tmp/tmpb8xhstdk/{from.md → to.md}
RENAMED
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@@ -10,60 +10,60 @@ induces a “quality of implementation” delay, expressed as duration Dᵢ.
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Ideally, this delay would be zero. Further, any contention for processor
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and memory resources induces a “quality of management” delay, expressed
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as duration Dₘ. The delay durations may vary from timeout to timeout,
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but in all cases shorter is better.
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The
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-
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-
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-
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The
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specifies a time point. These functions produce absolute timeouts.
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Implementations should use the clock specified in the time point to
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measure time for these functions. Given a clock time point argument Cₜ,
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the clock time point of the return from timeout should be Cₜ + Dᵢ + Dₘ
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when the clock is not adjusted during the timeout. If the clock is
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adjusted to the time Cₐ during the timeout, the behavior should be as
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follows:
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- if Cₐ > Cₜ, the waiting function should wake as soon as possible,
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Cₐ + Dᵢ + Dₘ, since the timeout is already satisfied.
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specification may result in the total duration of the wait decreasing
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when measured against a steady clock.
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- if Cₐ
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`Clock::now()` returns a time Cₙ
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\[*Note
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against a steady clock. When the clock is adjusted forwards, this
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specification
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when measured against a steady clock. — *end note*]
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An implementation
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[*Note
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when the clock is adjusted forwards. — *end note*]
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[*Note
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a CPU time clock, these timeouts might not provide useful
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functionality. — *end note*]
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The resolution of timing provided by an implementation depends on both
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operating system and hardware. The finest resolution provided by an
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implementation is called the *native resolution*.
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Implementation-provided clocks that are used for these functions
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-
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A function that takes an argument which specifies a timeout will throw
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if, during its execution, a clock, time point, or time duration throws
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an exception. Such exceptions are referred to as *timeout-related
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exceptions*.
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[*Note
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supplied by the implementation as specified in [[time.clock]] do not
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throw exceptions. — *end note*]
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Ideally, this delay would be zero. Further, any contention for processor
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and memory resources induces a “quality of management” delay, expressed
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as duration Dₘ. The delay durations may vary from timeout to timeout,
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but in all cases shorter is better.
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+
The functions whose names end in `_for` take an argument that specifies
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a duration. These functions produce relative timeouts. Implementations
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should use a steady clock to measure time for these functions.[^1] Given
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a duration argument Dₜ, the real-time duration of the timeout is
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Dₜ + Dᵢ + Dₘ.
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The functions whose names end in `_until` take an argument that
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specifies a time point. These functions produce absolute timeouts.
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Implementations should use the clock specified in the time point to
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measure time for these functions. Given a clock time point argument Cₜ,
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the clock time point of the return from timeout should be Cₜ + Dᵢ + Dₘ
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when the clock is not adjusted during the timeout. If the clock is
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adjusted to the time Cₐ during the timeout, the behavior should be as
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follows:
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+
- if Cₐ > Cₜ, the waiting function should wake as soon as possible,
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+
i.e., Cₐ + Dᵢ + Dₘ, since the timeout is already satisfied. This
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specification may result in the total duration of the wait decreasing
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+
when measured against a steady clock.
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+
- if Cₐ ≤ Cₜ, the waiting function should not time out until
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`Clock::now()` returns a time Cₙ ≥ Cₜ, i.e., waking at Cₜ + Dᵢ + Dₘ.
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\[*Note 1*: When the clock is adjusted backwards, this specification
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can result in the total duration of the wait increasing when measured
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against a steady clock. When the clock is adjusted forwards, this
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specification can result in the total duration of the wait decreasing
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when measured against a steady clock. — *end note*]
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+
An implementation returns from such a timeout at any point from the time
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specified above to the time it would return from a steady-clock relative
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timeout on the difference between Cₜ and the time point of the call to
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the `_until` function.
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[*Note 2*: Implementations should decrease the duration of the wait
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when the clock is adjusted forwards. — *end note*]
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[*Note 3*: If the clock is not synchronized with a steady clock, e.g.,
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a CPU time clock, these timeouts might not provide useful
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functionality. — *end note*]
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The resolution of timing provided by an implementation depends on both
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operating system and hardware. The finest resolution provided by an
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implementation is called the *native resolution*.
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+
Implementation-provided clocks that are used for these functions meet
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the *Cpp17TrivialClock* requirements [[time.clock.req]].
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A function that takes an argument which specifies a timeout will throw
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if, during its execution, a clock, time point, or time duration throws
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an exception. Such exceptions are referred to as *timeout-related
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exceptions*.
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+
[*Note 4*: Instantiations of clock, time point and duration types
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supplied by the implementation as specified in [[time.clock]] do not
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throw exceptions. — *end note*]
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