std::filesystem::absolute

 

C++

Language

Standard library headers

Concepts

Utilities library

Strings library

Containers library

Algorithms library

Iterators library

Numerics library

Input/output library

Localizations library

Regular expressions library (C++11)

Atomic operations library (C++11)

Thread support library (C++11)

Filesystem library (C++17)

Technical Specifications

 

Filesystem library

Classes
filesystem::path filesystem::filesystem_error filesystem::directory_entry filesystem::directory_iterator filesystem::recursive_directory_iterator filesystem::file_status	filesystem::space_info filesystem::file_type filesystem::perms filesystem::perm_options filesystem::copy_options filesystem::directory_options filesystem::file_time_type
Functions
filesystem::absolute filesystem::canonicalfilesystem::weakly_canonical filesystem::relativefilesystem::proximate filesystem::copy filesystem::copy_file filesystem::copy_symlink filesystem::create_directory filesystem::create_directories filesystem::create_hard_link filesystem::create_symlink filesystem::create_directory_symlink filesystem::current_path	filesystem::exists filesystem::equivalent filesystem::file_size filesystem::hard_link_count filesystem::last_write_time filesystem::permissions filesystem::read_symlink filesystem::remove filesystem::remove_all filesystem::rename filesystem::resize_file filesystem::space filesystem::status filesystem::symlink_status filesystem::temp_directory_path
File types
filesystem::is_block_file filesystem::is_character_file filesystem::is_directory filesystem::is_empty filesystem::status_known	filesystem::is_fifo filesystem::is_other filesystem::is_regular_file filesystem::is_socket filesystem::is_symlink

 

Defined in header <filesystem>
path absolute(const std::filesystem::path& p); path absolute(const std::filesystem::path& p, std::error_code& ec);	(1)	(since C++17)

1) Returns a path referencing the same file system location as p, for which 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_error on underlying OS API errors, constructed with p as the first argument and the OS error code as the error code argument. std::bad_alloc may be thrown if memory allocation fails. 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.

Notes

It is not an error if absolute results in a path that refers to a non-existent file. In particular, on systems that support root names (e.g. Windows), the result of calling absolute on a relative path that has a root name (e.g. "D:file.txt" when the current working directory is on a different root name, will usually result in a non-existent path.

For POSIX-based operating systems, std::filesystem::absolute(p) is equivalent to std::filesystem::current_path() / p

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

Example

Run this code

#include <iostream>
#include <filesystem>
namespace fs = std::filesystem;
int main()
{
    fs::path p = "C:cl.exe";
    std::cout << "Current path is " << fs::current_path() << '\n'
              << "Absolute path for " << p << " is " << fs::absolute(p) << '\n';
// actual location: "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\cl.exe"
}

Possible output:

Current path is "D:/local/ConsoleApplication1"
Absolute path for "C:cl.exe" is "C:/local/ConsoleApplication1/cl.exe"

See also

canonicalweakly_canonical (C++17)	composes a canonical path (function)
relativeproximate (C++17)	composes a relative path (function)