std::filesystem::path::string,std::filesystem::path::wstring, (3) - Linux Manuals

std::filesystem::path::string,std::filesystem::path::wstring,: std::filesystem::path::string,std::filesystem::path::wstring,

NAME

std::filesystem::path::string,std::filesystem::path::wstring, - std::filesystem::path::string,std::filesystem::path::wstring,

Synopsis

template< class CharT, class Traits =
std::char_traits<CharT>,
                                                          (since
class Alloc = std::allocator<CharT> >                       (1) C++17)
std::basic_string<CharT,Traits,Alloc>

string( const Alloc& a = Alloc() ) const;
std::string string() const;
std::wstring wstring() const;
std::u16string u16string() const;
std::u32string u32string() const;
                                                      (2) (since       (since
std::string u8string() const;                                   C++17)       C++17)
                                                                  (3)  (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

// Run this code

 #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