`mp_units::value_cast`¶

Explicit cast of a quantity's representation type

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)

mp_units::value_cast¶