NAME

std::experimental::filesystem::u8path - std::experimental::filesystem::u8path

Synopsis

Defined in header <experimental/filesystem>
template< class Source > (1) (filesystem TS)
path u8path( const Source& source );
template< class InputIt > (2) (filesystem TS)
path u8path( InputIt first, InputIt last );

Constructs a path p from a UTF-8 encoded sequence of chars, supplied either as an
std::string, or as a null-terminated multibyte string, or as a [first, last)
iterator pair.

* If path::value_type is char and native encoding is UTF-8, constructs a path
directly as if by path(source) or path(first, last). Note: this is the typical
situation of a POSIX system that uses Unicode, such as Linux.
* Otherwise, if path::value_type is wchar_t and native encoding is UTF-16 (this is
the situation on Windows), or if path::value_type is char16_t (native encoding
guaranteed UTF-16) or char32_t (native encoding guaranteed UTF-32), then first
converts the UTF-8 character sequence to a temporary string tmp of type
path::string_type and then the new path is constructed as if by path(tmp)
* Otherwise (for non-UTF-8 narrow character encodings and for non-UTF-16 wchar_t),
first converts the UTF-8 character sequence to a temporary UTF-32-encoded string
tmp of type std::u32string, and then the new path is constructed as if by
path(tmp) (this path is taken on a POSIX system with a non-Unicode multibyte or
single-byte encoded filesystem)

Parameters

an UTF-8 encoded std::string, pointer to a null-terminated multibyte
source - string, or an input iterator with char value type that points to a
null-terminated multibyte string
first, last - pair of LegacyInputIterators that specify a UTF-8 encoded character
sequence

Type requirements

-
InputIt must meet the requirements of LegacyInputIterator.
-
The value type of InputIt must be char

Return value

The path constructed from the input string after conversion from UTF-8 to the
filesystem's native character encoding.

Exceptions

May throw filesystem_error on underlying OS API errors or std::bad_alloc if memory
allocation fails.

Notes

On systems where native path format differs from the generic path format (neither
Windows nor POSIX systems are examples of such OSes), if the argument to this
function is using generic format, it will be converted to native.

Example

// Run this code

#include <cstdio>
#include <clocale>
#include <fstream>
#include <iostream>
#include <experimental/filesystem>
namespace fs = std::experimental::filesystem;

int main()
{
std::setlocale(LC_ALL, "en_US.utf8");
std::locale::global(std::locale("en_US.utf8"));

fs::path p = fs::u8path(u8"要らない.txt");

// native string representation can be used with OS APIs
std::ofstream(p) << "File contents"; // this uses operator string()
if(std::FILE* f = std::fopen(p.c_str(), "r")) {
int ch;
while((ch=fgetc(f))!= EOF) putchar(ch);
std::fclose(f);
}

// multibyte and wide representation can be used for output
std::cout.imbue(std::locale());
std::cout << "\nFile name in narrow multibyte encoding: "
<< p.string() << '\n';

std::wcerr.imbue(std::locale());
std::wcerr << "File name in wide encoding: "
<< p.wstring() << '\n';

fs::remove(p);
}

Possible output:

File contents
File name in narrow multibyte encoding: 要らない.txt
File name in wide encoding: 要らない.txt