boost shared pointer for Object class :

    typedef boost::shared_ptr<Object> Ptr;


    called as :

    objectSet->filterOut<Filter>( this, &Filter::isObjectOfType )

     

    definition of isObjectOfType :

    class Filter { 

    public: 

      bool isObjectOfType(
        Object::Ptr object, ObjectInfo::Type type
      ) const;
     }

     

     



  • As fascinating as all that may be, you don't appear to have a question.



  • @asuffield said:

    As fascinating as all that may be, you don't appear to have a question.

     

    This does not compile. error is somwhere in boost::bind.

    After couple of hours at the monitor I just don't see it.
     



  • @Nelle said:

    @asuffield said:

    As fascinating as all that may be, you don't appear to have a question.

     

    This does not compile. error is somwhere in boost::bind.

    After couple of hours at the monitor I just don't see it.
     

     

    throws error somewhere in boost::bind.

    Compiling...

    error
    C2780: '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)' : expects 2 arguments - 3 provided
        ... \boost\boost\bind.hpp(1628) : see declaration of 'boost::bind'
           
    Filter.cpp(124) : see reference to function template instantiation
    'bool ObjectSet::filterOut<Filter>(T const ,bool (__thiscall
    Filter::
    )(Object::Ptr,ObjectInfo::Type) const)' being compiled
            with
            [
                T=Filter
            ]


    After couple of hours at the monitor I just don't see it.

     



  • If you're using MSVC 7/8 (as it looks like) Google shows it may be a compiler issue, for example. Try using another compiler, even if its just a small test snippet to see what works where, or spend a little more time on Google than I did and see if anyone has come up with a solution.



  • Just a wild guess: _1 instead of _2 ?



  • @ammoQ said:

    Just a wild guess: _1 instead of _2 ?

    good one :

    so the current status is :

    if I use boost::lambda::bind(func, who, _1, m_objectType) ( some Object::Ptr() ) in the testing function, it works, which means the bind is properly resolved to a method that has one Object::Ptr argument and returns a bool..

    all nice an well, but when I try to use the same bind here : 

    std::vector<Object::Ptr>::iterator it = std::partition( m_objects.begin(), m_objects.end(),  boost::lambda::bind(func, who, _1, m_objectType) ); 

    the compiler throws the following error :

    error C2664: 'bool (Object::Ptr,ObjectInfo::Type) const' : cannot convert parameter 1 from 'const rt2' to 'Object::Ptr'

     



  • @Nelle said:

    @ammoQ said:

    Just a wild guess: _1 instead of _2 ?

    good one :

    so the current status is :

    if I use boost::lambda::bind(func, who, _1, m_objectType) ( some Object::Ptr() ) in the testing function, it works, which means the bind is properly resolved to a method that has one Object::Ptr argument and returns a bool..

    all nice an well, but when I try to use the same bind here : 

    std::vector<Object::Ptr>::iterator it = std::partition( m_objects.begin(), m_objects.end(),  boost::lambda::bind(func, who, _1, m_objectType) ); 

    the compiler throws the following error :

    error C2664: 'bool (Object::Ptr,ObjectInfo::Type) const' : cannot convert parameter 1 from 'const rt2' to 'Object::Ptr'

     

     

    Finally solved it .....

    if someone runs into similar problem, just keep in mind that  

    boost::bind != boost::lambda::bind

    and when using both in one class be extra carefull, since _1 for lambda bind is defined in boost::lambda::_1,

    however _1 for boost bind is defined in ::_1 anonymous namespace .  gg


    p.s. ammoQ thnx for _2 -> _1 



  • @Nelle said:


    p.s. ammoQ thnx for _2 -> _1 

    That was too easy. I don't even know C++.
     


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