NAME¶

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

Synopsis¶

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

const std::filesystem::path& base, (3) (since C++17)

std::error_code& ec );
path proximate( const std::filesystem::path& p, (4) (since C++17)
std::error_code& ec );
path proximate( const std::filesystem::path& p,
const std::filesystem::path& base = (5) (since C++17)
std::filesystem::current_path() );
path proximate( const std::filesystem::path& p,

const std::filesystem::path& base, (6) (since C++17)

std::error_code& ec );

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"

See also¶

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