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  1. #include <iostream>
  2.  
  3. int function(int arg) { return arg; }
  4. void function2() { std::cout << "void" << std::endl; }
  5.  
  6. template <typename T> class example;
  7. template <typename T_ret, typename... T_arg>
  8. class example <T_ret (*) (T_arg...)> {
  9. public:
  10. 	using type_f = T_ret (*) (T_arg...);
  11. };
  12.  
  13. template <typename T> 
  14. class caller {};
  15.  
  16. // for non-void:
  17. template <typename T_ret, typename... T_args> 
  18. class caller<T_ret(*)(T_args...)> {
  19.     T_ret (*m_p) (T_args... args);
  20. public:
  21.     T_ret call (T_args... args) {
  22.         return m_p(args...);
  23.     }
  24.     caller (T_ret (*p)(T_args...args)) : m_p(p) {}
  25. };
  26.  
  27. // for void:
  28. template <typename... T_args> 
  29. class caller<void(T_args...)> {
  30.     void (*m_p) (T_args... args);
  31. public:
  32.     void call (T_args... args) {
  33.         return m_p(args...);
  34.     }
  35.     caller (void (*p)(T_args...args)) : m_p(p) {}
  36. };
  37. typedef int (*function_int_t) (int arg);
  38. typedef void (*function_void_t) ();
  39. typedef example <function_int_t> example_int_t;
  40. typedef example <function_void_t> example_void_t;
  41.  
  42. int main()
  43. {
  44.     caller<function_int_t> c1(&function);
  45.     caller<function_void_t> c2(&function2);
  46.     caller<example_int_t::type_f> c3(&function);
  47.     caller<example_void_t::type_f> c4(&function2);
  48.     std::cout << c1.call(1) << std::endl;
  49.     c2.call();
  50.     std::cout << c3.call(2) << std::endl;
  51.     c4.call();
  52.     return 0;
  53. }
  54.  
Success #stdin #stdout 0s 3340KB
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https://ideone.com/TxYh3X
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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