boost/asio/detail/concurrency_hint.hpp
// // detail/concurrency_hint.hpp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2022 Christopher M. Kohlhoff (chris at kohlhoff dot com) // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #ifndef BOOST_ASIO_DETAIL_CONCURRENCY_HINT_HPP #define BOOST_ASIO_DETAIL_CONCURRENCY_HINT_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/config.hpp> #include <boost/asio/detail/noncopyable.hpp> // The concurrency hint ID and mask are used to identify when a "well-known" // concurrency hint value has been passed to the io_context. #define BOOST_ASIO_CONCURRENCY_HINT_ID 0xA5100000u #define BOOST_ASIO_CONCURRENCY_HINT_ID_MASK 0xFFFF0000u // If set, this bit indicates that the scheduler should perform locking. #define BOOST_ASIO_CONCURRENCY_HINT_LOCKING_SCHEDULER 0x1u // If set, this bit indicates that the reactor should perform locking when // managing descriptor registrations. #define BOOST_ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_REGISTRATION 0x2u // If set, this bit indicates that the reactor should perform locking for I/O. #define BOOST_ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_IO 0x4u // Helper macro to determine if we have a special concurrency hint. #define BOOST_ASIO_CONCURRENCY_HINT_IS_SPECIAL(hint) \ ((static_cast<unsigned>(hint) \ & BOOST_ASIO_CONCURRENCY_HINT_ID_MASK) \ == BOOST_ASIO_CONCURRENCY_HINT_ID) // Helper macro to determine if locking is enabled for a given facility. #define BOOST_ASIO_CONCURRENCY_HINT_IS_LOCKING(facility, hint) \ (((static_cast<unsigned>(hint) \ & (BOOST_ASIO_CONCURRENCY_HINT_ID_MASK \ | BOOST_ASIO_CONCURRENCY_HINT_LOCKING_ ## facility)) \ ^ BOOST_ASIO_CONCURRENCY_HINT_ID) != 0) // This special concurrency hint disables locking in both the scheduler and // reactor I/O. This hint has the following restrictions: // // - Care must be taken to ensure that all operations on the io_context and any // of its associated I/O objects (such as sockets and timers) occur in only // one thread at a time. // // - Asynchronous resolve operations fail with operation_not_supported. // // - If a signal_set is used with the io_context, signal_set objects cannot be // used with any other io_context in the program. #define BOOST_ASIO_CONCURRENCY_HINT_UNSAFE \ static_cast<int>(BOOST_ASIO_CONCURRENCY_HINT_ID) // This special concurrency hint disables locking in the reactor I/O. This hint // has the following restrictions: // // - Care must be taken to ensure that run functions on the io_context, and all // operations on the io_context's associated I/O objects (such as sockets and // timers), occur in only one thread at a time. #define BOOST_ASIO_CONCURRENCY_HINT_UNSAFE_IO \ static_cast<int>(BOOST_ASIO_CONCURRENCY_HINT_ID \ | BOOST_ASIO_CONCURRENCY_HINT_LOCKING_SCHEDULER \ | BOOST_ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_REGISTRATION) // The special concurrency hint provides full thread safety. #define BOOST_ASIO_CONCURRENCY_HINT_SAFE \ static_cast<int>(BOOST_ASIO_CONCURRENCY_HINT_ID \ | BOOST_ASIO_CONCURRENCY_HINT_LOCKING_SCHEDULER \ | BOOST_ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_REGISTRATION \ | BOOST_ASIO_CONCURRENCY_HINT_LOCKING_REACTOR_IO) // This #define may be overridden at compile time to specify a program-wide // default concurrency hint, used by the zero-argument io_context constructor. #if !defined(BOOST_ASIO_CONCURRENCY_HINT_DEFAULT) # define BOOST_ASIO_CONCURRENCY_HINT_DEFAULT -1 #endif // !defined(BOOST_ASIO_CONCURRENCY_HINT_DEFAULT) // This #define may be overridden at compile time to specify a program-wide // concurrency hint, used by the one-argument io_context constructor when // passed a value of 1. #if !defined(BOOST_ASIO_CONCURRENCY_HINT_1) # define BOOST_ASIO_CONCURRENCY_HINT_1 1 #endif // !defined(BOOST_ASIO_CONCURRENCY_HINT_DEFAULT) #endif // BOOST_ASIO_DETAIL_CONCURRENCY_HINT_HPP