include/boost/corosio/wait_traits.hpp

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wait_traits.hpp

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<unknown function 55> :55 – – – boost::corosio::wait_traits<boost::corosio::wall_clock>::to_wait_duration(std::chrono::duration<long, std::ratio<1l, 1000000000l> >) :55 2x 100.0% 100.0% boost::corosio::wait_traits<std::chrono::_V2::system_clock>::to_wait_duration(std::chrono::duration<long, std::ratio<1l, 1000000000l> >) :55 0 0.0% 0.0%

Line	Hits	Source Code
1		//
2		// Copyright (c) 2026 Steve Gerbino
3		// Copyright (c) 2026 Michael Vandeberg
4		//
5		// Distributed under the Boost Software License, Version 1.0. (See accompanying
6		// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7		//
8		// Official repository: https://github.com/cppalliance/corosio
9		//
10
11		#ifndef BOOST_COROSIO_WAIT_TRAITS_HPP
12		#define BOOST_COROSIO_WAIT_TRAITS_HPP
13
14		#include <boost/corosio/detail/config.hpp>
15
16		#include <concepts>
17
18		namespace boost::corosio {
19
20		/** Default wait traits for clock-based delays.
21
22		Controls how much of the remaining time a single underlying
23		steady-clock wait may cover before `Clock::now()` is re-read.
24		A larger value costs fewer wakeups; a smaller value bounds how
25		late an adjustment of `Clock` ( e.g. a stepped time-of-day
26		clock ) is observed. The default covers the full remaining
27		duration, which is exact for clocks that advance in lockstep
28		with the machine's monotonic clock.
29
30		@par Example
31		@par !example capped_traits
32
33		@tparam Clock The clock type whose durations are converted.
34
35		@see delay
36		*/
37		template<class Clock>
38		struct wait_traits
39		{
40		/** Convert a remaining duration into a wait duration.
41
42		Should return a positive duration when @p d is positive; a
43		non-positive result degrades to reactor-rate re-checking.
44
45		@par Preconditions
46		Must not throw and must not block — invoked on the
47		io_context's run thread, including from the timer
48		completion path.
49
50		@param d The remaining time until the deadline.
51
52		@return The duration the next underlying wait may cover.
53		*/
54		static typename Clock::duration
55	5x	to_wait_duration(typename Clock::duration d)
56		{
57	5x	return d;
58		}
59		};
60
61		/** Concept for wait-traits policies usable with `Clock`.
62
63		Satisfied when `Traits::to_wait_duration` accepts a
64		`Clock::duration` and returns something convertible back to it.
65		`Traits::to_wait_duration` must not throw.
66		*/
67		template<class Traits, class Clock>
68		concept WaitTraits = requires(typename Clock::duration d)
69		{
70		{ Traits::to_wait_duration(d) }
71		-> std::convertible_to<typename Clock::duration>;
72		};
73
74		} // namespace boost::corosio
75
76		#endif
77