[numeric.requirements]

# 29 Numerics library [[numerics]](./#numerics)

## 29.2 Numeric type requirements [numeric.requirements]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L35)

Thecomplex andvalarray components are parameterized by the type of information they contain and manipulate[.](#1.sentence-1)

A C++ program shall instantiate these components only with a numeric type[.](#1.sentence-2)

A [*numeric type*](#def:type,numeric "29.2 Numeric type requirements [numeric.requirements]") is a cv-unqualified object type T that meets the[*Cpp17DefaultConstructible*](utility.arg.requirements#:Cpp17DefaultConstructible "16.4.4.2 Template argument requirements [utility.arg.requirements]"),[*Cpp17CopyConstructible*](utility.arg.requirements#:Cpp17CopyConstructible "16.4.4.2 Template argument requirements [utility.arg.requirements]"),[*Cpp17CopyAssignable*](utility.arg.requirements#:Cpp17CopyAssignable "16.4.4.2 Template argument requirements [utility.arg.requirements]"), and[*Cpp17Destructible*](utility.arg.requirements#:Cpp17Destructible "16.4.4.2 Template argument requirements [utility.arg.requirements]") requirements ([[utility.arg.requirements]](utility.arg.requirements "16.4.4.2 Template argument requirements"))[.](#1.sentence-3)[239](#footnote-239 "In other words, value types. These include arithmetic types, pointers, the library class complex, and instantiations of valarray for value types.")

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L59)

If any operation on T throws an exception the effects are undefined[.](#2.sentence-1)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L63)

In addition, many member and related functions ofvalarray<T> can be successfully instantiated
and will exhibit well-defined behavior if and only ifT meets additional requirements specified for each such member
or related function[.](#3.sentence-1)

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/numerics.tex#L71)

[*Example [1](#example-1)*:

It is valid to instantiatevalarray<complex>,
butoperator>() will not be successfully instantiated forvalarray<complex> operands, sincecomplex does not have any ordering operators[.](#4.sentence-1)

â *end example*]

[239)](#footnote-239)[239)](#footnoteref-239)

In other words, value types[.](#footnote-239.sentence-1)

These include arithmetic types,
pointers, the library classcomplex,
and instantiations ofvalarray for value types[.](#footnote-239.sentence-2)
