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# std::ptr_fun

From cppreference.com
< cpp‎ | utility‎ | functional

Defined in header `<functional>` |  |
template< class Arg, class Result > std::pointer_to_unary_function<Arg,Result> ptr_fun( Result (*f)(Arg) ); | (1) | (until C++17) (deprecated since C++11)
template< class Arg1, class Arg2, class Result > std::pointer_to_binary_function<Arg1,Arg2,Result> ptr_fun( Result (*f)(Arg1, Arg2) ); | (2) | (until C++17) (deprecated since C++11)

Creates a function wrapper object (either std::pointer_to_unary_function or std::pointer_to_binary_function), deducing the target type from the template arguments.

1) Effectively calls std::pointer_to_unary_function<Arg,Result>(f).

2) Effectively calls std::pointer_to_binary_function<Arg1,Arg2,Result>(f).

This function and the related types are deprecated as of C++11 in favor of the more general std::function and std::ref, both of which create callable adapter-compatible function objects from plain functions.

### [edit] Parameters

f | - | pointer to a function to create a wrapper for

### [edit] Return value

A function object wrapping `f`.

### [edit] Exceptions

(none)

### [edit] Example

Run this code

    #include <string>
    #include <iostream>
    #include <algorithm>
    #include <functional>

    bool isvowel(char c)
    {
        return std::string("aeoiuAEIOU").find(c) != std::string::npos;
    }

    int main()
    {
        std::string s = "Hello, world!";
        std::copy_if(s.begin(), s.end(), std::ostreambuf_iterator<char>(std::cout),
                     std::not1(std::ptr_fun(isvowel)));
    // C++11 alternatives:
    //               std::not1(std::cref(isvowel)));
    //               std::not1(std::function<bool(char)>(isvowel)));

    }

Output:

    Hll, wrld!

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