std::filesystem:: relative, std::filesystem:: proximate

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Defined in header `<filesystem>`
path relative ( const std:: filesystem :: path & p, std:: error_code & ec ) ;	(1)	(since C++17)
path relative ( const std:: filesystem :: path & p, const std:: filesystem :: path & base = std:: filesystem :: current_path ( ) ) ;	(2)	(since C++17)
path relative ( const std:: filesystem :: path & p, const std:: filesystem :: path & base, std:: error_code & ec ) ;	(3)	(since C++17)
path proximate ( const std:: filesystem :: path & p, std:: error_code & ec ) ;	(4)	(since C++17)
path proximate ( const std:: filesystem :: path & p, const std:: filesystem :: path & base = std:: filesystem :: current_path ( ) ) ;	(5)	(since C++17)
path proximate ( const std:: filesystem :: path & p, const std:: filesystem :: path & base, std:: error_code & ec ) ;	(6)	(since C++17)

1) Returns relative ( p, current_path ( ) , ec ) .

2,3) Returns p made relative to base . Resolves symlinks and normalizes both p and base before other processing. Effectively returns std:: filesystem :: weakly_canonical ( p ) . lexically_relative ( std:: filesystem :: weakly_canonical ( base ) ) or std:: filesystem :: weakly_canonical ( p, ec ) . lexically_relative ( std:: filesystem :: weakly_canonical ( base, ec ) ) , except the error code form returns path ( ) at the first error occurrence, if any.

4) Returns proximate ( p, current_path ( ) , ec ) .

5,6) Effectively returns std:: filesystem :: weakly_canonical ( p ) . lexically_proximate ( std:: filesystem :: weakly_canonical ( base ) ) or std:: filesystem :: weakly_canonical ( p, ec ) . lexically_proximate ( std:: filesystem :: weakly_canonical ( base, ec ) ) , except the error code form returns path ( ) at the first error occurrence, if any.

Parameters

p	-	an existing path
base	-	base path, against which p will be made relative/proximate
ec	-	error code to store error status to

Return value

1) p made relative against current_path ( ) .

2,3) p made relative against base .

4) p made proximate against current_path ( ) .

5,6) p made proximate against base .

Exceptions

Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails.

2,5) Throws std::filesystem::filesystem_error on underlying OS API errors, constructed with p as the first path argument, base as the second path argument, and the OS error code as the error code argument.

1,3,4,6) Sets a std:: error_code & parameter to the OS API error code if an OS API call fails, and executes ec. clear ( ) if no errors occur.

Example

Run this code

#include <filesystem>
#include <iostream>
 
void show(std::filesystem::path x, std::filesystem::path y)
{
    std::cout << "x:\t\t " << x << "\ny:\t\t " << y << '\n'
              << "relative(x, y):  "
              << std::filesystem::relative(x, y) << '\n'
              << "proximate(x, y): "
              << std::filesystem::proximate(x, y) << "\n\n";
}
 
int main()
{
    show("/a/b/c", "/a/b");
    show("/a/c", "/a/b");
    show("c", "/a/b");
    show("/a/b", "c");
}

Possible output:

x:               "/a/b/c"
y:               "/a/b"
relative(x, y):  "c"
proximate(x, y): "c"
 
x:               "/a/c"
y:               "/a/b"
relative(x, y):  "../c"
proximate(x, y): "../c"
 
x:               "c"
y:               "/a/b"
relative(x, y):  ""
proximate(x, y): "c"
 
x:               "/a/b"
y:               "c"
relative(x, y):  ""
proximate(x, y): "/a/b"

Compiler support
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Language
Standard library
Standard library headers
Named requirements
Feature test macros (C++20)
Language support library
Concepts library (C++20)
Metaprogramming library (C++11)
Diagnostics library
General utilities library
Strings library
Containers library
Iterators library
Ranges library (C++20)
Algorithms library
Numerics library
Localizations library
Input/output library
Filesystem library (C++17)
Regular expressions library (C++11)
Concurrency support library (C++11)
Execution support library (C++26)
Technical specifications
Symbols index
External libraries

path (C++17)	represents a path (class)
absolute (C++17)	composes an absolute path (function)
canonical weakly_canonical (C++17)	composes a canonical path (function)
lexically_normal lexically_relative lexically_proximate	converts path to normal form converts path to relative form converts path to proximate form (public member function of `std::filesystem::path` )

std::filesystem:: relative, std::filesystem:: proximate

Parameters

Return value

Exceptions

Example

See also

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