[support.rtti.general]

# 17 Language support library [[support]](./#support)

## 17.7 Type identification [[support.rtti]](support.rtti#general)

### 17.7.1 General [support.rtti.general]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/support.tex#L3264)

The header [<typeinfo>](typeinfo.syn#header:%3ctypeinfo%3e "17.7.2 Header <typeinfo> synopsis [typeinfo.syn]") defines a
type associated with type information generated by the implementation[.](#1.sentence-1)

It also defines two types for reporting dynamic type identification errors[.](#1.sentence-2)

The header [<typeindex>](type.index.synopsis#header:%3ctypeindex%3e "17.7.6 Header <typeindex> synopsis [type.index.synopsis]") defines
a wrapper type for use as an index type in associative containers ([[associative]](associative "23.4 Associative containers"))
and in unordered associative containers ([[unord]](unord "23.5 Unordered associative containers"))[.](#1.sentence-3)