[concepts.compare.general]

# 18 Concepts library [[concepts]](./#concepts)

## 18.5 Comparison concepts [[concepts.compare]](concepts.compare#general)

### 18.5.1 General [concepts.compare.general]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/concepts.tex#L843)

Subclause [[concepts.compare]](concepts.compare "18.5 Comparison concepts") describes concepts that establish relationships and orderings
on values of possibly differing object types[.](#1.sentence-1)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/concepts.tex#L847)

Given an expression E and a type C,
let *CONVERT_TO_LVALUE*<C>(E) be:

- [(2.1)](#2.1)

static_cast<const C&>(as_const(E)) if that is a valid expression, and

- [(2.2)](#2.2)

static_cast<const C&>(std​::​move(E)) otherwise[.](#2.sentence-1)