29 Input/output library [input.output]

29.12 File systems [filesystems]

29.12.6 Class path [fs.class.path]

29.12.6.5 Members [fs.path.member]

29.12.6.5.4 Concatenation [fs.path.concat]

path& operator+=(const path& x); path& operator+=(const string_type& x); path& operator+=(basic_string_view<value_type> x); path& operator+=(const value_type* x); template<class Source> path& operator+=(const Source& x); template<class Source> path& concat(const Source& x);
Effects: Appends path(x).native() to the pathname in the native format.
[Note 1:
This directly manipulates the value of native(), which is not necessarily portable between operating systems.
— end note]
Returns: *this.
path& operator+=(value_type x); template<class EcharT> path& operator+=(EcharT x);
Effects: Equivalent to: return *this += basic_­string_­view(&x, 1);
template<class InputIterator> path& concat(InputIterator first, InputIterator last);
Effects: Equivalent to: return *this += path(first, last);