explorer.md

• print_size: print file size
• print_permitions: print file permitions
• print_modified_date: print modified date

using f1 = print_size;
using f2 = print_permitions;
using f3 = print_modified_date;

bool print_info(const path& p) {
  bool is_ok = true;
  is_ok &= f1(p);
  is_ok &= f2(p);
  is_ok &= f3(p);
  return is_ok;
}

using f = print_info;

$ ./explorer p1 p2 p3 p4 p5 p6

int main(int argc, char* argv[]) {
  
  scheduler_t scheduler;
  std::map<path, std::future<bool>> results;

  for (int i = 1; i < argc; ++i) { 
	path p = argv[i];
    auto task = std::package_task<bool()>{ std::bind(f, p) }; 
	auto result = task.get_future();
	sheduler.add(task);
	results.emplace(p, std::move(result));
  }

  scheduler.run(); // run in a new thred

  for(auto & p : results) {
    auto& result = results[p];
    auto is_ok = result.get();
    if (! is_ok) {
      std::cerr << "<your error message>:" << p << std::endl;
    }
  } 
}

   task1     task2     task3     task4     task5     task6
 +-------+ +-------+ +-------+ +-------+ +-------+ +-------+ 
 | f{p1} | | f{p2} | | f{p3} | | f{p4} | | f{p5} | | f{p6} | 
 +-------+ +-------+ +-------+ +-------+ +-------+ +-------+ 
     ^      
     |      	+-----------+ 
     +----------| scheduler | 	
                +-----------+ 

main    run                                                   
 -----------------------------------------------------> 
          \
           \
            \--------------------------------------------->
                 \                   \
                  \   task1           \   task5
                   \------------>{r1}  \------------>{r5}
                    \                   \
                     \   task2           \   task6
                      \------------>{r2}  \------------>{r6}
                       \
                        \   task3
                         \------------>{r3}
                          \             
                           \   task4     
                            \------------>{r4}

std::thread::hardware_concurrency() == 4;