mp_units::value_cast

Synopsis

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

template<
    typename ToRep,
    Unit auto ToU,
    typename FwdQP,
    RoundingPolicy Policy = truncated_t,
    QuantityPoint QP = std::remove_cvref_t<FwdQP>>
requires UnitOf<MP_UNITS_REMOVE_CONST(decltype(ToU)), QP::quantity_spec> &&
           RepresentationOf<ToRep, QP::quantity_spec> && std::constructible_from<ToRep, typename QP::rep> &&
           detail::ExplicitlyCastable<QP::unit, ToU, ToRep> &&
           detail::ValidRoundingPolicyFor<Policy, typename QP::rep, ToRep>
[[nodiscard]]
constexpr
QuantityPoint auto
value_cast(
    FwdQP&& qp,
    Policy policy = Policy{});

Description

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

auto qp = value_cast<int, us>(quantity_point{1.23 * ms});

Return Value

the quantity point converted to unit ToU and representation type ToRep

NOTE

The return value should not be discarded.

Template Parameters

Name	Description
ToRep	a representation type to use for the target quantity
ToU	a unit to use for the target quantity

Parameters

Name	Description
qp	the quantity point to cast
policy	an optional rounding policy (`truncated` when not provided)