std::experimental::filesystem::create_symlink, (3) - Linux Man Pages

std::experimental::filesystem::create_symlink,: std::experimental::filesystem::create_symlink,

NAME

std::experimental::filesystem::create_symlink, - std::experimental::filesystem::create_symlink,

Synopsis


Defined in header <experimental/filesystem>
void create_symlink( const path& target, const path& link );
void create_symlink( const path& target, const path& link,       (1) (filesystem TS)
error_code& ec );
void create_directory_symlink( const path& target, const path&
link );                                                          (2) (filesystem TS)
void create_directory_symlink( const path& target, const path&
link, error_code& ec );


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 error_code& parameter throws filesystem_error on
underlying OS API errors, constructed with target as the first argument, link as the
second 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 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. This overload has
noexcept specification:
noexcept

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 <experimental/filesystem>
 namespace fs std::experimental::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';


  fs::remove_all("sandbox");
 }

Possible output:


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

See also


status           determines file attributes
symlink_status   determines file attributes, checking the symlink target
           (function)
read_symlink     obtains the target of a symbolic link
           (function)
create_hard_link creates a hard link
           (function)