30 Input/output library [input.output]

30.10 File systems [filesystems]

30.10.8 Class path [fs.class.path]

30.10.8.4 path members [fs.path.member]

30.10.8.4.1 path constructors [fs.path.construct]

path() noexcept;

Effects: Constructs an object of class path.

Postconditions: empty() == true.

path(const path& p); path(path&& p) noexcept;

Effects: Constructs an object of class path having the same pathname in the native and generic formats, respectively, as the original value of p. In the second form, p is left in a valid but unspecified state.

path(string_type&& source, format fmt = auto_format);

Effects: Constructs an object of class path for which the pathname in the detected-format of source has the original value of source ([fs.path.fmt.cvt]), converting format if required ([fs.path.fmt.cvt]). source is left in a valid but unspecified state.

template <class Source> path(const Source& source, format fmt = auto_format); template <class InputIterator> path(InputIterator first, InputIterator last, format fmt = auto_format);

Effects: Let s be the effective range of source ([fs.path.req]) or the range [first, last), with the encoding converted if required ([fs.path.cvt]). Finds the detected-format of s ([fs.path.fmt.cvt]) and constructs an object of class path for which the pathname in that format is s.

template <class Source> path(const Source& source, const locale& loc, format fmt = auto_format); template <class InputIterator> path(InputIterator first, InputIterator last, const locale& loc, format fmt = auto_format);

Requires: The value type of Source and InputIterator is char.

Effects: Let s be the effective range of source or the range [first, last), after converting the encoding as follows:

  • If value_­type is wchar_­t, converts to the native wide encoding ([fs.def.native.encode]) using the codecvt<​wchar_­t, char, mbstate_­t> facet of loc.

  • Otherwise a conversion is performed using the codecvt<wchar_­t, char, mbstate_­t> facet of loc, and then a second conversion to the current narrow encoding.

Finds the detected-format of s ([fs.path.fmt.cvt]) and constructs an object of class path for which the pathname in that format is s.

[Example: A string is to be read from a database that is encoded in ISO/IEC 8859-1, and used to create a directory:

namespace fs = std::filesystem;
std::string latin1_string = read_latin1_data();
codecvt_8859_1<wchar_t> latin1_facet;
std::locale latin1_locale(std::locale(), latin1_facet);
fs::create_directory(fs::path(latin1_string, latin1_locale));

For POSIX-based operating systems, the path is constructed by first using latin1_­facet to convert ISO/IEC 8859-1 encoded latin1_­string to a wide character string in the native wide encoding ([fs.def.native.encode]). The resulting wide string is then converted to a narrow character pathname string in the current native narrow encoding. If the native wide encoding is UTF-16 or UTF-32, and the current native narrow encoding is UTF-8, all of the characters in the ISO/IEC 8859-1 character set will be converted to their Unicode representation, but for other native narrow encodings some characters may have no representation.

For Windows-based operating systems, the path is constructed by using latin1_­facet to convert ISO/IEC 8859-1 encoded latin1_­string to a UTF-16 encoded wide character pathname string. All of the characters in the ISO/IEC 8859-1 character set will be converted to their Unicode representation. end example]