30 Input/output library [input.output]

30.10 File systems [filesystems]

30.10.8 Class path [fs.class.path]

30.10.8.6 path non-member functions [fs.path.nonmember]

30.10.8.6.2 path factory functions [fs.path.factory]

template <class Source>
  path u8path(const Source& source);
template <class InputIterator>
  path u8path(InputIterator first, InputIterator last);

Requires: The source and [first, last) sequences are UTF-8 encoded.

The value type of Source and InputIterator is char.

Returns:

(2.1)
If value_type is char and the current native narrow encoding ([fs.def.native.encode]) is UTF-8, return path(source) or path(first, last); otherwise,
(2.2)
if value_type is wchar_t and the native wide encoding is UTF-16, or if value_type is char16_t or char32_t, convert source or [first, last) to a temporary, tmp, of type string_type and return path(tmp); otherwise,
(2.3)
convert source or [first, last) to a temporary, tmp, of type u32string and return path(tmp).

Remarks: Argument format conversion ([fs.path.fmt.cvt]) applies to the arguments for these functions.

How Unicode encoding conversions are performed is unspecified.

[ Example

A string is to be read from a database that is encoded in UTF-8, and used to create a directory using the native encoding for filenames:

namespace fs = std::filesystem;
std::string utf8_string = read_utf8_data();
fs::create_directory(fs::u8path(utf8_string));

For POSIX-based operating systems with the native narrow encoding set to UTF-8, no encoding or type conversion occurs.

For POSIX-based operating systems with the native narrow encoding not set to UTF-8, a conversion to UTF-32 occurs, followed by a conversion to the current native narrow encoding.

Some Unicode characters may have no native character set representation.

For Windows-based operating systems a conversion from UTF-8 to UTF-16 occurs.

— end example

]