An adapter class that allows a const member function that takes no arguments to be called as a unary function object when initialized with a reference argument.
template<class Result, class Type>
class const_mem_fun_ref_t
: public unary_function<Type, Result>
{
explicit const_mem_fun_t(Result ( Type::* _Pm)( ) const );
Result operator()(
const Type& _Left
) const;
};
Parameters
_Pm
A pointer to the member function of class Type to be converted to a function object._Left
The object that the _Pm member function is called on.
Return Value
An adaptable unary function.
Remarks
The template class stores a copy of _Pm, which must be a pointer to a member function of class Type, in a private member object. It defines its member function operator() as returning (_Left.* _Pm)() const.
Example
The constructor of const_mem_fun_ref_t is not usually used directly; the helper function mem_fun_ref is used to adapt member functions. See mem_fun_ref for an example of how to use member function adaptors.
Requirements
Header: <functional>
Namespace: std