const_mem_fun_t Class

Article
08/03/2021

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. Deprecated in C++11, removed in C++17.

Syntax

template <class Result, class Type>
class const_mem_fun_t : public unary_function <Type *, Result>
{
    explicit const_mem_fun_t(Result (Type::* Pm)() const);
    Result operator()(const Type* Pleft) const;
};

Parameters

Pm
A pointer to the member function of class Type to be converted to a function object.

Pleft
The object that the Pm member function is called on.

Return Value

An adaptable unary function.

Remarks

The class template 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 (Pleft->* Pm)() const.

Example

The constructor of const_mem_fun_t is not usually used directly; the helper function mem_fun is used to adapt member functions. See mem_fun for an example of how to use member function adaptors.

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