mp_units::value_cast

Synopsis

Declared in <mp-units/framework/value_cast.h>

template<
    typename ToRep,
    typename FwdQ,
    RoundingPolicy Policy = truncated_t,
    Quantity Q = std::remove_cvref_t<FwdQ>>
requires RepresentationOf<ToRep, Q::quantity_spec> && std::constructible_from<ToRep, typename Q::rep> &&
           detail::ValidRoundingPolicyFor<Policy, typename Q::rep, ToRep>
[[nodiscard]]
constexpr
quantity<Q::reference, ToRep>
value_cast(
    FwdQ&& q,
    Policy = Policy{});

Description

Implicit conversions between quantities of different types are allowed only for "safe" (e.g. non-truncating) conversion. In truncating cases an explicit cast have to be used.

auto q = value_cast<int>(1.23 * ms); auto r = value_cast<int>(1.55 * ms, rounded);

Return Value

A quantity

NOTE

The return value should not be discarded.

Template Parameters

Name	Description
ToRep	a representation type to use for a target quantity

Parameters

Name	Description
policy	an optional rounding policy (`truncated` when not provided)