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include/asio/basic_signal_set.hpp
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653
include/asio/basic_signal_set.hpp
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//
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// basic_signal_set.hpp
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// ~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_BASIC_SIGNAL_SET_HPP
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#define ASIO_BASIC_SIGNAL_SET_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/config.hpp"
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#include "asio/any_io_executor.hpp"
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#include "asio/async_result.hpp"
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#include "asio/detail/handler_type_requirements.hpp"
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#include "asio/detail/io_object_impl.hpp"
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#include "asio/detail/non_const_lvalue.hpp"
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#include "asio/detail/signal_set_service.hpp"
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#include "asio/detail/throw_error.hpp"
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#include "asio/detail/type_traits.hpp"
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#include "asio/error.hpp"
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#include "asio/execution_context.hpp"
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#include "asio/signal_set_base.hpp"
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#include "asio/detail/push_options.hpp"
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namespace asio {
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/// Provides signal functionality.
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/**
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* The basic_signal_set class provides the ability to perform an asynchronous
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* wait for one or more signals to occur.
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*
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* @par Thread Safety
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* @e Distinct @e objects: Safe.@n
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* @e Shared @e objects: Unsafe.
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*
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* @par Example
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* Performing an asynchronous wait:
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* @code
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* void handler(
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* const asio::error_code& error,
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* int signal_number)
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* {
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* if (!error)
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* {
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* // A signal occurred.
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* }
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* }
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*
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* ...
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*
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* // Construct a signal set registered for process termination.
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* asio::signal_set signals(my_context, SIGINT, SIGTERM);
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*
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* // Start an asynchronous wait for one of the signals to occur.
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* signals.async_wait(handler);
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* @endcode
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*
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* @par Queueing of signal notifications
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*
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* If a signal is registered with a signal_set, and the signal occurs when
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* there are no waiting handlers, then the signal notification is queued. The
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* next async_wait operation on that signal_set will dequeue the notification.
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* If multiple notifications are queued, subsequent async_wait operations
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* dequeue them one at a time. Signal notifications are dequeued in order of
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* ascending signal number.
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*
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* If a signal number is removed from a signal_set (using the @c remove or @c
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* erase member functions) then any queued notifications for that signal are
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* discarded.
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*
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* @par Multiple registration of signals
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*
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* The same signal number may be registered with different signal_set objects.
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* When the signal occurs, one handler is called for each signal_set object.
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*
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* Note that multiple registration only works for signals that are registered
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* using Asio. The application must not also register a signal handler using
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* functions such as @c signal() or @c sigaction().
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*
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* @par Signal masking on POSIX platforms
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*
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* POSIX allows signals to be blocked using functions such as @c sigprocmask()
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* and @c pthread_sigmask(). For signals to be delivered, programs must ensure
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* that any signals registered using signal_set objects are unblocked in at
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* least one thread.
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*/
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template <typename Executor = any_io_executor>
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class basic_signal_set : public signal_set_base
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{
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private:
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class initiate_async_wait;
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public:
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/// The type of the executor associated with the object.
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typedef Executor executor_type;
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/// Rebinds the signal set type to another executor.
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template <typename Executor1>
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struct rebind_executor
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{
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/// The signal set type when rebound to the specified executor.
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typedef basic_signal_set<Executor1> other;
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};
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/// Construct a signal set without adding any signals.
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/**
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* This constructor creates a signal set without registering for any signals.
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*
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* @param ex The I/O executor that the signal set will use, by default, to
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* dispatch handlers for any asynchronous operations performed on the
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* signal set.
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*/
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explicit basic_signal_set(const executor_type& ex)
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: impl_(0, ex)
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{
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}
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/// Construct a signal set without adding any signals.
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/**
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* This constructor creates a signal set without registering for any signals.
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*
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* @param context An execution context which provides the I/O executor that
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* the signal set will use, by default, to dispatch handlers for any
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* asynchronous operations performed on the signal set.
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*/
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template <typename ExecutionContext>
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explicit basic_signal_set(ExecutionContext& context,
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constraint_t<
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is_convertible<ExecutionContext&, execution_context&>::value,
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defaulted_constraint
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> = defaulted_constraint())
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: impl_(0, 0, context)
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{
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}
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/// Construct a signal set and add one signal.
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/**
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* This constructor creates a signal set and registers for one signal.
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*
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* @param ex The I/O executor that the signal set will use, by default, to
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* dispatch handlers for any asynchronous operations performed on the
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* signal set.
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*
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* @param signal_number_1 The signal number to be added.
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*
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* @note This constructor is equivalent to performing:
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* @code asio::signal_set signals(ex);
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* signals.add(signal_number_1); @endcode
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*/
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basic_signal_set(const executor_type& ex, int signal_number_1)
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: impl_(0, ex)
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{
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asio::error_code ec;
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impl_.get_service().add(impl_.get_implementation(), signal_number_1, ec);
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asio::detail::throw_error(ec, "add");
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}
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/// Construct a signal set and add one signal.
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/**
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* This constructor creates a signal set and registers for one signal.
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*
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* @param context An execution context which provides the I/O executor that
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* the signal set will use, by default, to dispatch handlers for any
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* asynchronous operations performed on the signal set.
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*
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* @param signal_number_1 The signal number to be added.
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*
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* @note This constructor is equivalent to performing:
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* @code asio::signal_set signals(context);
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* signals.add(signal_number_1); @endcode
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*/
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template <typename ExecutionContext>
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basic_signal_set(ExecutionContext& context, int signal_number_1,
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constraint_t<
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is_convertible<ExecutionContext&, execution_context&>::value,
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defaulted_constraint
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> = defaulted_constraint())
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: impl_(0, 0, context)
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{
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asio::error_code ec;
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impl_.get_service().add(impl_.get_implementation(), signal_number_1, ec);
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asio::detail::throw_error(ec, "add");
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}
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/// Construct a signal set and add two signals.
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/**
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* This constructor creates a signal set and registers for two signals.
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*
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* @param ex The I/O executor that the signal set will use, by default, to
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* dispatch handlers for any asynchronous operations performed on the
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* signal set.
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*
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* @param signal_number_1 The first signal number to be added.
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*
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* @param signal_number_2 The second signal number to be added.
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*
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* @note This constructor is equivalent to performing:
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* @code asio::signal_set signals(ex);
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* signals.add(signal_number_1);
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* signals.add(signal_number_2); @endcode
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*/
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basic_signal_set(const executor_type& ex, int signal_number_1,
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int signal_number_2)
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: impl_(0, ex)
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{
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asio::error_code ec;
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impl_.get_service().add(impl_.get_implementation(), signal_number_1, ec);
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asio::detail::throw_error(ec, "add");
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impl_.get_service().add(impl_.get_implementation(), signal_number_2, ec);
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asio::detail::throw_error(ec, "add");
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}
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/// Construct a signal set and add two signals.
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/**
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* This constructor creates a signal set and registers for two signals.
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*
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* @param context An execution context which provides the I/O executor that
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* the signal set will use, by default, to dispatch handlers for any
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* asynchronous operations performed on the signal set.
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*
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* @param signal_number_1 The first signal number to be added.
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*
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* @param signal_number_2 The second signal number to be added.
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*
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* @note This constructor is equivalent to performing:
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* @code asio::signal_set signals(context);
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* signals.add(signal_number_1);
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* signals.add(signal_number_2); @endcode
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*/
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template <typename ExecutionContext>
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basic_signal_set(ExecutionContext& context, int signal_number_1,
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int signal_number_2,
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constraint_t<
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is_convertible<ExecutionContext&, execution_context&>::value,
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defaulted_constraint
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> = defaulted_constraint())
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: impl_(0, 0, context)
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{
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asio::error_code ec;
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impl_.get_service().add(impl_.get_implementation(), signal_number_1, ec);
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asio::detail::throw_error(ec, "add");
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impl_.get_service().add(impl_.get_implementation(), signal_number_2, ec);
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asio::detail::throw_error(ec, "add");
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}
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/// Construct a signal set and add three signals.
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/**
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* This constructor creates a signal set and registers for three signals.
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*
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* @param ex The I/O executor that the signal set will use, by default, to
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* dispatch handlers for any asynchronous operations performed on the
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* signal set.
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*
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* @param signal_number_1 The first signal number to be added.
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*
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* @param signal_number_2 The second signal number to be added.
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*
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* @param signal_number_3 The third signal number to be added.
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*
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* @note This constructor is equivalent to performing:
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* @code asio::signal_set signals(ex);
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* signals.add(signal_number_1);
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* signals.add(signal_number_2);
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* signals.add(signal_number_3); @endcode
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*/
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basic_signal_set(const executor_type& ex, int signal_number_1,
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int signal_number_2, int signal_number_3)
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: impl_(0, ex)
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{
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asio::error_code ec;
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impl_.get_service().add(impl_.get_implementation(), signal_number_1, ec);
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asio::detail::throw_error(ec, "add");
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impl_.get_service().add(impl_.get_implementation(), signal_number_2, ec);
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asio::detail::throw_error(ec, "add");
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impl_.get_service().add(impl_.get_implementation(), signal_number_3, ec);
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asio::detail::throw_error(ec, "add");
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}
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/// Construct a signal set and add three signals.
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/**
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* This constructor creates a signal set and registers for three signals.
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*
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* @param context An execution context which provides the I/O executor that
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* the signal set will use, by default, to dispatch handlers for any
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* asynchronous operations performed on the signal set.
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*
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* @param signal_number_1 The first signal number to be added.
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*
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* @param signal_number_2 The second signal number to be added.
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*
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* @param signal_number_3 The third signal number to be added.
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*
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* @note This constructor is equivalent to performing:
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* @code asio::signal_set signals(context);
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* signals.add(signal_number_1);
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* signals.add(signal_number_2);
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* signals.add(signal_number_3); @endcode
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*/
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template <typename ExecutionContext>
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basic_signal_set(ExecutionContext& context, int signal_number_1,
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int signal_number_2, int signal_number_3,
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constraint_t<
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is_convertible<ExecutionContext&, execution_context&>::value,
|
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defaulted_constraint
|
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> = defaulted_constraint())
|
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: impl_(0, 0, context)
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{
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asio::error_code ec;
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impl_.get_service().add(impl_.get_implementation(), signal_number_1, ec);
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asio::detail::throw_error(ec, "add");
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impl_.get_service().add(impl_.get_implementation(), signal_number_2, ec);
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asio::detail::throw_error(ec, "add");
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impl_.get_service().add(impl_.get_implementation(), signal_number_3, ec);
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asio::detail::throw_error(ec, "add");
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}
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/// Destroys the signal set.
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/**
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* This function destroys the signal set, cancelling any outstanding
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* asynchronous wait operations associated with the signal set as if by
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* calling @c cancel.
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*/
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~basic_signal_set()
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{
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}
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/// Get the executor associated with the object.
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const executor_type& get_executor() noexcept
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{
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return impl_.get_executor();
|
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}
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/// Add a signal to a signal_set.
|
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/**
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* This function adds the specified signal to the set. It has no effect if the
|
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* signal is already in the set.
|
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*
|
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* @param signal_number The signal to be added to the set.
|
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*
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* @throws asio::system_error Thrown on failure.
|
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*/
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void add(int signal_number)
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{
|
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asio::error_code ec;
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impl_.get_service().add(impl_.get_implementation(), signal_number, ec);
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asio::detail::throw_error(ec, "add");
|
||||
}
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|
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/// Add a signal to a signal_set.
|
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/**
|
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* This function adds the specified signal to the set. It has no effect if the
|
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* signal is already in the set.
|
||||
*
|
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* @param signal_number The signal to be added to the set.
|
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*
|
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* @param ec Set to indicate what error occurred, if any.
|
||||
*/
|
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ASIO_SYNC_OP_VOID add(int signal_number,
|
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asio::error_code& ec)
|
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{
|
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impl_.get_service().add(impl_.get_implementation(), signal_number, ec);
|
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ASIO_SYNC_OP_VOID_RETURN(ec);
|
||||
}
|
||||
|
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/// Add a signal to a signal_set with the specified flags.
|
||||
/**
|
||||
* This function adds the specified signal to the set. It has no effect if the
|
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* signal is already in the set.
|
||||
*
|
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* Flags other than flags::dont_care require OS support for the @c sigaction
|
||||
* call, and this function will fail with @c error::operation_not_supported if
|
||||
* this is unavailable.
|
||||
*
|
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* The specified flags will conflict with a prior, active registration of the
|
||||
* same signal, if either specified a flags value other than flags::dont_care.
|
||||
* In this case, the @c add will fail with @c error::invalid_argument.
|
||||
*
|
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* @param signal_number The signal to be added to the set.
|
||||
*
|
||||
* @param f Flags to modify the behaviour of the specified signal.
|
||||
*
|
||||
* @throws asio::system_error Thrown on failure.
|
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*/
|
||||
void add(int signal_number, flags_t f)
|
||||
{
|
||||
asio::error_code ec;
|
||||
impl_.get_service().add(impl_.get_implementation(), signal_number, f, ec);
|
||||
asio::detail::throw_error(ec, "add");
|
||||
}
|
||||
|
||||
/// Add a signal to a signal_set with the specified flags.
|
||||
/**
|
||||
* This function adds the specified signal to the set. It has no effect if the
|
||||
* signal is already in the set.
|
||||
*
|
||||
* Flags other than flags::dont_care require OS support for the @c sigaction
|
||||
* call, and this function will fail with @c error::operation_not_supported if
|
||||
* this is unavailable.
|
||||
*
|
||||
* The specified flags will conflict with a prior, active registration of the
|
||||
* same signal, if either specified a flags value other than flags::dont_care.
|
||||
* In this case, the @c add will fail with @c error::invalid_argument.
|
||||
*
|
||||
* @param signal_number The signal to be added to the set.
|
||||
*
|
||||
* @param f Flags to modify the behaviour of the specified signal.
|
||||
*
|
||||
* @param ec Set to indicate what error occurred, if any.
|
||||
*/
|
||||
ASIO_SYNC_OP_VOID add(int signal_number, flags_t f,
|
||||
asio::error_code& ec)
|
||||
{
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||||
impl_.get_service().add(impl_.get_implementation(), signal_number, f, ec);
|
||||
ASIO_SYNC_OP_VOID_RETURN(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;
|
||||
impl_.get_service().remove(impl_.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_SYNC_OP_VOID remove(int signal_number,
|
||||
asio::error_code& ec)
|
||||
{
|
||||
impl_.get_service().remove(impl_.get_implementation(), signal_number, ec);
|
||||
ASIO_SYNC_OP_VOID_RETURN(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;
|
||||
impl_.get_service().clear(impl_.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_SYNC_OP_VOID clear(asio::error_code& ec)
|
||||
{
|
||||
impl_.get_service().clear(impl_.get_implementation(), ec);
|
||||
ASIO_SYNC_OP_VOID_RETURN(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;
|
||||
impl_.get_service().cancel(impl_.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_SYNC_OP_VOID cancel(asio::error_code& ec)
|
||||
{
|
||||
impl_.get_service().cancel(impl_.get_implementation(), ec);
|
||||
ASIO_SYNC_OP_VOID_RETURN(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 is an initiating function for an @ref
|
||||
* asynchronous_operation, and always returns immediately.
|
||||
*
|
||||
* For each call to async_wait(), the completion handler will be called
|
||||
* exactly once. The completion 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 token The @ref completion_token that will be used to produce a
|
||||
* completion handler, which will be called when the wait completes.
|
||||
* Potential completion tokens include @ref use_future, @ref use_awaitable,
|
||||
* @ref yield_context, or a function object with the correct completion
|
||||
* signature. The function signature of the completion 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 completion handler will not be invoked from within this function.
|
||||
* On immediate completion, invocation of the handler will be performed in a
|
||||
* manner equivalent to using asio::async_immediate().
|
||||
*
|
||||
* @par Completion Signature
|
||||
* @code void(asio::error_code, int) @endcode
|
||||
*
|
||||
* @par Per-Operation Cancellation
|
||||
* This asynchronous operation supports cancellation for the following
|
||||
* asio::cancellation_type values:
|
||||
*
|
||||
* @li @c cancellation_type::terminal
|
||||
*
|
||||
* @li @c cancellation_type::partial
|
||||
*
|
||||
* @li @c cancellation_type::total
|
||||
*
|
||||
* @note Unlike the POSIX function @c signal, @c async_wait executes its
|
||||
* completion handler as specified in the @ref async_op_requirements. This
|
||||
* means it places no async-signal safety restrictions on what work can be
|
||||
* performed in a completion handler.
|
||||
*/
|
||||
template <
|
||||
ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code, int))
|
||||
SignalToken = default_completion_token_t<executor_type>>
|
||||
auto async_wait(
|
||||
SignalToken&& token = default_completion_token_t<executor_type>())
|
||||
-> decltype(
|
||||
async_initiate<SignalToken, void (asio::error_code, int)>(
|
||||
declval<initiate_async_wait>(), token))
|
||||
{
|
||||
return async_initiate<SignalToken, void (asio::error_code, int)>(
|
||||
initiate_async_wait(this), token);
|
||||
}
|
||||
|
||||
private:
|
||||
// Disallow copying and assignment.
|
||||
basic_signal_set(const basic_signal_set&) = delete;
|
||||
basic_signal_set& operator=(const basic_signal_set&) = delete;
|
||||
|
||||
class initiate_async_wait
|
||||
{
|
||||
public:
|
||||
typedef Executor executor_type;
|
||||
|
||||
explicit initiate_async_wait(basic_signal_set* self)
|
||||
: self_(self)
|
||||
{
|
||||
}
|
||||
|
||||
const executor_type& get_executor() const noexcept
|
||||
{
|
||||
return self_->get_executor();
|
||||
}
|
||||
|
||||
template <typename SignalHandler>
|
||||
void operator()(SignalHandler&& handler) const
|
||||
{
|
||||
// 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;
|
||||
|
||||
detail::non_const_lvalue<SignalHandler> handler2(handler);
|
||||
self_->impl_.get_service().async_wait(
|
||||
self_->impl_.get_implementation(),
|
||||
handler2.value, self_->impl_.get_executor());
|
||||
}
|
||||
|
||||
private:
|
||||
basic_signal_set* self_;
|
||||
};
|
||||
|
||||
detail::io_object_impl<detail::signal_set_service, Executor> impl_;
|
||||
};
|
||||
|
||||
} // namespace asio
|
||||
|
||||
#include "asio/detail/pop_options.hpp"
|
||||
|
||||
#endif // ASIO_BASIC_SIGNAL_SET_HPP
|
||||
Reference in New Issue
Block a user