54 lines
1.5 KiB
Plaintext
54 lines
1.5 KiB
Plaintext
[/
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/ Copyright (c) 2003-2023 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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[section:timers Timers]
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Long running I/O operations will often have a deadline by which they must have
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completed. These deadlines may be expressed as absolute times, but are often
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calculated relative to the current time.
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As a simple example, to perform a synchronous wait operation on a timer using a
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relative time one may write:
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io_context i;
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...
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steady_timer t(i);
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t.expires_after(chrono::seconds(5));
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t.wait();
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More commonly, a program will perform an asynchronous wait operation on a
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timer:
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void handler(boost::system::error_code ec) { ... }
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...
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io_context i;
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...
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steady_timer t(i);
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t.expires_after(chrono::milliseconds(400));
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t.async_wait(handler);
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...
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i.run();
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The deadline associated with a timer may also be obtained as an absolute time:
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steady_timer::time_point time_of_expiry = t.expiry();
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which allows composition of timers:
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steady_timer t2(i);
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t2.expires_at(t.expiry() + chrono::seconds(30));
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[heading See Also]
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[link boost_asio.reference.basic_waitable_timer basic_waitable_timer],
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[link boost_asio.reference.steady_timer steady_timer],
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[link boost_asio.reference.system_timer system_timer],
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[link boost_asio.reference.high_resolution_timer high_resolution_timer],
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[link boost_asio.tutorial.tuttimer1 timer tutorials].
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[endsect]
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