std::filesystem::rename
| Defined in header <filesystem>
|
||
| void rename( const std::filesystem::path& old_p, const std::filesystem::path& new_p ); |
(since C++17) | |
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
#include <filesystem> #include <fstream> namespace fs = std::filesystem; int main() { std::filesystem::path p = std::filesystem::current_path() / "sandbox"; std::filesystem::create_directories(p / "from"); std::ofstream{ p / "from/file1.txt" }.put('a'); std::filesystem::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 std::filesystem::remove_all(p); }
See also
| renames a file (function) | |
| (C++17)(C++17) |
removes a file or empty directory removes a file or directory and all its contents, recursively (function) |