[#mp_units-utility-operator_minus-06]
= xref:mp_units.adoc[mp_units]::xref:mp_units/utility.adoc[utility]::operator‐
:relfileprefix: ../../
:mrdocs:

Unary minus operators

== Synopses

Declared in `<mp‐units/utility/constrained.h>`

Negates the wrapped value


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/utility/constrained.adoc[constrained<decltype(‐std::declval<T>()), ErrorPolicy>]
xref:mp_units/utility/operator_minus-0d1.adoc[operator‐](xref:mp_units/utility/constrained.adoc[constrained] const& x);
----

[.small]#xref:mp_units/utility/operator_minus-0d1.adoc[_» more..._]#

Subtracts a `safe_int` from an integral scalar, checking for overflow.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/utility/safe_int-07.adoc[safe_int</* implementation-defined */, ErrorPolicy>]
xref:mp_units/utility/operator_minus-02.adoc[operator‐](
    U lhs,
    xref:mp_units/utility/safe_int-07.adoc[safe_int] rhs);
----

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

Subtracts a `safe_int` from a floating‐point value.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
auto
xref:mp_units/utility/operator_minus-03.adoc[operator‐](
    U lhs,
    xref:mp_units/utility/safe_int-07.adoc[safe_int] rhs)
requires requires { lhs ‐ static_cast<U>(rhs.value_); };
----

[.small]#xref:mp_units/utility/operator_minus-03.adoc[_» more..._]#

Subtracts an integral scalar from a `safe_int`, checking for overflow.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/utility/safe_int-07.adoc[safe_int</* implementation-defined */, ErrorPolicy>]
xref:mp_units/utility/operator_minus-0de.adoc[operator‐](
    xref:mp_units/utility/safe_int-07.adoc[safe_int] lhs,
    U rhs);
----

[.small]#xref:mp_units/utility/operator_minus-0de.adoc[_» more..._]#

Subtracts a floating‐point value from a `safe_int`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
auto
xref:mp_units/utility/operator_minus-04.adoc[operator‐](
    xref:mp_units/utility/safe_int-07.adoc[safe_int] lhs,
    U rhs)
requires requires { static_cast<U>(lhs.value_) ‐ rhs; };
----

[.small]#xref:mp_units/utility/operator_minus-04.adoc[_» more..._]#

Computes the difference of `lhs` and `rhs.`


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/utility/safe_int-07.adoc[safe_int</* implementation-defined */, ErrorPolicy>]
xref:mp_units/utility/operator_minus-09.adoc[operator‐](
    xref:mp_units/utility/safe_int-07.adoc[safe_int] lhs,
    xref:mp_units/utility/safe_int-07.adoc[safe_int] rhs);
----

[.small]#xref:mp_units/utility/operator_minus-09.adoc[_» more..._]#

Subtracts a constrained value from a safe_int


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/utility/safe_int-07.adoc[safe_int</* implementation-defined */, ErrorPolicy>]
xref:mp_units/utility/operator_minus-0b.adoc[operator‐](
    xref:mp_units/utility/safe_int-07.adoc[safe_int] lhs,
    xref:mp_units/utility/constrained.adoc[constrained<U, CP>] rhs);
----

[.small]#xref:mp_units/utility/operator_minus-0b.adoc[_» more..._]#

Subtracts a non‐integral constrained value from a safe_int


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/utility/constrained.adoc[constrained<decltype(std::declval<T>() ‐ std::declval<U>()), CP>]
xref:mp_units/utility/operator_minus-07.adoc[operator‐](
    xref:mp_units/utility/safe_int-07.adoc[safe_int] lhs,
    xref:mp_units/utility/constrained.adoc[constrained<U, CP>] const& rhs);
----

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

Subtracts a safe_int from a constrained value


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/utility/safe_int-07.adoc[safe_int</* implementation-defined */, ErrorPolicy>]
xref:mp_units/utility/operator_minus-05.adoc[operator‐](
    xref:mp_units/utility/constrained.adoc[constrained<U, CP>] lhs,
    xref:mp_units/utility/safe_int-07.adoc[safe_int] rhs);
----

[.small]#xref:mp_units/utility/operator_minus-05.adoc[_» more..._]#

Subtracts a safe_int from a non‐integral constrained value


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
[[nodiscard]]
constexpr
xref:mp_units/utility/constrained.adoc[constrained<decltype(std::declval<U>() ‐ std::declval<T>()), CP>]
xref:mp_units/utility/operator_minus-01.adoc[operator‐](
    xref:mp_units/utility/constrained.adoc[constrained<U, CP>] const& lhs,
    xref:mp_units/utility/safe_int-07.adoc[safe_int] rhs);
----

[.small]#xref:mp_units/utility/operator_minus-01.adoc[_» more..._]#

== Return Value

* the wrapped result of negating `x`
* the difference, as a `safe_int` of the promoted result type; triggers `ErrorPolicy::on_overflow` on overflow
* the difference between `lhs` and the wrapped value
* the difference between the wrapped value and `rhs`
* the result of `lhs ‐ rhs`; triggers `ErrorPolicy::on_overflow` on overflow
* the wrapped difference of the underlying values

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

[cols="1,4"]
|===
| Name| Description
| *U*
| the integral scalar type
|===

== Parameters

[cols="1,4"]
|===
| Name| Description
| *x*
| the wrapped value to negate
| *lhs*
| the integral scalar operand
| *rhs*
| the `safe_int` to subtract
|===


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