pointer-to-binary-function-class.md

description	Learn more about: pointer_to_binary_function Class
title	pointer_to_binary_function Class
ms.date	02/21/2019
f1_keywords	functional/std::pointer_to_binary
helpviewer_keywords	pointer_to_binary_function function pointer_to_binary_function class
ms.assetid	fb50599f-bcb3-4076-a669-6dcc3eb189a5

pointer_to_binary_function Class

Converts a binary function pointer into an adaptable binary function. Deprecated in C++11, removed in C++17.

Syntax

template <class Arg1, class Arg2, class Result>
class pointer_to_binary_function
    : public binary_function <Arg1, Arg2, Result>
{
    explicit pointer_to_binary_function(
        Result(*pfunc)(Arg1, Arg2));
    Result operator()(Arg1 left, Arg2 right) const;
};

Parameters

pfunc
The binary function to be converted.

left
The left object that the *pfunc is called on.

right
The right object that the *pfunc is called on.

Return Value

The class template stores a copy of pfunc. It defines its member function operator() as returning (* pfunc)(Left, right).

Remarks

A binary function pointer is a function object and may be passed to any C++ Standard Library algorithm that is expecting a binary function as a parameter, but it is not adaptable. To use it with an adaptor, such as binding a value to it or using it with a negator, it must be supplied with the nested types first_argument_type, second_argument_type, and result_type that make such an adaptation possible. The conversion by pointer_to_binary_function allows the function adaptors to work with binary function pointers.

Example

The constructor of pointer_to_binary_function is rarely used directly. See the helper function ptr_fun for an example of how to declare and use the pointer_to_binary_function adaptor predicate.