[/
/ Copyright (c) 2003-2025 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)
/]
[section:timers Timers]
Long running I/O operations will often have a deadline by which they must have
completed. These deadlines may be expressed as absolute times, but are often
calculated relative to the current time.
As a simple example, to perform a synchronous wait operation on a timer using a
relative time one may write:
io_context i;
...
steady_timer t(i);
t.expires_after(chrono::seconds(5));
t.wait();
More commonly, a program will perform an asynchronous wait operation on a
timer:
void handler(asio::error_code ec) { ... }
...
io_context i;
...
steady_timer t(i);
t.expires_after(chrono::milliseconds(400));
t.async_wait(handler);
...
i.run();
The deadline associated with a timer may also be obtained as an absolute time:
steady_timer::time_point time_of_expiry = t.expiry();
which allows composition of timers:
steady_timer t2(i);
t2.expires_at(t.expiry() + chrono::seconds(30));
[heading See Also]
[link asio.reference.basic_waitable_timer basic_waitable_timer],
[link asio.reference.steady_timer steady_timer],
[link asio.reference.system_timer system_timer],
[link asio.reference.high_resolution_timer high_resolution_timer],
[link asio.tutorial.tuttimer1 timer tutorials].
[endsect]
