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  1. #include <functional>
  2. #include <iostream>
  3.  
  4. int f(int, int) { return 1; }
  5. int g(int, int) { return 2; }
  6. void test(std::function<int(int, int)> const& arg)
  7. {
  8.     std::cout << "test function: ";
  9.     if (arg.target<std::plus<int>>())
  10.         std::cout << "it is plus\n";
  11.     if (arg.target<std::minus<int>>())
  12.         std::cout << "it is minus\n";
  13.  
  14.     int (*const* ptr)(int, int) = arg.target<int(*)(int, int)>();
  15.     if (ptr && *ptr == f)
  16.         std::cout << "it is the function f\n";
  17.     if (ptr && *ptr == g)
  18.         std::cout << "it is the function g\n";
  19. }
  20.  
  21. class foo {
  22.  
  23. public:
  24.  
  25. 	void some_function(int) {
  26.  
  27. 	}
  28.  
  29. 	foo() {
  30. 		const auto func = std::function<void(int)> { [this](int i) {
  31. 			this->some_function(i);
  32. 		}};
  33. 		_member = func;
  34.  
  35. 		std::cout << "hello " << _member.target<decltype(func)>() << std::endl;
  36. 	}
  37. 	std::function<void(int)> _member;	
  38. };
  39. int main()
  40. {
  41. 	foo bar {};
  42. }
Success #stdin #stdout 0.01s 5320KB
comments (?)
stdin 
Standard input is empty
stdout 
hello 0
https://ideone.com/gk6lc2
language:
C++14 (gcc 8.3)
created:
2 days ago
visibility:
public

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