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  1. #include <iostream>
  2. #include <utility>
  3.  
  4. void foo() {
  5. 	std::cout << "void foo()\n";
  6. }
  7.  
  8.  int bar(int u, char* c_str) {
  9.  	std::cout << "int bar(" << u << ", \"" << c_str << "\")\n";
  10.  	return u;
  11.  }
  12.  
  13. template<typename T>
  14. class WrapFuncObj;
  15.  
  16. template<typename T,  typename... Args>
  17. class WrapFuncObj<T(Args...)> {
  18.     T (*f)(Args...);
  19. public:
  20.     WrapFuncObj(T (*t)(Args...)) {
  21.         f = t;
  22.     }
  23.  
  24.     T operator()(Args&&... args) {
  25.         if(f != nullptr) {
  26.             return (*f)(std::forward<Args>(args)...);
  27.         } else {
  28.             return T();
  29.         }
  30.     }
  31. };
  32.  
  33. int main() {
  34. 	WrapFuncObj<void()> wrap_foo(&foo);
  35. 	wrap_foo();
  36.  
  37. 	WrapFuncObj<int(int, char*)> wrap_bar(&bar); 
  38. 	wrap_bar(0, "test");
  39.  
  40. 	WrapFuncObj<void()> wrap_null(nullptr);
  41. 	wrap_null(); // prints nothing.
  42. }
Success #stdin #stdout 0s 3412KB
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Standard input is empty
stdout
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void foo()
int bar(0, "test")
https://ideone.com/yk4YLA
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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