std::mem_fun_ref
Defined in header <functional> | ||
---|---|---|
template< class Res, class T >
std::mem_fun_ref_t<Res,T> mem_fun_ref( Res (T::*f)() );
| (1) | (deprecated in C++11) (removed in C++17) |
template< class Res, class T >
std::const_mem_fun_ref_t<Res,T> mem_fun_ref( Res (T::*f)() );
| (1) | (deprecated in C++11) (removed in C++17) |
template< class Res, class T, class Arg >
std::mem_fun1_ref_t<Res,T,Arg> mem_fun_ref( Res (T::*f)(Arg) );
| (2) | (deprecated in C++11) (removed in C++17) |
template< class Res, class T, class Arg >
std::const_mem_fun1_ref_t<Res,T,Arg> mem_fun_ref( S (T::*f)(Arg) );
| (2) | (deprecated in C++11) (removed in C++17) |
Creates a member function wrapper object, deducing the target type from the template arguments. The wrapper object expects a reference to an object of type T
as the first parameter to its operator()
.
1) Effectively calls std::mem_fun_ref_t<S,T>(f)
or std::const_mem_fun_ref_t<S,T>(f)
.
2) Effectively calls std::mem_fun1_ref_t<S,T>(f)
or std::const_mem_fun1_ref_t<S,T>(f)
.
This function and the related types were deprecated in C++11 and removed in C++17 in favor of the more general std::mem_fn
and std::bind
, both of which create callable adapter-compatible function objects from member functions.
Parameters
f | - | pointer to a member function to create a wrapper for |
Return value
A function object wrapping f
.
Exceptions
(none).
Notes
The difference between std::mem_fun
and std::mem_fun_ref
is that the former produces an function wrapper that expects a pointer to an object, whereas the latter -- a reference.
Example
uses std::mem_fun_ref to bind std::string's member function .size().
#include <functional>
#include <vector>
#include <string>
#include <iterator>
#include <algorithm>
#include <iostream>
int main()
{
std::vector<std::string> v = {"once", "upon", "a", "time"};
std::transform(v.begin(), v.end(),
std::ostream_iterator<std::size_t>(std::cout, " "),
std::mem_fun_ref(&std::string::size));
}
Output:
4 4 1 4
See also
(deprecated in C++11)(removed in C++17) | creates a wrapper from a pointer to member function, callable with a pointer to object (function template) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
http://en.cppreference.com/w/cpp/utility/functional/mem_fun_ref