namespace std::filesystem { class recursive_directory_iterator { public: using iterator_category = input_iterator_tag; using value_type = directory_entry; using difference_type = ptrdiff_t; using pointer = const directory_entry*; using reference = const directory_entry&; recursive_directory_iterator() noexcept; explicit recursive_directory_iterator(const path& p); recursive_directory_iterator(const path& p, directory_options options); recursive_directory_iterator(const path& p, directory_options options, error_code& ec); recursive_directory_iterator(const path& p, error_code& ec); recursive_directory_iterator(const recursive_directory_iterator& rhs); recursive_directory_iterator(recursive_directory_iterator&& rhs) noexcept; ~recursive_directory_iterator(); directory_options options() const; int depth() const; bool recursion_pending() const; const directory_entry& operator*() const; const directory_entry* operator->() const; recursive_directory_iterator& operator=(const recursive_directory_iterator& rhs); recursive_directory_iterator& operator=(recursive_directory_iterator&& rhs) noexcept; recursive_directory_iterator& operator++(); recursive_directory_iterator& increment(error_code& ec); void pop(); void pop(error_code& ec); void disable_recursion_pending(); bool operator==(default_sentinel_t) const noexcept { return *this == recursive_directory_iterator(); } }; }

Calling options, depth, recursion_pending, pop or disable_recursion_pending on an iterator that is not dereferenceable results in undefined behavior.

The behavior of a recursive_directory_iterator is the same as a directory_iterator unless otherwise specified.

[Note 1:

If the directory structure being iterated over contains cycles then it is possible that the end iterator is unreachable.

— end note]

recursive_directory_iterator() noexcept;

Effects: Constructs the end iterator.

explicit recursive_directory_iterator(const path& p); recursive_directory_iterator(const path& p, directory_options options); recursive_directory_iterator(const path& p, directory_options options, error_code& ec); recursive_directory_iterator(const path& p, error_code& ec);

Effects: Constructs an iterator representing the first entry in the directory to which p resolves, if any; otherwise, the end iterator.

However, if (options & directory_options::skip_permission_denied) != directory_options::none and construction encounters an error indicating that permission to access p is denied, constructs the end iterator and does not report an error.

Postconditions: options() == options for the signatures with a directory_options argument, otherwise options() == directory_options​::​none.

[Note 1:

Use recursive_directory_iterator(".") rather than recursive_directory_iterator("") to iterate over the current directory.

— end note]

[Note 2:

By default, recursive_directory_iterator does not follow directory symlinks.

To follow directory symlinks, specify options as directory_options​::​follow_directory_symlink.

— end note]

recursive_directory_iterator(const recursive_directory_iterator& rhs);

Postconditions:

• options() == rhs.options()
• depth() == rhs.depth()
• recursion_pending() == rhs.recursion_pending()

recursive_directory_iterator(recursive_directory_iterator&& rhs) noexcept;

Postconditions: options(), depth(), and recursion_pending() have the values that rhs.options(), rhs.depth(), and rhs.recursion_pending(), respectively, had before the function call.

recursive_directory_iterator& operator=(const recursive_directory_iterator& rhs);

Effects: If *this and rhs are the same object, the member has no effect.

Postconditions:

• options() == rhs.options()
• depth() == rhs.depth()
• recursion_pending() == rhs.recursion_pending()

recursive_directory_iterator& operator=(recursive_directory_iterator&& rhs) noexcept;

Effects: If *this and rhs are the same object, the member has no effect.

Postconditions: options(), depth(), and recursion_pending() have the values that rhs.options(), rhs.depth(), and rhs.recursion_pending(), respectively, had before the function call.

directory_options options() const;

Returns: The value of the argument passed to the constructor for the options parameter, if present, otherwise directory_options​::​none.

Returns: The current depth of the directory tree being traversed.

bool recursion_pending() const;

Returns: true if disable_recursion_pending() has not been called subsequent to the prior construction or increment operation, otherwise false.

recursive_directory_iterator& operator++(); recursive_directory_iterator& increment(error_code& ec);

Effects: As specified for the prefix increment operation of Input iterators, except that:

• If there are no more entries at the current depth, then if depth() != 0 iteration over the parent directory resumes; otherwise *this = recursive_directory_iterator().
• Otherwise if recursion_pending() && is_directory((*this)->status()) && (!is_symlink((*this)->symlink_status()) || (options() & directory_options::follow_directory_symlink) != directory_options::none) then either directory (*this)->path() is recursively iterated into or, if (options() & directory_options::skip_permission_denied) != directory_options::none and an error occurs indicating that permission to access directory (*this)->path() is denied, then directory (*this)->path() is treated as an empty directory and no error is reported.

void pop(); void pop(error_code& ec);

Effects: If depth() == 0, set *this to recursive_directory_iterator().

Otherwise, cease iteration of the directory currently being iterated over, and continue iteration over the parent directory.

Remarks: Any copies of the previous value of *this are no longer required to be dereferenceable nor to be in the domain of ==.

void disable_recursion_pending();

Postconditions: recursion_pending() == false.

[Note 4:

disable_recursion_pending() is used to prevent unwanted recursion into a directory.

— end note]

These functions enable use of recursive_directory_iterator with range-based for statements.

recursive_directory_iterator begin(recursive_directory_iterator iter) noexcept;

recursive_directory_iterator end(recursive_directory_iterator) noexcept;

Returns: recursive_directory_iterator().