// // pipe_select_interrupter.hpp // ~~~~~~~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2010 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_PIPE_SELECT_INTERRUPTER_HPP #define BOOST_ASIO_DETAIL_PIPE_SELECT_INTERRUPTER_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/push_options.hpp> #include <boost/asio/detail/push_options.hpp> #include <boost/config.hpp> #include <boost/throw_exception.hpp> #include <boost/system/system_error.hpp> #include <boost/asio/detail/pop_options.hpp> #if !defined(BOOST_WINDOWS) && !defined(__CYGWIN__) #include <boost/asio/detail/push_options.hpp> #include <fcntl.h> #include <boost/asio/detail/pop_options.hpp> #include <boost/asio/error.hpp> #include <boost/asio/detail/socket_types.hpp> namespace boost { namespace asio { namespace detail { class pipe_select_interrupter { public: // Constructor. pipe_select_interrupter() { int pipe_fds[2]; if (pipe(pipe_fds) == 0) { read_descriptor_ = pipe_fds[0]; ::fcntl(read_descriptor_, F_SETFL, O_NONBLOCK); write_descriptor_ = pipe_fds[1]; ::fcntl(write_descriptor_, F_SETFL, O_NONBLOCK); } else { boost::system::error_code ec(errno, boost::asio::error::get_system_category()); boost::system::system_error e(ec, "pipe_select_interrupter"); boost::throw_exception(e); } } // Destructor. ~pipe_select_interrupter() { if (read_descriptor_ != -1) ::close(read_descriptor_); if (write_descriptor_ != -1) ::close(write_descriptor_); } // Interrupt the select call. void interrupt() { char byte = 0; int result = ::write(write_descriptor_, &byte, 1); (void)result; } // Reset the select interrupt. Returns true if the call was interrupted. bool reset() { for (;;) { char data[1024]; int bytes_read = ::read(read_descriptor_, data, sizeof(data)); if (bytes_read < 0 && errno == EINTR) continue; bool was_interrupted = (bytes_read > 0); while (bytes_read == sizeof(data)) bytes_read = ::read(read_descriptor_, data, sizeof(data)); return was_interrupted; } } // Get the read descriptor to be passed to select. int read_descriptor() const { return read_descriptor_; } private: // The read end of a connection used to interrupt the select call. This file // descriptor is passed to select such that when it is time to stop, a single // byte will be written on the other end of the connection and this // descriptor will become readable. int read_descriptor_; // The write end of a connection used to interrupt the select call. A single // byte may be written to this to wake up the select which is waiting for the // other end to become readable. int write_descriptor_; }; } // namespace detail } // namespace asio } // namespace boost #endif // !defined(BOOST_WINDOWS) && !defined(__CYGWIN__) #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_DETAIL_PIPE_SELECT_INTERRUPTER_HPP