Explicit cast of a quantity's unit and representation type

Synopsis

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

template<
    Unit auto ToU,
    typename ToRep,
    typename FwdQ,
    Quantity Q = std::remove_cvref_t<FwdQ>>
requires (MP_UNITS_WEAK_UNIT_OF(MP_UNITS_REMOVE_CONST(decltype(ToU)), Q::quantity_spec)) &&
          RepresentationOf<ToRep, Q::quantity_spec> && std::constructible_from<ToRep, typename Q::rep> &&
          detail::SaneScaling<Q::unit, ToU, ToRep>
[[nodiscard]]
constexpr
Quantity auto
value_cast(FwdQ&& q);

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<us, int>(1.23 ms);

Template Parameters

Name

Description

ToU

a unit to use for the target quantity

ToRep

a representation type to use for the target quantity

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