1 // 2 // detail/thread_group.hpp 3 // ~~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2021 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 #include <boost/asio/detail/push_options.hpp> 23 24 namespace boost { 25 namespace asio { 26 namespace detail { 27 28 class thread_group 29 { 30 public: 31 // Constructor initialises an empty thread group. thread_group()32 thread_group() 33 : first_(0) 34 { 35 } 36 37 // Destructor joins any remaining threads in the group. ~thread_group()38 ~thread_group() 39 { 40 join(); 41 } 42 43 // Create a new thread in the group. 44 template <typename Function> create_thread(Function f)45 void create_thread(Function f) 46 { 47 first_ = new item(f, first_); 48 } 49 50 // Create new threads in the group. 51 template <typename Function> create_threads(Function f,std::size_t num_threads)52 void create_threads(Function f, std::size_t num_threads) 53 { 54 for (std::size_t i = 0; i < num_threads; ++i) 55 create_thread(f); 56 } 57 58 // Wait for all threads in the group to exit. join()59 void join() 60 { 61 while (first_) 62 { 63 first_->thread_.join(); 64 item* tmp = first_; 65 first_ = first_->next_; 66 delete tmp; 67 } 68 } 69 70 // Test whether the group is empty. empty() const71 bool empty() const 72 { 73 return first_ == 0; 74 } 75 76 private: 77 // Structure used to track a single thread in the group. 78 struct item 79 { 80 template <typename Function> itemboost::asio::detail::thread_group::item81 explicit item(Function f, item* next) 82 : thread_(f), 83 next_(next) 84 { 85 } 86 87 boost::asio::detail::thread thread_; 88 item* next_; 89 }; 90 91 // The first thread in the group. 92 item* first_; 93 }; 94 95 } // namespace detail 96 } // namespace asio 97 } // namespace boost 98 99 #include <boost/asio/detail/pop_options.hpp> 100 101 #endif // BOOST_ASIO_DETAIL_THREAD_GROUP_HPP 102