Sandbox/CostOfUsingStatic.cpp

   1 #include "CostOfUsingStatic.h"
   2
   3 #include <iostream>
   4 using namespace std;
   5
   6 // From: https://www.youtube.com/watch?v=B3WWsKFePiM
   7
   8 namespace CostOfUsingStatic
   9 {
  10     struct C
  11     {
  12         // This call is costy.
  13         static const string& magic_static()
  14         {
  15             // Static variables are very costly.
  16             // Each time a thread safe comparison must be executed.
  17             static const string s = "bob";
  18             return s;
  19         }
  20
  21         const string& s = magic_static();
  22
  23         const string& magic_static_ref()
  24         {
  25             return s;
  26         }
  27     };
  28 }
  29
  30 void CostOfUsingStatic::tests()
  31 {
  32     C c;
  33     size_t total_size = 0;
  34
  35     for (int i = 0; i < 2000000000; ++i)
  36     {
  37         total_size += c.magic_static_ref().size() + i; // It takes ~500 ms.
  38         //total_size += C::magic_static().size() + i; // It takes ~1200 ms.
  39     }
  40
  41     //return total_size;
  42
  43     cout << "total size: " << total_size << endl;
  44 }