NAME¶

std::filesystem::rename - std::filesystem::rename

Synopsis¶

Defined in header <filesystem>
void rename(const std::filesystem::path& old_p,

const std::filesystem::path& new_p);
void rename(const std::filesystem::path& old_p, (since C++17)
const std::filesystem::path& new_p,

std::error_code& ec) noexcept;

Moves or renames the filesystem object identified by old_p to new_p as if by the
POSIX rename:

* If old_p is a non-directory file, then new_p must be one of:

* the same file as old_p or a hardlink to it: nothing is done in this
case
* existing non-directory file: new_p is first deleted, then, without
allowing other processes to observe new_p as deleted, the pathname
new_p is linked to the file and old_p is unlinked from the file. Write
permissions are required to both the directory that contains old_p and
the directory that contains new_p.
* non-existing file in an existing directory: The pathname new_p is
linked to the file and old_p is unlinked from the file. Write
permissions are required to both the directory that contains old_p and
the directory that contains new_p.

* If old_p is a directory, then new_p must be one of:

* the same directory as old_p or a hardlink to it: nothing is done in
this case
* existing directory: new_p is deleted if empty on POSIX systems, but
this may be an error on other systems. If not an error, then new_p is
first deleted, then, without allowing other processes to observe new_p
as deleted, the pathname new_p is linked to the directory and old_p is
unlinked from the directory. Write permissions are required to both the
directory that contains old_p and the directory that contains new_p.
* non-existing directory, not ending with a directory separator, and
whose parent directory exists: The pathname new_p is linked to the
directory and old_p is unlinked from the directory. Write permissions
are required to both the directory that contains old_p and the
directory that contains new_p.

* Symlinks are not followed: if old_p is a symlink, it is itself renamed, not its
target. If new_p is an existing symlink, it is itself erased, not its target.

Rename fails if

* new_p ends with dot or with dot-dot
* new_p names a non-existing directory ending with a directory separator
* old_p is a directory which is an ancestor of new_p

Parameters¶

old_p - path to move or rename
new_p - target path for the move/rename operation
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 old_p as
the first path argument, new_p 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¶

// Run this code

#include <iostream>
#include <fstream>
#include <filesystem>
namespace fs = std::filesystem;
int main()
{
fs::path p = fs::current_path() / "sandbox";
fs::create_directories(p/"from");
std::ofstream(p/"from/file1.txt").put('a');
fs::create_directory(p/"to");

// fs::rename(p/"from/file1.txt", p/"to/"); // error: to is a directory
fs::rename(p/"from/file1.txt", p/"to/file2.txt"); // OK
// fs::rename(p/"from", p/"to"); // error: to is not empty
fs::rename(p/"from", p/"to/subdir"); // OK

fs::remove_all(p);
}

See also¶

rename renames a file
(function)
remove removes a file or empty directory
remove_all removes a file or directory and all its contents, recursively
(C++17) (function)
(C++17)