std::filesystem::create_symlink, std::filesystem::create_directory_symlink

 

C++

Compiler support

Freestanding and hosted

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)

Technical specifications

Symbols index

External libraries

 

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>
void create_symlink( const std::filesystem::path& target,                      const std::filesystem::path& link ); void create_symlink( const std::filesystem::path& target,                      const std::filesystem::path& link,                      std::error_code& ec ) noexcept;	(1)	(since C++17)
void create_directory_symlink( const std::filesystem::path& target,                                const std::filesystem::path& link ); void create_directory_symlink( const std::filesystem::path& target,                                const std::filesystem::path& link,                                std::error_code& ec ) noexcept;	(2)	(since C++17)

Creates a symbolic link link with its target set to target as if by POSIX symlink(): the pathname target may be invalid or non-existing.

Some operating systems require symlink creation to identify that the link is to a directory. Portable code should use (2) to create directory symlinks rather than (1), even though there is no distinction on POSIX systems.

Parameters

target	-	path to point the symlink to, does not have to exist
link	-	path of the new symbolic link
ec	-	out-parameter for error reporting in the non-throwing overload

Return value

(none)

Exceptions

The overload that does not take a std::error_code& parameter throws filesystem::filesystem_error on underlying OS API errors, constructed with target as the first path argument, link 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.

Notes

Some operating systems do not support symbolic links at all or support them only for regular files.

Some file systems do not support symbolic links regardless of the operating system, for example the FAT system used on some memory cards and flash drives.

Like a hard link, a symbolic link allows a file to have multiple logical names. The presence of a hard link guarantees the existence of a file, even after the original name has been removed. A symbolic link provides no such assurance; in fact, the file named by the target argument need not exist when the link is created. A symbolic link can cross file system boundaries.

Example

Run this code

#include <iostream>
#include <filesystem>
#include <cassert>
namespace fs = std::filesystem;
 
int main()
{
    fs::create_directories("sandbox/subdir");
    fs::create_symlink("target", "sandbox/sym1");
    fs::create_directory_symlink("subdir", "sandbox/sym2");
 
    for(auto it = fs::directory_iterator("sandbox"); it != fs::directory_iterator(); ++it)
        if(is_symlink(it->symlink_status()))
            std::cout << *it << "->" << read_symlink(*it) << '\n';
 
    assert( std::filesystem::equivalent("sandbox/sym2", "sandbox/subdir") );
    fs::remove_all("sandbox");
}

Possible output:

"sandbox/sym1"->"target"
"sandbox/sym2"->"subdir"

See also

statussymlink_status (C++17)(C++17)	determines file attributes determines file attributes, checking the symlink target (function)
read_symlink (C++17)	obtains the target of a symbolic link (function)
create_hard_link (C++17)	creates a hard link (function)