[container.intro.reqmts]

# 23 Containers library [[containers]](./#containers)

## 23.2 Requirements [[container.requirements]](container.requirements#container.intro.reqmts)

### 23.2.2 General containers [[container.requirements.general]](container.requirements.general#container.intro.reqmts)

#### 23.2.2.1 Introduction [container.intro.reqmts]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/containers.tex#L77)

In [[container.requirements.general]](container.requirements.general "23.2.2 General containers"),

- [(1.1)](#1.1)

X denotes a container class containing objects of type T,

- [(1.2)](#1.2)

a denotes a value of type X,

- [(1.3)](#1.3)

b and c denote values of type (possibly const) X,

- [(1.4)](#1.4)

i and j denote values of type (possibly const) X​::​iterator,

- [(1.5)](#1.5)

u denotes an identifier,

- [(1.6)](#1.6)

v denotes an lvalue of type (possibly const) X or
an rvalue of type const X,

- [(1.7)](#1.7)

s and t denote non-const lvalues of type X, and

- [(1.8)](#1.8)

rv denotes a non-const rvalue of type X[.](#1.sentence-1)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/containers.tex#L99)

The following exposition-only concept is used in the definition of containers:template<class R, class T>concept [*container-compatible-range*](#concept:container-compatible-range "23.2.2.1 Introduction [container.intro.reqmts]") = // *exposition only* ranges::[input_range](range.refinements#concept:input_range "25.4.6 Other range refinements [range.refinements]")<R> && [convertible_to](concept.convertible#concept:convertible_to "18.4.4 Concept convertible_­to [concept.convertible]")<ranges::range_reference_t<R>, T>;