std::filesystem::path:: path

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C++
Filesystem library
Classes
Functions
File types
std::filesystem::path
Constants
Member functions
Path decomposition
Non-member functions
(until C++20) (until C++20) (until C++20) (until C++20) (until C++20) (C++20)
Helper Classes
(C++26)
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 >
path ( const Source & source, format fmt = auto_format ) ;
(5) (since C++17)
template < class InputIt >
path ( InputIt first, InputIt last, format fmt = auto_format ) ;
(6) (since C++17)
template < class Source >
path ( const Source & source, const std:: locale & loc, format fmt = auto_format ) ;
(7) (since C++17)
template < class InputIt >
path ( InputIt first, InputIt last, const std:: locale & loc, format fmt = auto_format ) ;
(8) (since C++17)

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 (7) , which is a pointer or an input iterator to a null-terminated character sequence, an std::string , an std::string_view , or represented as a pair of input iterators [ first , last ) (8) . 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 .

(5) and (7) participate in overload resolution only if Source and path are not the same type, and either:

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 (7) )
first, last - pair of LegacyInputIterator s 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 (6) .
-
The value type of InputIt must be char to use the overload (8) .

Exceptions

2,4-8) May throw implementation-defined exceptions.

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 <filesystem>
#include <iostream>
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 = U"D:/猫.txt"; // UTF-32 string
    fs::path p4 = u8"~/狗.txt"; // UTF-8 string
 
    std::cout << "p1 = " << p1 << '\n'
              << "p2 = " << p2 << '\n'
              << "p3 = " << p3 << '\n'
              << "p4 = " << p4 << '\n';
}

Output: 

p1 = "/usr/lib/sendmail.cf"
p2 = "C:\\users\\abcdef\\AppData\\Local\\Temp\\"
p3 = "D:/猫.txt"
p4 = "~/狗.txt"

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 3244 C++17 constraint that Source cannot be path was missing added

See also

(C++17) (deprecated in C++20)
creates a path from a UTF-8 encoded source
(function)
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