std::filesystem::path::string, std::filesystem::path::wstring, std::filesystem::path::u8string, std::filesystem::path::u16string, std::filesystem::path::u32string

template< class CharT, class Traits = std::char_traits<CharT>,
          class Alloc = std::allocator<CharT> >
std::basic_string<CharT,Traits,Alloc>
    string( const Alloc& a = Alloc() ) const;
 (1) (since C++17)
(2) (since C++17) 
std::string string() const;
 
std::wstring wstring() const;
 
std::u16string u16string() const;
 
std::u32string u32string() const;
(3) 
std::string u8string() const;
 (since C++17)
(until C++20) 
std::u8string u8string() const;
 (since C++20)

Returns the internal pathname in native pathname format, converted to specific string type. Conversion, if any, is performed as follows:

  • If path::value_type is char, conversion, if any, is system-dependent. This is the case on typical POSIX systems (such as Linux), where native encoding is UTF-8 and string() performs no conversion.
  • Otherwise, if path::value_type is wchar_t, conversion, if any, is unspecified. This is the case on Windows, where wchar_t is 16 bit and the native encoding is UTF-16.
  • Otherwise, if path::value_type is char16_t, native encoding is UTF-16 and the conversion method is unspecified.
  • Otherwise, if path::value_type is char32_t, native encoding is UTF-32 and the conversion method is unspecified.
  • Otherwise, if path::value_type is char8_t, native encoding is UTF-8 and the conversion method is unspecified.
1) All memory allocations are performed by a.
3) The result encoding in the case of u8string() is always UTF-8.

Parameters

(none).

Return value

The internal pathname in native pathname format, converted to specified string type.

Exceptions

(none).

Example

#include <cstdio>
#ifdef _MSC_VER
#include <io.h>
#include <fcntl.h>
#else
#include <locale>
#include <clocale>
#endif
#include <fstream>
#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
 
int main()
{
#ifdef _MSC_VER
    _setmode(_fileno(stderr), _O_WTEXT);
#else
    std::setlocale(LC_ALL, "");
    std::locale::global(std::locale(""));
    std::cout.imbue(std::locale());
    std::wcerr.imbue(std::locale());
#endif
 
    fs::path p = fs::u8path(u8"要らない.txt");
    std::ofstream(p) << "File contents"; // Prior to LWG2676 uses operator string_type()
                                         // on MSVC, where string_type is wstring, only
                                         // works due to non-standard extension.
                                         // Post-LWG2676 uses new fstream constructors
 
    // native string representation can be used with OS APIs
    if (std::FILE* f =
#ifdef _MSC_VER
                _wfopen(p.c_str(), L"r")
#else
                std::fopen(p.c_str(), "r")
#endif
        )
    {
        int ch;
        while((ch=fgetc(f))!= EOF) putchar(ch);
        std::fclose(f);
    }
 
    // multibyte and wide representation can be used for output
    std::cout << "\nFile name in narrow multibyte encoding: " << p.string() << '\n';
    std::wcerr << "File name in wide encoding: " << p.wstring() << '\n';
 
    fs::remove(p);
}

Output:

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

See also

returns the path in generic pathname format converted to a string
(public member function)

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