31 Input/output library [input.output]

31.12 File systems [filesystems]

31.12.13 Filesystem operation functions [fs.op.funcs]

31.12.13.36 Status [fs.op.status]

file_status filesystem::status(const path& p);

Effects: As if by: error_code ec; file_status result = status(p, ec); if (result.type() == file_type::none) throw filesystem_error(implementation-supplied-message, p, ec); return result;

Returns: See above.

Throws: filesystem_error.

[Note 1:

result values of file_status(file_type::not_found) and file_status(file_type::unknown) are not considered failures and do not cause an exception to be thrown.

— end note]

🔗

file_status filesystem::status(const path& p, error_code& ec) noexcept;

Effects: If possible, determines the attributes of the file p resolves to, as if by using POSIX stat() to obtain a POSIX struct stat.

If, during attribute determination, the underlying file system API reports an error, sets ec to indicate the specific error reported.

Otherwise, ec.clear().

[Note 2:

This allows users to inspect the specifics of underlying API errors even when the value returned by status() is not file_status(file_type::none).

— end note]

Let prms denote the result of (m & perms::mask), where m is determined as if by converting the st_mode member of the obtained struct stat to the type perms.

Returns:

(6.1)
If ec != error_code():
- (6.1.1)
  If the specific error indicates that p cannot be resolved because some element of the path does not exist, returns file_status(file_type::not_found).
- (6.1.2)
  Otherwise, if the specific error indicates that p can be resolved but the attributes cannot be determined, returns file_status(file_type::unknown).
- (6.1.3)
  Otherwise, returns file_status(file_type::none).
[Note 3:
These semantics distinguish between p being known not to exist, p existing but not being able to determine its attributes, and there being an error that prevents even knowing if p exists.

These distinctions are important to some use cases.
— end note]
(6.2)
Otherwise,
- (6.2.1)
  If the attributes indicate a regular file, as if by POSIX S_ISREG, returns file_status(file_type::regular, prms).
  
  [Note 4:
  file_type::regular implies appropriate <fstream> operations would succeed, assuming no hardware, permission, access, or file system race errors.
  
  Lack of file_type::regular does not necessarily imply <fstream> operations would fail on a directory.
  — end note]
- (6.2.2)
  Otherwise, if the attributes indicate a directory, as if by POSIX S_ISDIR, returns file_status(file_type::directory, prms).
  
  [Note 5:
  file_type::directory implies that calling directory_iterator(p) would succeed.
  — end note]
- (6.2.3)
  Otherwise, if the attributes indicate a block special file, as if by POSIX S_ISBLK, returns file_status(file_type::block, prms).
- (6.2.4)
  Otherwise, if the attributes indicate a character special file, as if by POSIX S_ISCHR, returns file_status(file_type::character, prms).
- (6.2.5)
  Otherwise, if the attributes indicate a fifo or pipe file, as if by POSIX S_ISFIFO, returns file_status(file_type::fifo, prms).
- (6.2.6)
  Otherwise, if the attributes indicate a socket, as if by POSIX S_ISSOCK, returns file_status(file_type::socket, prms).
- (6.2.7)
  Otherwise, if the attributes indicate an implementation-defined file type ([fs.enum.file.type]), returns file_status(file_type::A, prms), where A is the constant for the implementation-defined file type.
- (6.2.8)
  Otherwise, returns file_status(file_type::unknown, prms).

Remarks: If a symbolic link is encountered during pathname resolution, pathname resolution continues using the contents of the symbolic link.