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  1. #include <iostream>
  2. using namespace std;
  3.  
  4. typedef void (*F)();
  5.  
  6. template<F f> struct Goal
  7. {
  8. 	Goal() { f(); }
  9. };
  10.  
  11. template<F f> struct Singleton
  12. {
  13. 	static Goal<f> instance;
  14. };
  15. template<F f> Goal<f> Singleton<f>::instance;
  16.  
  17. template<F f, Goal<f>* I> struct Instantiator {};
  18.  
  19. template<F f> struct Voila : Instantiator<f, &Singleton<f>::instance> {};
  20.  
  21. void foo() { cout << "foo" << endl; }
  22. void bar() { cout << "bar" << endl; }
  23. Voila<foo> voici;
  24.  
  25. int main() {
  26. 	Singleton<bar> tmp;
  27. 	return 0;
  28. }
Success #stdin #stdout 0s 3296KB
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foo
https://ideone.com/3Hkm9H
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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