[#operator_3way-01]
= operator<=>
:mrdocs:

Three‐way comparison operators

== Synopses

Declared in `<arith_uint256.h>`

Orders identifiers by kind, then by wrapped value.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
auto
xref:operator_3way-09.adoc[operator<=>](
    xref:GenTxid.adoc[GenTxid] const& a,
    xref:GenTxid.adoc[GenTxid] const& b);
----

[.small]#xref:operator_3way-09.adoc[_» more..._]#

Performs a three‐way comparison of two big integers.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
std::strong_ordering
xref:operator_3way-05a.adoc[operator<=>](
    xref:base_uint-02.adoc[base_uint] const& a,
    xref:base_uint-02.adoc[base_uint] const& b);
----

[.small]#xref:operator_3way-05a.adoc[_» more..._]#

Performs a three‐way comparison of two big integers.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
std::strong_ordering
xref:operator_3way-00f.adoc[operator<=>](
    xref:base_uint-02.adoc[base_uint<256>] const& a,
    xref:base_uint-02.adoc[base_uint<256>] const& b);
----

[.small]#xref:operator_3way-00f.adoc[_» more..._]#

Compare two script_verify_flags. <, >, <=, and >= are auto‐generated from this.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
std::strong_ordering
xref:operator_3way-0c.adoc[operator<=>](
    xref:script_verify_flags.adoc[script_verify_flags] const& a,
    xref:script_verify_flags.adoc[script_verify_flags] const& b) noexcept;
----

[.small]#xref:operator_3way-0c.adoc[_» more..._]#

Comparison between two deques, implementing lexicographic ordering on the contents.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
std::strong_ordering
xref:operator_3way-056.adoc[operator<=>](
    xref:VecDeque.adoc[VecDeque] const& a,
    xref:VecDeque.adoc[VecDeque] const& b);
----

[.small]#xref:operator_3way-056.adoc[_» more..._]#

Order two wrapped FeeFracs by feerate.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
std::strong_ordering
xref:operator_3way-00a.adoc[operator<=>](
    xref:ByRatio.adoc[ByRatio] const& a,
    xref:ByRatio.adoc[ByRatio] const& b) noexcept;
----

[.small]#xref:operator_3way-00a.adoc[_» more..._]#

Order two wrapped FeeFracs by feerate, then by reversed size.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
std::strong_ordering
xref:operator_3way-03.adoc[operator<=>](
    xref:ByRatioNegSize.adoc[ByRatioNegSize] const& a,
    xref:ByRatioNegSize.adoc[ByRatioNegSize] const& b) noexcept;
----

[.small]#xref:operator_3way-03.adoc[_» more..._]#

Three‐way compare two fee rates by their fee/vsize ratio.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
std::strong_ordering
xref:operator_3way-08.adoc[operator<=>](
    xref:CFeeRate.adoc[CFeeRate] const& a,
    xref:CFeeRate.adoc[CFeeRate] const& b) noexcept;
----

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

== Return Value

* The ordering of a relative to b.
* The ordering of `a` relative to `b.`
* The ordering of a relative to b, comparing elements in order then size.
* The ordering of the feerates of a and b.
* The ordering of a relative to b, comparing feerate first and larger size first on ties.
* Ordering of `a` relative to `b`.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *a*
| The left‐hand identifier.
| *b*
| The right‐hand identifier.
|===


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