boost/asio/basic_signal_set.hpp
//
// 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 BOOST_ASIO_BASIC_SIGNAL_SET_HPP
#define BOOST_ASIO_BASIC_SIGNAL_SET_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/basic_io_object.hpp>
#include <boost/asio/detail/handler_type_requirements.hpp>
#include <boost/asio/detail/throw_error.hpp>
#include <boost/asio/error.hpp>
#include <boost/asio/signal_set_service.hpp>
#include <boost/asio/detail/push_options.hpp>
namespace boost {
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 boost::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 boost::system::error_code& error,
* int signal_number)
* {
* if (!error)
* {
* // A signal occurred.
* }
* }
*
* ...
*
* // Construct a signal set registered for process termination.
* boost::asio::signal_set signals(io_service, 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_service The io_service object that the signal set will use to
* dispatch handlers for any asynchronous operations performed on the set.
*/
explicit basic_signal_set(boost::asio::io_service& io_service)
: basic_io_object<SignalSetService>(io_service)
{
}
/// Construct a signal set and add one signal.
/**
* This constructor creates a signal set and registers for one signal.
*
* @param io_service The io_service 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 boost::asio::signal_set signals(io_service);
* signals.add(signal_number_1); @endcode
*/
basic_signal_set(boost::asio::io_service& io_service, int signal_number_1)
: basic_io_object<SignalSetService>(io_service)
{
boost::system::error_code ec;
this->service.add(this->implementation, signal_number_1, ec);
boost::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_service The io_service 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 boost::asio::signal_set signals(io_service);
* signals.add(signal_number_1);
* signals.add(signal_number_2); @endcode
*/
basic_signal_set(boost::asio::io_service& io_service, int signal_number_1,
int signal_number_2)
: basic_io_object<SignalSetService>(io_service)
{
boost::system::error_code ec;
this->service.add(this->implementation, signal_number_1, ec);
boost::asio::detail::throw_error(ec, "add");
this->service.add(this->implementation, signal_number_2, ec);
boost::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_service The io_service 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 boost::asio::signal_set signals(io_service);
* signals.add(signal_number_1);
* signals.add(signal_number_2);
* signals.add(signal_number_3); @endcode
*/
basic_signal_set(boost::asio::io_service& io_service, int signal_number_1,
int signal_number_2, int signal_number_3)
: basic_io_object<SignalSetService>(io_service)
{
boost::system::error_code ec;
this->service.add(this->implementation, signal_number_1, ec);
boost::asio::detail::throw_error(ec, "add");
this->service.add(this->implementation, signal_number_2, ec);
boost::asio::detail::throw_error(ec, "add");
this->service.add(this->implementation, signal_number_3, ec);
boost::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 boost::system::system_error Thrown on failure.
*/
void add(int signal_number)
{
boost::system::error_code ec;
this->service.add(this->implementation, signal_number, ec);
boost::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.
*/
boost::system::error_code add(int signal_number,
boost::system::error_code& ec)
{
return this->service.add(this->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 boost::system::system_error Thrown on failure.
*
* @note Removes any notifications that have been queued for the specified
* signal number.
*/
void remove(int signal_number)
{
boost::system::error_code ec;
this->service.remove(this->implementation, signal_number, ec);
boost::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.
*/
boost::system::error_code remove(int signal_number,
boost::system::error_code& ec)
{
return this->service.remove(this->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 boost::system::system_error Thrown on failure.
*
* @note Removes all queued notifications.
*/
void clear()
{
boost::system::error_code ec;
this->service.clear(this->implementation, ec);
boost::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.
*/
boost::system::error_code clear(boost::system::error_code& ec)
{
return this->service.clear(this->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 boost::asio::error::operation_aborted
* error code.
*
* Cancellation does not alter the set of registered signals.
*
* @throws boost::system::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()
{
boost::system::error_code ec;
this->service.cancel(this->implementation, ec);
boost::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 boost::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.
*/
boost::system::error_code cancel(boost::system::error_code& ec)
{
return this->service.cancel(this->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 boost::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 boost::system::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
* boost::asio::io_service::post().
*/
template <typename SignalHandler>
BOOST_ASIO_INITFN_RESULT_TYPE(SignalHandler,
void (boost::system::error_code, int))
async_wait(BOOST_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.
BOOST_ASIO_SIGNAL_HANDLER_CHECK(SignalHandler, handler) type_check;
return this->service.async_wait(this->implementation,
BOOST_ASIO_MOVE_CAST(SignalHandler)(handler));
}
};
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#endif // BOOST_ASIO_BASIC_SIGNAL_SET_HPP