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  1. #include <iostream>
  2. #include <functional>
  3. #include <type_traits>
  4.  
  5. // TODO: provide your definition of what this actually is
  6. //  (sounds like you already have one)
  7. struct NATIVEVALUE {};
  8.  
  9.  
  10. // from your question
  11. typedef int (*EXTENSIONFUNCTION)(NATIVEVALUE args[]);
  12.  
  13.  
  14. // TODO: provide overloads for conversion of supported data
  15. //  types to the NATIVEVALUE construction.
  16. NATIVEVALUE nv_conv(int value)
  17. {
  18.     std::cout << __PRETTY_FUNCTION__ << '\n';
  19.     NATIVEVALUE nv = {};
  20.     return nv;
  21. }
  22.  
  23. NATIVEVALUE nv_conv(double dbl)
  24. {
  25.     std::cout << __PRETTY_FUNCTION__ << '\n';
  26.     NATIVEVALUE nv = {};
  27.     return nv;
  28. }
  29.  
  30. NATIVEVALUE nv_conv(unsigned int ui)
  31. {
  32.     std::cout << __PRETTY_FUNCTION__ << '\n';
  33.     NATIVEVALUE nv = {};
  34.     return nv;
  35. }
  36.  
  37. NATIVEVALUE nv_conv(char c)
  38. {
  39.     std::cout << __PRETTY_FUNCTION__ << '\n';
  40.     NATIVEVALUE nv = {};
  41.     return nv;
  42. }
  43.  
  44. // object wrapper for holding the callback and provide call-operator
  45. //  overloads (template and empty)
  46. struct Callable
  47. {
  48.     EXTENSIONFUNCTION m_pfn;
  49.  
  50.     Callable(EXTENSIONFUNCTION pfn) : m_pfn(pfn) {}
  51.  
  52.     template<class Arg, class... Args>
  53.     int operator()(Arg arg, Args... args)
  54.     {
  55.         std::cout << __PRETTY_FUNCTION__ << '\n';
  56.         NATIVEVALUE nv_args[] = { nv_conv(arg), nv_conv(args)... };
  57.         return m_pfn(nv_args);
  58.     }
  59.  
  60.     // no arg overload
  61.     int operator()()
  62.     {
  63.         std::cout << __PRETTY_FUNCTION__ << '\n';
  64.         return m_pfn(NULL);
  65.     }
  66. };
  67.  
  68. int nv_callback(NATIVEVALUE args[])
  69. {
  70.     std::cout << __PRETTY_FUNCTION__ << '\n';
  71.     return 0;
  72. }
  73.  
  74.  
  75. int main()
  76. {
  77.     auto fn = std::bind(Callable(nv_callback), 1, 2.0, 03, 4U, '5');
  78.     fn();
  79.  
  80.     auto fn2 = std::bind(Callable(nv_callback));
  81.     fn2();
  82.  
  83.     return 0;
  84. }
Success #stdin #stdout 0s 3296KB
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int Callable::operator()(Arg, Args ...) [with Arg = int; Args = {double, int, unsigned int, char}]
NATIVEVALUE nv_conv(int)
NATIVEVALUE nv_conv(double)
NATIVEVALUE nv_conv(int)
NATIVEVALUE nv_conv(unsigned int)
NATIVEVALUE nv_conv(char)
int nv_callback(NATIVEVALUE*)
int Callable::operator()()
int nv_callback(NATIVEVALUE*)
https://ideone.com/fJlkK6
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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