[#mp_units-quantity_like_traits]
= xref:mp_units.adoc[mp_units]::quantity_like_traits
:relfileprefix: ../
:mrdocs:

Provides support for external quantity‐like types

== Synopsis

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

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<typename T>
struct quantity_like_traits;
----

== Description

The type trait should provide the `reference` object, a type alias `rep,` and static member functions `to_numerical_value(T)` that returns the raw value of the quantity and `from_numerical_value(rep)` that returns `T` from `rep.`

If the following expression is `true,` the specified conversion will be explicit: ‐ `explicit_import` for the conversion from `T` to a `quantity` type, ‐ `explicit_export` for the conversion from a `quantity` type to `T.`

Usage example can be found in `mp‐units/systems/si/chrono.h` header file.

== Template Parameters

[cols=2]
|===
| Name
| Description
| *T*
| the type to provide support for
|===


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