cppdraft_translate/cppdraft/fs/path/construct.md

[fs.path.construct]

31 Input/output library [input.output]

31.12 File systems [filesystems]

31.12.6 Class path [fs.class.path]

31.12.6.5 Members [fs.path.member]

31.12.6.5.1 Constructors [fs.path.construct]

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path() noexcept;

1

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Postconditions: empty() is true.

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

2

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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.

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

3

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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.

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

4

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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.

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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);

5

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Mandates: The value type of Source and InputIterator ischar.

6

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

• (6.1)

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

• (6.2)

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

7

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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 1:

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 usinglatin1_facet to convert ISO/IEC 8859-1 encodedlatin1_string to a wide character string in the native wide encoding ([fs.path.type.cvt]).

The resulting wide string is then converted to an ordinary character pathname string in the current native ordinary encoding.

If the native wide encoding is UTF-16 or UTF-32, and the current native ordinary 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 ordinary 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 encodedlatin1_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]