[#mp_units-quantity-01-2constructor-0b]
= xref:mp_units.adoc[mp_units]::xref:mp_units/quantity-01.adoc[quantity]::quantity
:relfileprefix: ../../
:mrdocs:

Constructs a quantity from a numerical value and a reference with a different unit.

== Synopsis

Declared in `<mp‐units/framework/quantity.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename FwdValue,
    xref:mp_units/Reference-0ba.adoc[Reference] R2>
requires (!equivalent(unit, get_unit(R2{}))) &&
            detail::QuantityConstructibleFrom<quantity, quantity<R2{}, std::remove_cvref_t<FwdValue>>>
[[nodiscard]]
constexpr
quantity(
    FwdValue&& val,
    R2 ref);
----

== Description

The value is first converted to the quantity of reference `ref` and then scaled to this quantity's unit.

== Return Value

[NOTE]
====
The return value https://en.cppreference.com/cpp/language/attributes/nodiscard[should not be discarded^].
====
== Parameters

[cols="1,4"]
|===
| Name| Description
| *val*
| the numerical value to store, expressed in the unit of `ref`
| *ref*
| a reference whose unit is not equivalent to `unit`
|===


[.small]#Created with https://www.mrdocs.com[MrDocs]#