std::filesystem::path::path (3) - Linux Manuals

std::filesystem::path::path: std::filesystem::path::path

NAME

std::filesystem::path::path - std::filesystem::path::path

Synopsis

path() noexcept; (1) (since C++17)
path( const path& p ); (2) (since C++17)
path( path&& p ) noexcept; (3) (since C++17)
path( string_type&& source, format fmt = auto_format ); (4) (since C++17)
template< class Source > (5) (since C++17)
path( const Source& source, format fmt = auto_format );
template< class InputIt > (6) (since C++17)
path( InputIt first, InputIt last, format fmt = auto_format );
template< class Source > (7) (since C++17)
path( const Source& source, const std::locale& loc, format fmt = auto_format );
template< class InputIt > (8) (since C++17)
path( InputIt first, InputIt last, const std::locale& loc, format fmt = auto_format );

Constructs a new path object.
1) Constructs an empty path.
2) Copy constructor. Constructs a path whose pathname, in both native and generic formats, is the same as that of p
3) Move constructor. Constructs a path whose pathname, in both native and generic formats, is the same as that of p, p is left in valid but unspecified state.
4-6) Constructs the path from a character sequence (format interpreted as specified by fmt) provided by source (4,5), which is a pointer or an input iterator to a null-terminated character/wide character sequence, an std::basic_string or an std::basic_string_view, or represented as a pair of input iterators [first, last) (6). Any of the character types char,
char8_t,
(since C++20)char16_t, char32_t, wchar_t is allowed, and the method of conversion to the native character set depends on the character type used by source

      * If the source character type is char, the encoding of the source is assumed to be the native narrow encoding (so no conversion takes place on POSIX systems)

      * If the source character type is char8_t, conversion from UTF-8 to native filesystem encoding is used. (since C++20)

      * If the source character type is char16_t, conversion from UTF-16 to native filesystem encoding is used.
      * If the source character type is char32_t, conversion from UTF-32 to native filesystem encoding is used.
      * If the source character type is wchar_t, the input is assumed to be the native wide encoding (so no conversion takes places on Windows)

7-8) Constructs the path from a character sequence (format interpreted as specified by fmt) provided by source (6), which is a pointer or an input iterator to a null-terminated character sequence, an std::string, an std::basic_string_view, or represented as a pair of input iterators [first, last) ((7)). The only character type allowed is char. Uses loc to perform the character encoding conversion. If value_type is wchar_t, converts from to wide using the std::codecvt<wchar_t, char, std::mbstate_t> facet of loc. Otherwise, first converts to wide using the std::codecvt<wchar_t, char, std::mbstate_t> facet and then converts to filesystem native character type using std::codecvt<wchar_t,value_type> facet of loc.

Parameters

p - a path to copy
source - std::basic_string, std::basic_string_view, pointer to a null-terminated character string, or input iterator with a character value type that points to a null-terminated character sequence (the character type must be char for overload (6))
first, last - pair of LegacyInputIterators that specify a character sequence
fmt - enumerator of type path::format which specifies how pathname format is to be interpreted
loc - locale that defines encoding conversion to use

Type requirements

-
InputIt must meet the requirements of LegacyInputIterator.
-
The value type of InputIt must be one of the character types char, wchar_t,
char8_t,
(since C++20)char16_t and char32_t to use the overload (5))
-
The value type of InputIt must be char to use the overload (7))

Exceptions

2, 4-8) (none)

Notes

For portable pathname generation from Unicode strings, see u8path. (until C++20)
path constructor supports creation from UTF-8 string when the source is a sequence of char8_t. (since C++20)

Example

// Run this code

  #include <iostream>
  #include <filesystem>
  namespace fs = std::filesystem;
  int main()
  {
      fs::path p1 = "/usr/lib/sendmail.cf"; // portable format
      fs::path p2 = "C:\\users\\abcdef\\AppData\\Local\\Temp\\"; // native format
      fs::path p3 = L"D:/猫.txt"; // wide string

      std::cout << "p1 = " << p1 << '\n'
                << "p2 = " << p2 << '\n'
                << "p3 = " << p3 << '\n';
  }

Output:

  p1 = "/usr/lib/sendmail.cf"
  p2 = "C:\users\abcdef\AppData\Local\Temp\"
  p3 = "D:/猫.txt"