1//
2// basic_signal_set.hpp
3// ~~~~~~~~~~~~~~~~~~~~
4//
5// Copyright (c) 2003-2015 Christopher M. Kohlhoff (chris at kohlhoff dot com)
6//
7// Distributed under the Boost Software License, Version 1.0. (See accompanying
8// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
9//
10
11#ifndef BOOST_ASIO_BASIC_SIGNAL_SET_HPP
12#define BOOST_ASIO_BASIC_SIGNAL_SET_HPP
13
14#if defined(_MSC_VER) && (_MSC_VER >= 1200)
15# pragma once
16#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
17
18#include <boost/asio/detail/config.hpp>
19
20#include <boost/asio/basic_io_object.hpp>
21#include <boost/asio/detail/handler_type_requirements.hpp>
22#include <boost/asio/detail/throw_error.hpp>
23#include <boost/asio/error.hpp>
24#include <boost/asio/signal_set_service.hpp>
25
26#include <boost/asio/detail/push_options.hpp>
27
28namespace boost {
29namespace asio {
30
31/// Provides signal functionality.
32/**
33 * The basic_signal_set class template provides the ability to perform an
34 * asynchronous wait for one or more signals to occur.
35 *
36 * Most applications will use the boost::asio::signal_set typedef.
37 *
38 * @par Thread Safety
39 * @e Distinct @e objects: Safe.@n
40 * @e Shared @e objects: Unsafe.
41 *
42 * @par Example
43 * Performing an asynchronous wait:
44 * @code
45 * void handler(
46 * const boost::system::error_code& error,
47 * int signal_number)
48 * {
49 * if (!error)
50 * {
51 * // A signal occurred.
52 * }
53 * }
54 *
55 * ...
56 *
57 * // Construct a signal set registered for process termination.
58 * boost::asio::signal_set signals(io_service, SIGINT, SIGTERM);
59 *
60 * // Start an asynchronous wait for one of the signals to occur.
61 * signals.async_wait(handler);
62 * @endcode
63 *
64 * @par Queueing of signal notifications
65 *
66 * If a signal is registered with a signal_set, and the signal occurs when
67 * there are no waiting handlers, then the signal notification is queued. The
68 * next async_wait operation on that signal_set will dequeue the notification.
69 * If multiple notifications are queued, subsequent async_wait operations
70 * dequeue them one at a time. Signal notifications are dequeued in order of
71 * ascending signal number.
72 *
73 * If a signal number is removed from a signal_set (using the @c remove or @c
74 * erase member functions) then any queued notifications for that signal are
75 * discarded.
76 *
77 * @par Multiple registration of signals
78 *
79 * The same signal number may be registered with different signal_set objects.
80 * When the signal occurs, one handler is called for each signal_set object.
81 *
82 * Note that multiple registration only works for signals that are registered
83 * using Asio. The application must not also register a signal handler using
84 * functions such as @c signal() or @c sigaction().
85 *
86 * @par Signal masking on POSIX platforms
87 *
88 * POSIX allows signals to be blocked using functions such as @c sigprocmask()
89 * and @c pthread_sigmask(). For signals to be delivered, programs must ensure
90 * that any signals registered using signal_set objects are unblocked in at
91 * least one thread.
92 */
93template <typename SignalSetService = signal_set_service>
94class basic_signal_set
95 : public basic_io_object<SignalSetService>
96{
97public:
98 /// Construct a signal set without adding any signals.
99 /**
100 * This constructor creates a signal set without registering for any signals.
101 *
102 * @param io_service The io_service object that the signal set will use to
103 * dispatch handlers for any asynchronous operations performed on the set.
104 */
105 explicit basic_signal_set(boost::asio::io_service& io_service)
106 : basic_io_object<SignalSetService>(io_service)
107 {
108 }
109
110 /// Construct a signal set and add one signal.
111 /**
112 * This constructor creates a signal set and registers for one signal.
113 *
114 * @param io_service The io_service object that the signal set will use to
115 * dispatch handlers for any asynchronous operations performed on the set.
116 *
117 * @param signal_number_1 The signal number to be added.
118 *
119 * @note This constructor is equivalent to performing:
120 * @code boost::asio::signal_set signals(io_service);
121 * signals.add(signal_number_1); @endcode
122 */
123 basic_signal_set(boost::asio::io_service& io_service, int signal_number_1)
124 : basic_io_object<SignalSetService>(io_service)
125 {
126 boost::system::error_code ec;
127 this->service.add(this->implementation, signal_number_1, ec);
128 boost::asio::detail::throw_error(ec, "add");
129 }
130
131 /// Construct a signal set and add two signals.
132 /**
133 * This constructor creates a signal set and registers for two signals.
134 *
135 * @param io_service The io_service object that the signal set will use to
136 * dispatch handlers for any asynchronous operations performed on the set.
137 *
138 * @param signal_number_1 The first signal number to be added.
139 *
140 * @param signal_number_2 The second signal number to be added.
141 *
142 * @note This constructor is equivalent to performing:
143 * @code boost::asio::signal_set signals(io_service);
144 * signals.add(signal_number_1);
145 * signals.add(signal_number_2); @endcode
146 */
147 basic_signal_set(boost::asio::io_service& io_service, int signal_number_1,
148 int signal_number_2)
149 : basic_io_object<SignalSetService>(io_service)
150 {
151 boost::system::error_code ec;
152 this->service.add(this->implementation, signal_number_1, ec);
153 boost::asio::detail::throw_error(ec, "add");
154 this->service.add(this->implementation, signal_number_2, ec);
155 boost::asio::detail::throw_error(ec, "add");
156 }
157
158 /// Construct a signal set and add three signals.
159 /**
160 * This constructor creates a signal set and registers for three signals.
161 *
162 * @param io_service The io_service object that the signal set will use to
163 * dispatch handlers for any asynchronous operations performed on the set.
164 *
165 * @param signal_number_1 The first signal number to be added.
166 *
167 * @param signal_number_2 The second signal number to be added.
168 *
169 * @param signal_number_3 The third signal number to be added.
170 *
171 * @note This constructor is equivalent to performing:
172 * @code boost::asio::signal_set signals(io_service);
173 * signals.add(signal_number_1);
174 * signals.add(signal_number_2);
175 * signals.add(signal_number_3); @endcode
176 */
177 basic_signal_set(boost::asio::io_service& io_service, int signal_number_1,
178 int signal_number_2, int signal_number_3)
179 : basic_io_object<SignalSetService>(io_service)
180 {
181 boost::system::error_code ec;
182 this->service.add(this->implementation, signal_number_1, ec);
183 boost::asio::detail::throw_error(ec, "add");
184 this->service.add(this->implementation, signal_number_2, ec);
185 boost::asio::detail::throw_error(ec, "add");
186 this->service.add(this->implementation, signal_number_3, ec);
187 boost::asio::detail::throw_error(ec, "add");
188 }
189
190 /// Add a signal to a signal_set.
191 /**
192 * This function adds the specified signal to the set. It has no effect if the
193 * signal is already in the set.
194 *
195 * @param signal_number The signal to be added to the set.
196 *
197 * @throws boost::system::system_error Thrown on failure.
198 */
199 void add(int signal_number)
200 {
201 boost::system::error_code ec;
202 this->service.add(this->implementation, signal_number, ec);
203 boost::asio::detail::throw_error(ec, "add");
204 }
205
206 /// Add a signal to a signal_set.
207 /**
208 * This function adds the specified signal to the set. It has no effect if the
209 * signal is already in the set.
210 *
211 * @param signal_number The signal to be added to the set.
212 *
213 * @param ec Set to indicate what error occurred, if any.
214 */
215 boost::system::error_code add(int signal_number,
216 boost::system::error_code& ec)
217 {
218 return this->service.add(this->implementation, signal_number, ec);
219 }
220
221 /// Remove a signal from a signal_set.
222 /**
223 * This function removes the specified signal from the set. It has no effect
224 * if the signal is not in the set.
225 *
226 * @param signal_number The signal to be removed from the set.
227 *
228 * @throws boost::system::system_error Thrown on failure.
229 *
230 * @note Removes any notifications that have been queued for the specified
231 * signal number.
232 */
233 void remove(int signal_number)
234 {
235 boost::system::error_code ec;
236 this->service.remove(this->implementation, signal_number, ec);
237 boost::asio::detail::throw_error(ec, "remove");
238 }
239
240 /// Remove a signal from a signal_set.
241 /**
242 * This function removes the specified signal from the set. It has no effect
243 * if the signal is not in the set.
244 *
245 * @param signal_number The signal to be removed from the set.
246 *
247 * @param ec Set to indicate what error occurred, if any.
248 *
249 * @note Removes any notifications that have been queued for the specified
250 * signal number.
251 */
252 boost::system::error_code remove(int signal_number,
253 boost::system::error_code& ec)
254 {
255 return this->service.remove(this->implementation, signal_number, ec);
256 }
257
258 /// Remove all signals from a signal_set.
259 /**
260 * This function removes all signals from the set. It has no effect if the set
261 * is already empty.
262 *
263 * @throws boost::system::system_error Thrown on failure.
264 *
265 * @note Removes all queued notifications.
266 */
267 void clear()
268 {
269 boost::system::error_code ec;
270 this->service.clear(this->implementation, ec);
271 boost::asio::detail::throw_error(ec, "clear");
272 }
273
274 /// Remove all signals from a signal_set.
275 /**
276 * This function removes all signals from the set. It has no effect if the set
277 * is already empty.
278 *
279 * @param ec Set to indicate what error occurred, if any.
280 *
281 * @note Removes all queued notifications.
282 */
283 boost::system::error_code clear(boost::system::error_code& ec)
284 {
285 return this->service.clear(this->implementation, ec);
286 }
287
288 /// Cancel all operations associated with the signal set.
289 /**
290 * This function forces the completion of any pending asynchronous wait
291 * operations against the signal set. The handler for each cancelled
292 * operation will be invoked with the boost::asio::error::operation_aborted
293 * error code.
294 *
295 * Cancellation does not alter the set of registered signals.
296 *
297 * @throws boost::system::system_error Thrown on failure.
298 *
299 * @note If a registered signal occurred before cancel() is called, then the
300 * handlers for asynchronous wait operations will:
301 *
302 * @li have already been invoked; or
303 *
304 * @li have been queued for invocation in the near future.
305 *
306 * These handlers can no longer be cancelled, and therefore are passed an
307 * error code that indicates the successful completion of the wait operation.
308 */
309 void cancel()
310 {
311 boost::system::error_code ec;
312 this->service.cancel(this->implementation, ec);
313 boost::asio::detail::throw_error(ec, "cancel");
314 }
315
316 /// Cancel all operations associated with the signal set.
317 /**
318 * This function forces the completion of any pending asynchronous wait
319 * operations against the signal set. The handler for each cancelled
320 * operation will be invoked with the boost::asio::error::operation_aborted
321 * error code.
322 *
323 * Cancellation does not alter the set of registered signals.
324 *
325 * @param ec Set to indicate what error occurred, if any.
326 *
327 * @note If a registered signal occurred before cancel() is called, then the
328 * handlers for asynchronous wait operations will:
329 *
330 * @li have already been invoked; or
331 *
332 * @li have been queued for invocation in the near future.
333 *
334 * These handlers can no longer be cancelled, and therefore are passed an
335 * error code that indicates the successful completion of the wait operation.
336 */
337 boost::system::error_code cancel(boost::system::error_code& ec)
338 {
339 return this->service.cancel(this->implementation, ec);
340 }
341
342 /// Start an asynchronous operation to wait for a signal to be delivered.
343 /**
344 * This function may be used to initiate an asynchronous wait against the
345 * signal set. It always returns immediately.
346 *
347 * For each call to async_wait(), the supplied handler will be called exactly
348 * once. The handler will be called when:
349 *
350 * @li One of the registered signals in the signal set occurs; or
351 *
352 * @li The signal set was cancelled, in which case the handler is passed the
353 * error code boost::asio::error::operation_aborted.
354 *
355 * @param handler The handler to be called when the signal occurs. Copies
356 * will be made of the handler as required. The function signature of the
357 * handler must be:
358 * @code void handler(
359 * const boost::system::error_code& error, // Result of operation.
360 * int signal_number // Indicates which signal occurred.
361 * ); @endcode
362 * Regardless of whether the asynchronous operation completes immediately or
363 * not, the handler will not be invoked from within this function. Invocation
364 * of the handler will be performed in a manner equivalent to using
365 * boost::asio::io_service::post().
366 */
367 template <typename SignalHandler>
368 BOOST_ASIO_INITFN_RESULT_TYPE(SignalHandler,
369 void (boost::system::error_code, int))
370 async_wait(BOOST_ASIO_MOVE_ARG(SignalHandler) handler)
371 {
372 // If you get an error on the following line it means that your handler does
373 // not meet the documented type requirements for a SignalHandler.
374 BOOST_ASIO_SIGNAL_HANDLER_CHECK(SignalHandler, handler) type_check;
375
376 return this->service.async_wait(this->implementation,
377 BOOST_ASIO_MOVE_CAST(SignalHandler)(handler));
378 }
379};
380
381} // namespace asio
382} // namespace boost
383
384#include <boost/asio/detail/pop_options.hpp>
385
386#endif // BOOST_ASIO_BASIC_SIGNAL_SET_HPP
387