[constraints.overview]

# 16 Library introduction [[library]](./#library)

## 16.4 Library-wide requirements [[requirements]](requirements#constraints.overview)

### 16.4.5 Constraints on programs [[constraints]](constraints#overview)

#### 16.4.5.1 Overview [constraints.overview]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/lib-intro.tex#L2978)

Subclause [[constraints]](constraints "16.4.5 Constraints on programs") describes restrictions on C++ programs that use the facilities of
the C++ standard library[.](#1.sentence-1)

The following subclauses specify constraints on the
program's use of [namespaces](namespace.std "16.4.5.2.1 Namespace std [namespace.std]"), its use of various [reserved
names](reserved.names "16.4.5.3 Reserved names [reserved.names]"), its use of [headers](alt.headers "16.4.5.4 Headers [alt.headers]"), its use of
standard library classes as base classes ([[derived.classes]](derived.classes "16.4.5.5 Derived classes")), its
definitions of [replacement functions](replacement.functions "16.4.5.6 Replacement functions [replacement.functions]"), and its
installation of [handler functions](handler.functions "16.4.5.7 Handler functions [handler.functions]") during execution[.](#1.sentence-2)