std::mem_fun_ref
Defined in header
<functional>
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template< class Res, class T >
std::mem_fun_ref_t<Res,T> mem_fun_ref( Res (T::*f)() ); |
(1) | (until C++17) (deprecated since C++11) |
template< class Res, class T >
std::const_mem_fun_ref_t<Res,T> mem_fun_ref( Res (T::*f)() ); |
(1) | (until C++17) (deprecated since C++11) |
template< class Res, class T, class Arg >
std::mem_fun1_ref_t<Res,T,Arg> mem_fun_ref( Res (T::*f)(Arg) ); |
(2) | (until C++17) (deprecated since C++11) |
template< class Res, class T, class Arg >
std::const_mem_fun1_ref_t<Res,T,Arg> mem_fun_ref( S (T::*f)(Arg) ); |
(2) | (until C++17) (deprecated since C++11) |
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.
Contents |
[edit] Parameters
f | - | pointer to a member function to create a wrapper for |
[edit] Return value
A function object wrapping f
.
[edit] Exceptions
(none)
[edit] 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.
[edit] 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
[edit] See also
(until C++17)
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creates a wrapper from a pointer to member function, callable with a pointer to object (function template) |