help

hi
   i am a freshmen, i have a question about c++ stl.

   first, i defined a struct PtrChannelExist and two functions:
    SearchNodePtr isExistNodePtr

   secondly, when I compile my project ver1.0 by VC6.0 in the
platform WindowXP.

   the compiler indicated all is OK.

struct PtrChannelExist:
public binary_function<CChannel*,long,bool>{
    bool operator()(const CChannel* lhs,const long rhs)const
    {
        return (lhs->m_lExternalChannelID) == rhs;
    }
};

inline
channelPtrIt SearchNodePtr(ChannelPtrContainer& container,const long&
nodeID)
{
    return
find_if(container.begin(),container.end(),bind2nd(PtrChannelExist(),nodeID));
}

inline
BOOL isExistNodePtr(const long& nodeID,ChannelPtrContainer& container)
{
    BOOL isOk = false;
    if (CheckNode(nodeID))
    {
        channelPtrIt it = SearchNodePtr(container,nodeID);
        if ((it != container.end()) && (*it)->m_bChannelState)
            isOk = true;
    }

    return isOk;
}

but , after i updated the struct PtrChannelExist and two
functions:
    SearchNodePtr , the compiler indicated something were wrong.

template <typename OP>
class Xbinder2nd:
public unary_function<typename OP::first_argument_type,
                    typename OP::result_type>
{
protected:
    OP _op;
    typename OP::second_argument_type _n;

public:
    Xbinder2nd(const OP& op,const typename OP::second_argument_type& n)
        :_op(op),_n(n) {}

    typename OP::result_type //return type
        operator()(const typename OP::first_argument_type& x)const
    {
        return _op((*x)->m_lExternalChannelID,_n);
    }
};

template<typename OP, typename T>
inline
Xbinder2nd<OP> Xbind2nd(const OP& op,const T& n)
{
    typedef typename OP::second_argument_type OpSat;
    return Xbinder2nd<OP>(op,(OpSat)n);
}

template<typename elementT,typename T>
inline
T::iterator SearchNodePtr(T container,elementT nodeID)
{
    T::iterator findIt =
find_if(container.begin(),container.end(),bind2nd(equal<T::iterator,long>(),nodeID));
    return findIt;
}

template<typename elementT,typename T>
inline
BOOL isExistNodePtr(elementT& nodeID,T& container)
{
    return ((SearchNodePointer(container,nodeID) != container.end()) ?
true : false);
}

these are error message:

...\struct.h(266) : error C2780: 'bool __cdecl
std::equal(_II1,_II1,_II2,_Pr)' : expects 4 arguments - 0 provided
d:\program files\microsoft visual studio\vc98\include\xutility(33) :
see declaration of 'equal' comultiplayer\struct.h(274) : see
reference to function template instantiation 'class CChannel **__cdecl
SearchNodePointer(class std::vector<class CChannel *,class
std::allocator<class
 CChannel *> >,long) ' being compiled
comultiplayer\struct.h(266) : error C2780: 'bool __cdecl
std::equal(_II1,_II1,_II2)' : expects 3 arguments - 0 provided
        d:\program files\microsoft visual studio\vc98\include
\xutility(29) : see declaration of 'equal'
       \comultiplayer\struct.h(274) : see reference to function
template instantiation 'class CChannel **__cdecl
SearchNodePointer(class std::vector<class CChannel *,class
std::allocator<class
 CChannel *> >,long) ' being compiled