concurrent_queue.cpp

Shows how to use xtd::collections::concurrent::concurrent_queue class.

#include <xtd/xtd>
 
class example {
public:
  static auto main() {
    auto items = collections::concurrent::concurrent_queue<int> {};
    
    parallel::invoke(array<action<>> {10_z, delegate_ {
      for (auto i : views::range(1, 10)) {
        items.enqueue(as<int>(task<>::current_id()) * 10 + i);
        thread::sleep(10_ms);
      }
    }});
    
    auto results = items.distinct().order().to_array();
    console::write_line("After enqueueing");
    console::write_line("  items.length = {}", results.length());
    console::write_line("  items = {}", results.to_array());
    
    parallel::invoke(array<action<>> {10, delegate_ {
      for ([[maybe_unused]] auto _ : views::range(1, 5)) {
        auto value = 0;
        items.try_dequeue(value);
        thread::sleep(10_ms);
      }
    }});
    
    results = items.distinct().order().to_array();
    console::write_line("After dequeueing");
    console::write_line("  items.length = {}", results.length());
    console::write_line("  items = {}", results.to_array());
  }
};
 
startup_(example::main);
 
// This code produces the following output :
//
// After enqueueing
//   items.length = 100
//   items = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100]
// After dequeueing
//   items.length = 50
//   items = [6, 7, 8, 9, 10, 16, 17, 18, 19, 20, 26, 27, 28, 29, 30, 36, 37, 38, 39, 40, 46, 47, 48, 49, 50, 56, 57, 58, 59, 60, 66, 67, 68, 69, 70, 76, 77, 78, 79, 80, 86, 87, 88, 89, 90, 96, 97, 98, 99, 100]