NAME¶

std::filesystem::absolute - std::filesystem::absolute

Synopsis¶

Defined in header <filesystem>
path absolute(const std::filesystem::path& p); (since C++17)
path absolute(const std::filesystem::path& p, std::error_code& ec);

Returns a path referencing the same file system location as p, for which
filesystem::is_absolute() is true. The non-throwing overload returns
default-constructed path if an error occurs.

Parameters¶

p - path to convert to absolute form
ec - out-parameter for error reporting in the non-throwing overload.

Return value¶

Returns an absolute (although not necessarily canonical) pathname referencing the
same file as p.

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 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.

Notes¶

Implementations are encouraged to not consider p not existing to be an error.

For POSIX-based operating systems, std::filesystem::absolute(p) is equivalent to
std::filesystem::current_path() / p except for when p is the empty path.

For Windows, std::filesystem::absolute may be implemented as a call to
GetFullPathNameW.

Example¶

// Run this code

#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main()
{
std::filesystem::path p = "foo.c";
std::cout << "Current path is " << fs::current_path() << '\n';
std::cout << "Absolute path for " << p << " is "
<< std::filesystem::absolute(p) << '\n';
}

Possible output:¶

Current path is "/tmp/1622355667.5363104"
Absolute path for "foo.c" is "/tmp/1622355667.5363104/foo.c"

See also¶

canonical composes a canonical path
weakly_canonical (function)
(C++17)
relative composes a relative path
proximate (function)
(C++17)