std::filesystem::relative, std::filesystem::proximate
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());
path relative( const std::filesystem::path& p,
const std::filesystem::path& base,
std::error_code& ec ); |
(2) | (since C++17) |
path proximate( const std::filesystem::path& p,
std::error_code& ec ); |
(3) | (since C++17) |
path proximate( const std::filesystem::path& p,
const std::filesystem::path& base = std::filesystem::current_path());
path proximate( const std::filesystem::path& p,
const std::filesystem::path& base,
std::error_code& ec ); |
(4) | (since C++17) |
1) Returns
relative(p, current_path(), ec)
2) 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.
3) Returns
proximate(p, current_path(), ec)
4) 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 base.
2) p made proximate against base
Exceptions
The overload that does not take a std::error_code& parameter throws 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. The overload taking a std::error_code& parameter sets it to the OS API error code if an OS API call fails, and executes ec.clear() if no errors occur. Any overload not marked noexcept may throw std::bad_alloc if memory allocation fails.
Example
#include <iostream>
#include <filesystem>
void show(std::filesystem::path a, std::filesystem::path b)
{
std::cout << "relative (" << a << "," << b << ") == ";
std::cout << std::filesystem::relative(a,b) << "\n";
std::cout << "proximate(" << a << "," << b << ") == ";
std::cout << std::filesystem::proximate(a,b) << "\n";
}
int main()
{
show("/a/b/c","/a/b");
show("/a/c","/a/b");
show("c","/a/b");
show("/a/b","c");
}
Possible output:
relative ("/a/b/c","/a/b") == "c"
proximate("/a/b/c","/a/b") == "c"
relative ("/a/c","/a/b") == "../c"
proximate("/a/c","/a/b") == "../c"
relative ("c","/a/b") == ""
proximate("c","/a/b") == "c"
relative ("/a/b","c") == ""
proximate("/a/b","c") == "/a/b"
See also
|
(C++17)
|
represents a path (class) |
|
(C++17)
|
composes an absolute path (function) |
|
(C++17)
|
composes a canonical path (function) |
| converts path to normal form converts path to relative form converts path to proximate form (public member function of std::filesystem::path) |
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