fork(1) download
copy 
  1. #include <iostream>
  2. #include <unordered_map>
  3. #include <vector>
  4. #include <thread>
  5. #include <algorithm>
  6. #include <mutex>
  7. using namespace std;
  8.  
  9. class single
  10. {
  11. public:
  12. 	// Every thread needs to call this to get its individual instance
  13. 	static single* getInstance( unsigned int threadId );
  14.  
  15. 	static void print( unsigned int threadId )
  16. 	{
  17. 		std::cout << "threadId:"	<< threadId << ", Singleton: " << _instances[threadId] << std::endl;
  18. 	}
  19.  
  20. protected:
  21. 	// Made protected not private so that singleton can be subclassed
  22. 	single();											// Clients cant construct objects directly
  23. 	~single();											// cannot be destroyed by clients
  24.  
  25. 	single(const single &) = delete;		 			// non-copyable
  26. 	single& operator=(const single &) = delete; 		// can't be copy assigned
  27. 	single(single &&) = delete;							// non-move constructible
  28. 	single & operator=(single && ) = delete;			// non-move assignable
  29.  
  30. private:
  31. 	static std::unordered_map<unsigned,single*> _instances;
  32. 	static std::mutex _lock;
  33.  
  34. };
  35.  
  36. std::mutex single::_lock;
  37. std::unordered_map<unsigned,single*> single::_instances;
  38.  
  39. single::single(){}
  40.  
  41. single::~single(){}
  42.  
  43. single* single::getInstance( unsigned int threadId )
  44. {
  45. 	if( _instances.count( threadId ) == 0 )
  46. 	{
  47. 		std::lock_guard<std::mutex> lg(_lock);
  48. 		if( _instances.count( threadId ) == 0 )
  49. 		{
  50. 			_instances[threadId] = new single;
  51. 			std::cout <<"Created By ThreadId: " << threadId <<std::endl;
  52. 		}
  53. 	}
  54.  
  55. 	return _instances[threadId];
  56. }
  57.  
  58. void Run( unsigned int threadId )
  59. {
  60. 	single::getInstance(threadId)->print(threadId);
  61. }
  62.  
  63. int main()
  64. {
  65. 	std::vector<std::thread> workers;
  66. 	const unsigned threadCount = 16;
  67.  
  68. 	for( auto i = 0; i != threadCount; ++i )
  69. 	{
  70. 		workers.push_back( std::thread( Run, i ) );
  71. 	}
  72.  
  73. 	for_each( workers.begin(), workers.end(), std::mem_fn(&thread::join) );
  74.  
  75. 	return 0;
  76. }
Runtime error #stdin #stdout #stderr 0s 134528KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
Standard output is empty
stderr
copy 
terminate called after throwing an instance of 'std::system_error'
  what():  Resource temporarily unavailable
https://ideone.com/BJN98X
Per Thread Singleton
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
secret

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!