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- //
- // basic_signal_set.hpp
- // ~~~~~~~~~~~~~~~~~~~~
- //
- // Copyright (c) 2003-2015 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 ASIO_BASIC_SIGNAL_SET_HPP
- #define ASIO_BASIC_SIGNAL_SET_HPP
-
- #if defined(_MSC_VER) && (_MSC_VER >= 1200)
- # pragma once
- #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
-
- #include "asio/detail/config.hpp"
-
- #include "asio/basic_io_object.hpp"
- #include "asio/detail/handler_type_requirements.hpp"
- #include "asio/detail/throw_error.hpp"
- #include "asio/error.hpp"
- #include "asio/signal_set_service.hpp"
-
- #include "asio/detail/push_options.hpp"
-
- namespace asio {
-
- /// Provides signal functionality.
- /**
- * The basic_signal_set class template provides the ability to perform an
- * asynchronous wait for one or more signals to occur.
- *
- * Most applications will use the asio::signal_set typedef.
- *
- * @par Thread Safety
- * @e Distinct @e objects: Safe.@n
- * @e Shared @e objects: Unsafe.
- *
- * @par Example
- * Performing an asynchronous wait:
- * @code
- * void handler(
- * const asio::error_code& error,
- * int signal_number)
- * {
- * if (!error)
- * {
- * // A signal occurred.
- * }
- * }
- *
- * ...
- *
- * // Construct a signal set registered for process termination.
- * asio::signal_set signals(io_context, SIGINT, SIGTERM);
- *
- * // Start an asynchronous wait for one of the signals to occur.
- * signals.async_wait(handler);
- * @endcode
- *
- * @par Queueing of signal notifications
- *
- * If a signal is registered with a signal_set, and the signal occurs when
- * there are no waiting handlers, then the signal notification is queued. The
- * next async_wait operation on that signal_set will dequeue the notification.
- * If multiple notifications are queued, subsequent async_wait operations
- * dequeue them one at a time. Signal notifications are dequeued in order of
- * ascending signal number.
- *
- * If a signal number is removed from a signal_set (using the @c remove or @c
- * erase member functions) then any queued notifications for that signal are
- * discarded.
- *
- * @par Multiple registration of signals
- *
- * The same signal number may be registered with different signal_set objects.
- * When the signal occurs, one handler is called for each signal_set object.
- *
- * Note that multiple registration only works for signals that are registered
- * using Asio. The application must not also register a signal handler using
- * functions such as @c signal() or @c sigaction().
- *
- * @par Signal masking on POSIX platforms
- *
- * POSIX allows signals to be blocked using functions such as @c sigprocmask()
- * and @c pthread_sigmask(). For signals to be delivered, programs must ensure
- * that any signals registered using signal_set objects are unblocked in at
- * least one thread.
- */
- template <typename SignalSetService = signal_set_service>
- class basic_signal_set
- : public basic_io_object<SignalSetService>
- {
- public:
- /// Construct a signal set without adding any signals.
- /**
- * This constructor creates a signal set without registering for any signals.
- *
- * @param io_context The io_context object that the signal set will use to
- * dispatch handlers for any asynchronous operations performed on the set.
- */
- explicit basic_signal_set(asio::io_context& io_context)
- : basic_io_object<SignalSetService>(io_context)
- {
- }
-
- /// Construct a signal set and add one signal.
- /**
- * This constructor creates a signal set and registers for one signal.
- *
- * @param io_context The io_context object that the signal set will use to
- * dispatch handlers for any asynchronous operations performed on the set.
- *
- * @param signal_number_1 The signal number to be added.
- *
- * @note This constructor is equivalent to performing:
- * @code asio::signal_set signals(io_context);
- * signals.add(signal_number_1); @endcode
- */
- basic_signal_set(asio::io_context& io_context, int signal_number_1)
- : basic_io_object<SignalSetService>(io_context)
- {
- asio::error_code ec;
- this->get_service().add(this->get_implementation(), signal_number_1, ec);
- asio::detail::throw_error(ec, "add");
- }
-
- /// Construct a signal set and add two signals.
- /**
- * This constructor creates a signal set and registers for two signals.
- *
- * @param io_context The io_context object that the signal set will use to
- * dispatch handlers for any asynchronous operations performed on the set.
- *
- * @param signal_number_1 The first signal number to be added.
- *
- * @param signal_number_2 The second signal number to be added.
- *
- * @note This constructor is equivalent to performing:
- * @code asio::signal_set signals(io_context);
- * signals.add(signal_number_1);
- * signals.add(signal_number_2); @endcode
- */
- basic_signal_set(asio::io_context& io_context, int signal_number_1,
- int signal_number_2)
- : basic_io_object<SignalSetService>(io_context)
- {
- asio::error_code ec;
- this->get_service().add(this->get_implementation(), signal_number_1, ec);
- asio::detail::throw_error(ec, "add");
- this->get_service().add(this->get_implementation(), signal_number_2, ec);
- asio::detail::throw_error(ec, "add");
- }
-
- /// Construct a signal set and add three signals.
- /**
- * This constructor creates a signal set and registers for three signals.
- *
- * @param io_context The io_context object that the signal set will use to
- * dispatch handlers for any asynchronous operations performed on the set.
- *
- * @param signal_number_1 The first signal number to be added.
- *
- * @param signal_number_2 The second signal number to be added.
- *
- * @param signal_number_3 The third signal number to be added.
- *
- * @note This constructor is equivalent to performing:
- * @code asio::signal_set signals(io_context);
- * signals.add(signal_number_1);
- * signals.add(signal_number_2);
- * signals.add(signal_number_3); @endcode
- */
- basic_signal_set(asio::io_context& io_context, int signal_number_1,
- int signal_number_2, int signal_number_3)
- : basic_io_object<SignalSetService>(io_context)
- {
- asio::error_code ec;
- this->get_service().add(this->get_implementation(), signal_number_1, ec);
- asio::detail::throw_error(ec, "add");
- this->get_service().add(this->get_implementation(), signal_number_2, ec);
- asio::detail::throw_error(ec, "add");
- this->get_service().add(this->get_implementation(), signal_number_3, ec);
- asio::detail::throw_error(ec, "add");
- }
-
- /// Add a signal to a signal_set.
- /**
- * This function adds the specified signal to the set. It has no effect if the
- * signal is already in the set.
- *
- * @param signal_number The signal to be added to the set.
- *
- * @throws asio::system_error Thrown on failure.
- */
- void add(int signal_number)
- {
- asio::error_code ec;
- this->get_service().add(this->get_implementation(), signal_number, ec);
- asio::detail::throw_error(ec, "add");
- }
-
- /// Add a signal to a signal_set.
- /**
- * This function adds the specified signal to the set. It has no effect if the
- * signal is already in the set.
- *
- * @param signal_number The signal to be added to the set.
- *
- * @param ec Set to indicate what error occurred, if any.
- */
- asio::error_code add(int signal_number,
- asio::error_code& ec)
- {
- return this->get_service().add(
- this->get_implementation(), signal_number, ec);
- }
-
- /// Remove a signal from a signal_set.
- /**
- * This function removes the specified signal from the set. It has no effect
- * if the signal is not in the set.
- *
- * @param signal_number The signal to be removed from the set.
- *
- * @throws asio::system_error Thrown on failure.
- *
- * @note Removes any notifications that have been queued for the specified
- * signal number.
- */
- void remove(int signal_number)
- {
- asio::error_code ec;
- this->get_service().remove(this->get_implementation(), signal_number, ec);
- asio::detail::throw_error(ec, "remove");
- }
-
- /// Remove a signal from a signal_set.
- /**
- * This function removes the specified signal from the set. It has no effect
- * if the signal is not in the set.
- *
- * @param signal_number The signal to be removed from the set.
- *
- * @param ec Set to indicate what error occurred, if any.
- *
- * @note Removes any notifications that have been queued for the specified
- * signal number.
- */
- asio::error_code remove(int signal_number,
- asio::error_code& ec)
- {
- return this->get_service().remove(
- this->get_implementation(), signal_number, ec);
- }
-
- /// Remove all signals from a signal_set.
- /**
- * This function removes all signals from the set. It has no effect if the set
- * is already empty.
- *
- * @throws asio::system_error Thrown on failure.
- *
- * @note Removes all queued notifications.
- */
- void clear()
- {
- asio::error_code ec;
- this->get_service().clear(this->get_implementation(), ec);
- asio::detail::throw_error(ec, "clear");
- }
-
- /// Remove all signals from a signal_set.
- /**
- * This function removes all signals from the set. It has no effect if the set
- * is already empty.
- *
- * @param ec Set to indicate what error occurred, if any.
- *
- * @note Removes all queued notifications.
- */
- asio::error_code clear(asio::error_code& ec)
- {
- return this->get_service().clear(this->get_implementation(), ec);
- }
-
- /// Cancel all operations associated with the signal set.
- /**
- * This function forces the completion of any pending asynchronous wait
- * operations against the signal set. The handler for each cancelled
- * operation will be invoked with the asio::error::operation_aborted
- * error code.
- *
- * Cancellation does not alter the set of registered signals.
- *
- * @throws asio::system_error Thrown on failure.
- *
- * @note If a registered signal occurred before cancel() is called, then the
- * handlers for asynchronous wait operations will:
- *
- * @li have already been invoked; or
- *
- * @li have been queued for invocation in the near future.
- *
- * These handlers can no longer be cancelled, and therefore are passed an
- * error code that indicates the successful completion of the wait operation.
- */
- void cancel()
- {
- asio::error_code ec;
- this->get_service().cancel(this->get_implementation(), ec);
- asio::detail::throw_error(ec, "cancel");
- }
-
- /// Cancel all operations associated with the signal set.
- /**
- * This function forces the completion of any pending asynchronous wait
- * operations against the signal set. The handler for each cancelled
- * operation will be invoked with the asio::error::operation_aborted
- * error code.
- *
- * Cancellation does not alter the set of registered signals.
- *
- * @param ec Set to indicate what error occurred, if any.
- *
- * @note If a registered signal occurred before cancel() is called, then the
- * handlers for asynchronous wait operations will:
- *
- * @li have already been invoked; or
- *
- * @li have been queued for invocation in the near future.
- *
- * These handlers can no longer be cancelled, and therefore are passed an
- * error code that indicates the successful completion of the wait operation.
- */
- asio::error_code cancel(asio::error_code& ec)
- {
- return this->get_service().cancel(this->get_implementation(), ec);
- }
-
- /// Start an asynchronous operation to wait for a signal to be delivered.
- /**
- * This function may be used to initiate an asynchronous wait against the
- * signal set. It always returns immediately.
- *
- * For each call to async_wait(), the supplied handler will be called exactly
- * once. The handler will be called when:
- *
- * @li One of the registered signals in the signal set occurs; or
- *
- * @li The signal set was cancelled, in which case the handler is passed the
- * error code asio::error::operation_aborted.
- *
- * @param handler The handler to be called when the signal occurs. Copies
- * will be made of the handler as required. The function signature of the
- * handler must be:
- * @code void handler(
- * const asio::error_code& error, // Result of operation.
- * int signal_number // Indicates which signal occurred.
- * ); @endcode
- * Regardless of whether the asynchronous operation completes immediately or
- * not, the handler will not be invoked from within this function. Invocation
- * of the handler will be performed in a manner equivalent to using
- * asio::io_context::post().
- */
- template <typename SignalHandler>
- ASIO_INITFN_RESULT_TYPE(SignalHandler,
- void (asio::error_code, int))
- async_wait(ASIO_MOVE_ARG(SignalHandler) handler)
- {
- // If you get an error on the following line it means that your handler does
- // not meet the documented type requirements for a SignalHandler.
- ASIO_SIGNAL_HANDLER_CHECK(SignalHandler, handler) type_check;
-
- return this->get_service().async_wait(this->get_implementation(),
- ASIO_MOVE_CAST(SignalHandler)(handler));
- }
- };
-
- } // namespace asio
-
- #include "asio/detail/pop_options.hpp"
-
- #endif // ASIO_BASIC_SIGNAL_SET_HPP
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