| Defined in header <functional> | ||||
|---|---|---|---|---|
| (1) | (until C++17) (deprecated since C++11) | ||
| (1) | (until C++17) (deprecated since C++11) | ||
| (2) | (until C++17) (deprecated since C++11) | ||
| (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.
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().
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | #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:
1 | 4 4 1 4 |
See also
| (until C++17) | creates a wrapper from a pointer to member function, callable with a pointer to object (function template) |
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