`mp_units::value_cast`¶

Explicit cast of a quantity point's unit and representation type

Synopsis¶

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

template<Unit auto ToU, typename ToRep, typename FwdQP, RoundingPolicy Policy = truncated_t,
         QuantityPoint QP = std::remove_cvref_t<FwdQP>>
  requires UnitOf<MP_UNITS_NTTP_TYPE(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 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 qp = value_cast<us, int>(quantity_point{1.23 * ms});

Return Value¶

Note

The return value should not be discarded.

Template Parameters¶

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

Parameters¶

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

mp_units::value_cast¶