1 // 2 // detail/thread_group.hpp 3 // ~~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com) 6 // 7 // Distributed under the Boost Software License, Version 1.0. (See accompanying 8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 9 // 10 11 #ifndef BOOST_ASIO_DETAIL_THREAD_GROUP_HPP 12 #define BOOST_ASIO_DETAIL_THREAD_GROUP_HPP 13 14 #if defined(_MSC_VER) && (_MSC_VER >= 1200) 15 # pragma once 16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) 17 18 #include <boost/asio/detail/config.hpp> 19 #include <boost/asio/detail/scoped_ptr.hpp> 20 #include <boost/asio/detail/thread.hpp> 21 22 namespace boost { 23 namespace asio { 24 namespace detail { 25 26 class thread_group 27 { 28 public: 29 // Constructor initialises an empty thread group. thread_group()30 thread_group() 31 : first_(0) 32 { 33 } 34 35 // Destructor joins any remaining threads in the group. ~thread_group()36 ~thread_group() 37 { 38 join(); 39 } 40 41 // Create a new thread in the group. 42 template <typename Function> create_thread(Function f)43 void create_thread(Function f) 44 { 45 first_ = new item(f, first_); 46 } 47 48 // Create new threads in the group. 49 template <typename Function> create_threads(Function f,std::size_t num_threads)50 void create_threads(Function f, std::size_t num_threads) 51 { 52 for (std::size_t i = 0; i < num_threads; ++i) 53 create_thread(f); 54 } 55 56 // Wait for all threads in the group to exit. join()57 void join() 58 { 59 while (first_) 60 { 61 first_->thread_.join(); 62 item* tmp = first_; 63 first_ = first_->next_; 64 delete tmp; 65 } 66 } 67 68 // Test whether the group is empty. empty() const69 bool empty() const 70 { 71 return first_ == 0; 72 } 73 74 private: 75 // Structure used to track a single thread in the group. 76 struct item 77 { 78 template <typename Function> itemboost::asio::detail::thread_group::item79 explicit item(Function f, item* next) 80 : thread_(f), 81 next_(next) 82 { 83 } 84 85 boost::asio::detail::thread thread_; 86 item* next_; 87 }; 88 89 // The first thread in the group. 90 item* first_; 91 }; 92 93 } // namespace detail 94 } // namespace asio 95 } // namespace boost 96 97 #endif // BOOST_ASIO_DETAIL_THREAD_GROUP_HPP 98