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  1. #include <iostream>
  2. #include <map>
  3.  
  4. std::map<void*, std::size_t> memory; // globally allocated memory map
  5. struct tag {}; // tag for placement new's so we don't overload the global ones
  6.  
  7. void* operator new(std::size_t size, const tag&)
  8. {
  9.     void* addr = malloc(size);
  10.     memory[addr] = size;
  11.     return addr;
  12. }
  13.  
  14. void* operator new[](std::size_t size, const tag&) // for arrays
  15. {
  16.     return operator new(size, tag());
  17. }
  18.  
  19. void operator delete(void *p) noexcept
  20. {
  21.     memory.erase(p);
  22.     free(p);
  23. }
  24.  
  25. void operator delete[](void *p) noexcept // for arrays
  26. {
  27.     operator delete(p);
  28. }
  29.  
  30. void display_memory()
  31. {
  32.     std::cout << "Allocated heap memory: " << std::endl;
  33.     for (auto && elem : memory)
  34.     {
  35.         std::cout << "\tADDR: " << elem.first << " "
  36.                   << "SIZE: "  << elem.second << std::endl;
  37.     }
  38. }
  39.  
  40. bool is_allocated(void* p)
  41. {
  42.     return (memory.find(p) != memory.end());
  43. }
  44.  
  45. int main()
  46. {
  47.     int *p = new(tag()) int[10];
  48.     char *c = new(tag()) char;
  49.  
  50.     // test if p is allocated
  51.     std::cout << std::boolalpha << "Allocated: "
  52.               << is_allocated(p) << std::endl;
  53.  
  54.     // display the allocated memory
  55.     display_memory();
  56.  
  57.     // remove p
  58.     delete[] p;
  59.  
  60.     // test again if p is allocated
  61.     std::cout << std::boolalpha << "Allocated: "
  62.               << is_allocated(p) << std::endl;
  63.  
  64.     display_memory();
  65.  
  66.     // remove c
  67.     delete c;
  68.  
  69.     display_memory();
  70. }
Success #stdin #stdout 0s 3232KB
comments (?)
stdin 
Standard input is empty
stdout 
Allocated: true
Allocated heap memory: 
	ADDR: 0x875e008 SIZE: 40
	ADDR: 0x875e058 SIZE: 1
Allocated: false
Allocated heap memory: 
	ADDR: 0x875e058 SIZE: 1
Allocated heap memory:
https://ideone.com/90dADP
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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