30 Input/output library [input.output]

30.10 File systems [filesystems]

30.10.7 Class path [fs.class.path] path members [fs.path.member] path 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); path& operator+=(value_type x); template <class Source> path& operator+=(const Source& x); template <class EcharT> path& operator+=(EcharT x); template <class Source> path& concat(const Source& x);
Effects: Appends path(x).native() to the pathname in the native format.
This directly manipulates the value of native() and may not be portable between operating systems.
end note
Returns: *this.
template <class InputIterator> path& concat(InputIterator first, InputIterator last);
Effects: Equivalent to return *this += path(first, last).