[diff.mods.to.declarations]

# Annex C (informative) Compatibility [[diff]](./#diff)

## C.8 C standard library [[diff.library]](diff.library#diff.mods.to.declarations)

### C.8.4 Modifications to declarations [diff.mods.to.declarations]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/compatibility.tex#L3769)

Header [<cstring>](cstring.syn#header:%3ccstring%3e "27.5.1 Header <cstring> synopsis [cstring.syn]"):
The following functions have different declarations:

- [(1.1)](#1.1)

strchr

- [(1.2)](#1.2)

strpbrk

- [(1.3)](#1.3)

strrchr

- [(1.4)](#1.4)

strstr

- [(1.5)](#1.5)

memchr

Subclause [[cstring.syn]](cstring.syn "27.5.1 Header <cstring> synopsis") describes the changes[.](#1.sentence-2)

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/compatibility.tex#L3782)

Header [<cwchar>](cwchar.syn#header:%3ccwchar%3e "28.7.3 Header <cwchar> synopsis [cwchar.syn]"):
The following functions have different declarations:

- [(2.1)](#2.1)

wcschr

- [(2.2)](#2.2)

wcspbrk

- [(2.3)](#2.3)

wcsrchr

- [(2.4)](#2.4)

wcsstr

- [(2.5)](#2.5)

wmemchr

Subclause [[cwchar.syn]](cwchar.syn "28.7.3 Header <cwchar> synopsis") describes the changes[.](#2.sentence-2)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/compatibility.tex#L3795)

Header [<cstddef>](cstddef.syn#header:%3ccstddef%3e "17.2.1 Header <cstddef> synopsis [cstddef.syn]") declares the names nullptr_t, byte, and to_integer,
and the operators and operator templates in [[support.types.byteops]](support.types.byteops "17.2.5 byte type operations"),
in addition to the names declared in[<stddef.h>](support.c.headers.general#header:%3cstddef.h%3e "17.15.1 General [support.c.headers.general]") in the C standard library[.](#3.sentence-1)