29 Input/output library [input.output]

29.11 File systems [filesystems]

29.11.14 Filesystem operation functions [fs.op.funcs]

29.11.14.4 Copy file [fs.op.copy.file]

bool copy_file(const path& from, const path& to);
bool copy_file(const path& from, const path& to, error_code& ec);

Returns: copy_file(from, to, copy_options::none) or

copy_file(from, to, copy_options::none, ec), respectively.

Throws: As specified in [fs.err.report].

🔗

bool copy_file(const path& from, const path& to, copy_options options);
bool copy_file(const path& from, const path& to, copy_options options,
               error_code& ec);

Preconditions: At most one element from each option group ([fs.enum.copy.opts]) is set in options.

Effects: As follows:

(4.1)
Report an error as specified in [fs.err.report] if:
- (4.1.1)
  is_regular_file(from) is false, or
- (4.1.2)
  exists(to) is true and is_regular_file(to) is false, or
- (4.1.3)
  exists(to) is true and equivalent(from, to) is true, or
- (4.1.4)
  exists(to) is true and
```
(options & (copy_options::skip_existing |
            copy_options::overwrite_existing |
            copy_options::update_existing)) == copy_options::none
```
(4.2)
Otherwise, copy the contents and attributes of the file from resolves to, to the file to resolves to, if:
- (4.2.1)
  exists(to) is false, or
- (4.2.2)
  (options & copy_options::overwrite_existing) != copy_options::none, or
- (4.2.3)
  (options & copy_options::update_existing) != copy_options::none and from is more recent than to, determined as if by use of the last_write_time function ([fs.op.last.write.time]).
(4.3)
Otherwise, no effects.

Returns: true if the from file was copied, otherwise false.

The signature with argument ec returns false if an error occurs.

Throws: As specified in [fs.err.report].

Complexity: At most one direct or indirect invocation of status(to).