[#mp_units-operator_3way-06f]
= xref:mp_units.adoc[mp_units]::operator<=>
:relfileprefix: ../
:mrdocs:

Compares two quantity characters lexicographically on (order, field)

== Synopses

Declared in `<mp‐units/ext/fixed_string.h>`

Compares two quantity characters lexicographically on (order, field)


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
auto
xref:mp_units/operator_3way-014.adoc[operator<=>](
    xref:mp_units/quantity_character.adoc[quantity_character] lhs,
    xref:mp_units/quantity_character.adoc[quantity_character] rhs) = default;
----

[.small]#xref:mp_units/operator_3way-014.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename CharT,
    std::size_t N,
    std::size_t N2>
[[nodiscard]]
constexpr
auto
xref:mp_units/operator_3way-0e.adoc[operator<=>](
    xref:mp_units/basic_fixed_string-08.adoc[basic_fixed_string<CharT, N>] const& lhs,
    xref:mp_units/basic_fixed_string-08.adoc[basic_fixed_string<CharT, N2>] const& rhs);
----

[.small]#xref:mp_units/operator_3way-0e.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    typename CharT,
    std::size_t N,
    std::size_t N2>
[[nodiscard]]
consteval
auto
xref:mp_units/operator_3way-0d.adoc[operator<=>](
    xref:mp_units/basic_fixed_string-08.adoc[basic_fixed_string<CharT, N>] const& lhs,
    CharT const(& rhs)[]);
----

[.small]#xref:mp_units/operator_3way-0d.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    auto R1,
    typename Rep1>
requires std::three_way_comparable<Rep1> && requires { representation_values<Rep1>::zero(); }
[[nodiscard]]
constexpr
auto
xref:mp_units/operator_3way-015.adoc[operator<=>](
    xref:mp_units/quantity-01.adoc[quantity<R1, Rep1>] const& lhs,
    /* implementation-defined */ rhs);
----

[.small]#xref:mp_units/operator_3way-015.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    auto R1,
    typename Rep1,
    auto R2,
    typename Rep2>
requires CommonlyComparableQuantities<quantity<R1, Rep1>, quantity<R2, Rep2>> &&
             std::three_way_comparable<typename std::common_type_t<quantity<R1, Rep1>, quantity<R2, Rep2>>::rep>
[[nodiscard]]
constexpr
auto
xref:mp_units/operator_3way-04c.adoc[operator<=>](
    xref:mp_units/quantity-01.adoc[quantity<R1, Rep1>] const& lhs,
    xref:mp_units/quantity-01.adoc[quantity<R2, Rep2>] const& rhs);
----

[.small]#xref:mp_units/operator_3way-04c.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    auto R1,
    typename Rep1,
    xref:mp_units/RepresentationOf.adoc[RepresentationOf<get_quantity_spec(R1)>] Value>
requires ImplicitFromNumber<R1> && std::three_way_comparable_with<Rep1, Value>
[[nodiscard]]
constexpr
auto
xref:mp_units/operator_3way-08.adoc[operator<=>](
    xref:mp_units/quantity-01.adoc[quantity<R1, Rep1>] const& lhs,
    Value const& rhs);
----

[.small]#xref:mp_units/operator_3way-08.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    auto R1,
    auto PO1,
    typename Rep1,
    xref:mp_units/QuantityPointOf.adoc[QuantityPointOf<mp_units::detail::get_absolute_point_origin(PO1)>] QP2>
requires std::three_way_comparable_with<quantity<R1, Rep1>, typename QP2::quantity_type>
[[nodiscard]]
constexpr
auto
xref:mp_units/operator_3way-04d.adoc[operator<=>](
    xref:mp_units/quantity_point-08.adoc[quantity_point<R1, PO1, Rep1>] const& lhs,
    QP2 const& rhs);
----

[.small]#xref:mp_units/operator_3way-04d.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    std::size_t N,
    std::size_t M,
    std::size_t N2>
[[nodiscard]]
consteval
auto
xref:mp_units/operator_3way-02.adoc[operator<=>](
    xref:mp_units/symbol_text-032.adoc[symbol_text<N, M>] const& lhs,
    char const(& rhs)[])
requires requires { symbol_text<N, M>(rhs); };
----

[.small]#xref:mp_units/operator_3way-02.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    std::size_t N,
    std::size_t M>
[[nodiscard]]
constexpr
auto
xref:mp_units/operator_3way-07.adoc[operator<=>](
    xref:mp_units/symbol_text-032.adoc[symbol_text<N, M>] const& lhs,
    char rhs) noexcept
requires requires { symbol_text<N, M>(rhs); };
----

[.small]#xref:mp_units/operator_3way-07.adoc[_» more..._]#

Three‐way comparison operator


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    std::size_t N,
    std::size_t M,
    std::size_t N2,
    std::size_t M2>
[[nodiscard]]
constexpr
auto
xref:mp_units/operator_3way-069.adoc[operator<=>](
    xref:mp_units/symbol_text-032.adoc[symbol_text<N, M>] const& lhs,
    xref:mp_units/symbol_text-032.adoc[symbol_text<N2, M2>] const& rhs) noexcept;
----

[.small]#xref:mp_units/operator_3way-069.adoc[_» more..._]#

== Return Value

the lexicographic ordering of `lhs` and `rhs`

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

[cols="1,4"]
|===
| Name| Description
| *lhs*
| first quantity character to compare
| *rhs*
| second quantity character to compare
|===


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