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  1. #include <iostream>
  2. #include <stdexcept>
  3. #include <vector>
  4. #include <memory>
  5. #include <chrono>
  6. #include <thread>
  7. #include <mutex>
  8. #include <queue>
  9. #include <condition_variable>
  10. #include <atomic>
  11. #include <utility>
  12. #include <cassert>
  13. using namespace std;
  14. using namespace std::chrono;
  15.  
  16.  
  17. #define CONCURRENT
  18.  
  19. #define N_GRAPHICS		(1 * 1000 * 1000)
  20. #define N_THREADS		8
  21.  
  22.  
  23.  
  24. struct Graphic;
  25.  
  26. static vector<size_t> indexes;
  27. static vector<unique_ptr<Graphic>> graphics;
  28.  
  29. static queue<pair<Graphic*, size_t>> q;
  30. static mutex m;
  31. static atomic<size_t> n_elements;
  32.  
  33.  
  34. struct Graphic
  35. {
  36. 	Graphic()
  37. 		: status(false)
  38. 	{
  39. 	}
  40.  
  41.  
  42. 	bool parse()
  43. 	{
  44. 		// waste time
  45. 		try
  46. 		{
  47. 			throw runtime_error("");
  48. 		} 
  49. 		catch (runtime_error)
  50. 		{
  51. 		}
  52.  
  53. 		status = true;
  54. 		//return false;
  55. 		return true;
  56. 	}
  57.  
  58.  
  59. 	bool status;
  60. };
  61.  
  62.  
  63.  
  64.  
  65. static void producer()
  66. {
  67. 	for (size_t i = 0; i < N_GRAPHICS; i++)
  68. 	{
  69. 		auto g = new Graphic();
  70.  
  71. #ifdef CONCURRENT
  72. 		graphics.emplace_back(g);
  73. 		q.emplace(make_pair(g, i));
  74. #else
  75. 		if (g->parse())
  76. 			graphics.emplace_back(g);
  77. 		else
  78. 			delete g;
  79. #endif
  80. 	}
  81.  
  82. 	n_elements = graphics.size();
  83. }
  84.  
  85.  
  86.  
  87. static void consumer()
  88. {
  89. 	pair<Graphic*, size_t> item;
  90.  
  91. 	while (true)
  92. 	{
  93. 		{
  94. 			std::unique_lock<std::mutex> lk(m);
  95.  
  96. 			if (n_elements == 0)
  97. 				return;
  98.  
  99. 			n_elements--;
  100. 			item = q.front();
  101. 			q.pop();
  102. 		}
  103.  
  104. 		if (!item.first->parse())
  105. 		{
  106. 			assert(graphics[item.second].get() == item.first);
  107. 			delete item.first;
  108. 			graphics[item.second] = nullptr;
  109. 		}
  110. 	}
  111. }
  112.  
  113.  
  114.  
  115.  
  116. int main()
  117. {
  118. 	auto start = system_clock::now();
  119.  
  120. 	producer();
  121.  
  122. #ifdef CONCURRENT
  123.  
  124. 	vector<thread> threads;
  125.  
  126. 	for (auto i = 0; i < N_THREADS; i++)
  127. 		threads.emplace_back(consumer);
  128.  
  129. #endif
  130.  
  131. 	for (size_t i = 0; i < graphics.size(); i++)
  132. 		indexes.push_back(i);
  133.  
  134. #ifdef CONCURRENT
  135.  
  136. 	for (auto& t : threads)
  137. 		t.join();
  138.  
  139. #endif
  140.  
  141. 	auto duration = duration_cast<milliseconds>(system_clock::now() - start);
  142. 	cout << "Elapsed: " << duration.count() << endl;
  143.  
  144. 	for (size_t i = 0; i < graphics.size(); i++)
  145. 	{
  146. 		if (!graphics[i]->status)
  147. 		{
  148. 			cerr << "Assertion failed! (" << i << ")" << endl;
  149. 			break;
  150. 		}
  151. 	}
  152.  
  153. 	cin.get();
  154. 	return 0;
  155. }
Compilation error #stdin compilation error #stdout 0s 0KB
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stdin
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Standard input is empty
compilation info 
/home/UgUvEh/ccsoRNh0.o: In function `void std::vector<std::thread, std::allocator<std::thread> >::_M_emplace_back_aux<void (&)()>(void (&)())':
prog.cpp:(.text._ZNSt6vectorISt6threadSaIS0_EE19_M_emplace_back_auxIIRFvvEEEEvDpOT_[_ZNSt6vectorISt6threadSaIS0_EE19_M_emplace_back_auxIIRFvvEEEEvDpOT_]+0x60): undefined reference to `pthread_create'
/home/UgUvEh/ccsoRNh0.o: In function `main':
prog.cpp:(.text.startup+0x14e): undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
stdout
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Standard output is empty
https://ideone.com/p341du
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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