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  1. #include <iostream>
  2. #include <map>
  3.  
  4. namespace detail {
  5.     struct FuncPtrMap {
  6.         friend struct FuncPtrRegisterer;
  7.         typedef void(*FuncPtr)();
  8.         static std::map<std::string, FuncPtr> const &getMap() {
  9.             return getWritableMap();
  10.         }
  11.  
  12.     private:
  13.         // SIOF-proof singleton
  14.         static std::map<std::string, FuncPtr> &getWritableMap() {
  15.             static std::map<std::string, FuncPtr> theMap;
  16.             return theMap;
  17.         }
  18.     };
  19.  
  20.     // Each static instance will register one function pointer
  21.     struct FuncPtrRegisterer {
  22.         FuncPtrRegisterer(FuncPtrMap::FuncPtr funcPtr, char const *funcName) {
  23.             FuncPtrMap::getWritableMap().insert(std::make_pair(funcName, funcPtr));
  24.         }
  25.     };
  26. }
  27.  
  28. // Public access to the function pointers map
  29. typedef std::map<std::string, detail::FuncPtrMap::FuncPtr> FunctionPointersMap;
  30. FunctionPointersMap const &gFunctionPointersMap = detail::FuncPtrMap::getMap();
  31.  
  32. #define DO_CAT(A, B) A##B
  33. #define CAT(A, B) DO_CAT(A, B)
  34.  
  35. // Registering macro : defines a static registerer
  36. // with a (hopefully) unique name.
  37. #define REGISTER_FUNC(NAME) detail::FuncPtrRegisterer \
  38.     CAT(fpreg, __COUNTER__) (&NAME, #NAME)
  39.  
  40.  
  41. //
  42. // Test
  43. //
  44.  
  45. void myFunc1() {
  46.     std::cout << "func1\n";
  47. }
  48. REGISTER_FUNC(myFunc1);
  49.  
  50. void myFunc2() {
  51.     std::cout << "func2\n";
  52. }
  53. REGISTER_FUNC(myFunc2);
  54.  
  55. int main()
  56. {
  57.     for(FunctionPointersMap::const_iterator
  58.         ite = gFunctionPointersMap.begin(),
  59.         end = gFunctionPointersMap.end();
  60.         ite != end; ++ite) {
  61.         std::cout << "Calling " << ite->first << " : ";
  62.         ite->second();
  63.     }
  64.  
  65.     return 0;
  66. }
Success #stdin #stdout 0s 3432KB
comments (?)
stdin 
Standard input is empty
stdout 
Calling myFunc1 : func1
Calling myFunc2 : func2
https://ideone.com/XYDmVQ
language:
C++ (gcc 8.3)
created:
9 years ago
visibility:
public

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