[fs.path.append]

# 31 Input/output library [[input.output]](./#input.output)

## 31.12 File systems [[filesystems]](filesystems#fs.path.append)

### 31.12.6 Class path [[fs.class.path]](fs.class.path#fs.path.append)

#### 31.12.6.5 Members [[fs.path.member]](fs.path.member#fs.path.append)

#### 31.12.6.5.3 Appends [fs.path.append]

[1](#1)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L14340)

The append operations use operator/= to denote their semantic effect of appending[*preferred-separator*](fs.path.generic#nt:preferred-separator "31.12.6.2 Generic pathname format [fs.path.generic]") when needed[.](#1.sentence-1)

[🔗](#lib:operator/=,path)

`path& operator/=(const path& p);
`

[2](#2)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L14350)

*Effects*: If p.is_absolute() || (p.has_root_name() && p.root_name() != root_name()),
then operator=(p)[.](#2.sentence-1)

[3](#3)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L14355)

Otherwise, modifies *this as if by these steps:

- [(3.1)](#3.1)

  If p.has_root_directory(),
 then removes any root directory and relative path
 from the generic format pathname[.](#3.1.sentence-1)
  Otherwise,
 if !has_root_directory() && is_absolute() is true or if has_filename() is true,
 then appends path​::​preferred_separator to the generic format pathname[.](#3.1.sentence-2)

- [(3.2)](#3.2)

  Then appends the native format pathname of p,
 omitting any [*root-name*](fs.path.generic#nt:root-name "31.12.6.2 Generic pathname format [fs.path.generic]") from its generic format pathname,
 to the native format pathname[.](#3.2.sentence-1)

[4](#4)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L14370)

[*Example [1](#example-1)*:

Even if //host is interpreted as a [*root-name*](fs.path.generic#nt:root-name "31.12.6.2 Generic pathname format [fs.path.generic]"),
both of the paths path("//host")/"foo" and path("//host/")/"foo" equal "//host/foo" (although the former might use backslash as the
preferred separator)[.](#4.sentence-1)

Expression examples:// On POSIX, path("foo") /= path(""); // yields path("foo/") path("foo") /= path("/bar"); // yields path("/bar")// On Windows, path("foo") /= path(""); // yields path("foo\\") path("foo") /= path("/bar"); // yields path("/bar") path("foo") /= path("c:/bar"); // yields path("c:/bar") path("foo") /= path("c:"); // yields path("c:") path("c:") /= path(""); // yields path("c:") path("c:foo") /= path("/bar"); // yields path("c:/bar") path("c:foo") /= path("c:bar"); // yields path("c:foo\\bar")

— *end example*]

[5](#5)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L14394)

*Returns*: *this[.](#5.sentence-1)

[🔗](#lib:operator/=,path_)

`template<class Source>
  path& operator/=(const Source& source);
template<class Source>
  path& append(const Source& source);
`

[6](#6)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L14409)

*Effects*: Equivalent to: return operator/=(path(source));

[🔗](#lib:operator/=,path__)

`template<class InputIterator>
  path& append(InputIterator first, InputIterator last);
`

[7](#7)

[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L14422)

*Effects*: Equivalent to: return operator/=(path(first, last));