[#mp_units-quantity-01-operator_dec-07]
= xref:mp_units.adoc[mp_units]::xref:mp_units/quantity-01.adoc[quantity]::operator‐‐
:relfileprefix: ../../
:mrdocs:

Decrement operators

== Synopses

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

Pre‐decrements the numerical value.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
constexpr
xref:mp_units/quantity-01.adoc[quantity]&
xref:mp_units/quantity-01/operator_dec-0d.adoc[operator‐‐]() &
requires requires(rep& v) {
      { ‐‐v } ‐> std::same_as<rep&>;
    };
----

[.small]#xref:mp_units/quantity-01/operator_dec-0d.adoc[_» more..._]#

Post‐decrements the numerical value.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/QuantityOf.adoc[QuantityOf<quantity_spec>] auto
xref:mp_units/quantity-01/operator_dec-09.adoc[operator‐‐](int unused_tag)
requires requires(rep& v) {
      { v‐‐ } ‐> std::common_with<rep>;
    };
----

[.small]#xref:mp_units/quantity-01/operator_dec-09.adoc[_» more..._]#

== Return Value

* `*this`, after the decrement.
* A quantity holding the value of `*this` before the decrement.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *unused_tag*
| An unused tag parameter that distinguishes this overload as the post‐decrement operator.
|===


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