[filesystems] - C++17 → C++20

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@@ -1,34 +1,69 @@
 ## File systems <a id="filesystems">[[filesystems]]</a>
 ### General <a id="fs.general">[[fs.general]]</a>
-This subclause describes operations on file systems and their
-components, such as paths, regular files, and directories.
 ### Conformance <a id="fs.conformance">[[fs.conformance]]</a>
 Conformance is specified in terms of behavior. Ideal behavior is not
 always implementable, so the conformance subclauses take that into
 account.
 #### POSIX conformance <a id="fs.conform.9945">[[fs.conform.9945]]</a>
-Some behavior is specified by reference to POSIX ([[fs.norm.ref]]). How
 such behavior is actually implemented is unspecified.
 [*Note 1*: This constitutes an “as if” rule allowing implementations to
 call native operating system or other APIs. — *end note*]
-Implementations are encouraged to provide such behavior as it is defined
-by POSIX. Implementations shall document any behavior that differs from
-the behavior defined by POSIX. Implementations that do not support exact
-POSIX behavior are encouraged to provide behavior as close to POSIX
-behavior as is reasonable given the limitations of actual operating
-systems and file systems. If an implementation cannot provide any
-reasonable behavior, the implementation shall report an error as
-specified in  [[fs.err.report]].
 [*Note 2*: This allows users to rely on an exception being thrown or an
 error code being set when an implementation cannot provide any
 reasonable behavior. — *end note*]
@@ -41,225 +76,88 @@ other features of more capable file systems, so implementations are not
 required to support those features on the FAT file system but instead
 are required to report an error as described above. — *end example*]
 #### Operating system dependent behavior conformance <a id="fs.conform.os">[[fs.conform.os]]</a>
-Some behavior is specified as being operating system dependent (
-[[fs.def.osdep]]). The operating system an implementation is dependent
-upon is *implementation-defined*.
 It is permissible for an implementation to be dependent upon an
 operating system emulator rather than the actual underlying operating
 system.
 #### File system race behavior <a id="fs.race.behavior">[[fs.race.behavior]]</a>
-Behavior is undefined if calls to functions provided by this subclause
-introduce a file system race ([[fs.def.race]]).
 If the possibility of a file system race would make it unreliable for a
 program to test for a precondition before calling a function described
-herein, *Requires:* is not specified for the function.
 [*Note 1*: As a design practice, preconditions are not specified when
 it is unreasonable for a program to detect them prior to calling the
 function. — *end note*]
 ### Normative references <a id="fs.norm.ref">[[fs.norm.ref]]</a>
-This subclause mentions commercially available operating systems for
-purposes of exposition.[^41]
-### Terms and definitions <a id="fs.definitions">[[fs.definitions]]</a>
-A path that unambiguously identifies the location of a file without
-reference to an additional starting location. The elements of a path
-that determine if it is absolute are operating system dependent.
-A file within a file system that acts as a container of directory
-entries that contain information about other files, possibly including
-other directory files.
-An object within a file system that holds user or system data. Files can
-be written to, or read from, or both. A file has certain attributes,
-including type. File types include regular files and directories. Other
-types of files, such as symbolic links ([[fs.def.symlink]]), may be
-supported by the implementation.
-A collection of files and their attributes.
-The condition that occurs when multiple threads, processes, or computers
-interleave access and modification of the same object within a file
-system.
-The name of a file. Filenames *dot* and *dot-dot*, consisting solely of
-one and two period characters respectively, have special meaning. The
-following characteristics of filenames are operating system dependent:
-- The permitted characters. \[*Example 1*: Some operating systems
-  prohibit the ASCII control characters (0x00 – 0x1F) in
-  filenames. — *end example*]
-- The maximum permitted length.
-- Filenames that are not permitted.
-- Filenames that have special meaning.
-- Case awareness and sensitivity during path resolution.
-- Special rules that may apply to file types other than regular files,
-  such as directories.
-A link ([[fs.def.link]]) to an existing file. Some file systems support
-multiple hard links to a file. If the last hard link to a file is
-removed, the file itself is removed.
-[*Note 1*: A hard link can be thought of as a shared-ownership smart
-pointer to a file. — *end note*]
-An object that associates a filename with a file. Several links can
-associate names with the same file.
-For narrow character strings, the operating system dependent current
-encoding for pathnames ([[fs.def.pathname]]). For wide character
-strings, the implementation-defined execution wide-character set
-encoding ([[lex.charset]]).
-The operating system dependent pathname format accepted by the host
-operating system.
-A path in normal form is said to be *normalized*. The process of
-obtaining a normalized path from a path that is not in normal form is
-called *normalization*.
-Normalization of a generic format pathname means:
-1.  If the path is empty, stop.
-2.  Replace each slash character in the *root-name* with a
-    *preferred-separator*.
-3.  Replace each *directory-separator* with a *preferred-separator*.
-    \[*Note 2*: The generic pathname grammar ([[fs.path.generic]])
-    defines *directory-separator* as one or more slashes and
-    *preferred-separator*s. — *end note*]
-4.  Remove each *dot* filename and any immediately following
-    *directory-separator*.
-5.  As long as any appear, remove a non-*dot-dot* filename immediately
-    followed by a *directory-separator* and a *dot-dot* filename, along
-    with any immediately following *directory-separator*.
-6.  If there is a *root-directory*, remove all *dot-dot* filenames and
-    any *directory-separator*s immediately following them.
-    \[*Note 3*: These *dot-dot* filenames attempt to refer to
-    nonexistent parent directories. — *end note*]
-7.  If the last filename is *dot-dot*, remove any trailing
-    *directory-separator*.
-8.  If the path is empty, add a *dot*.
-Behavior that is dependent upon the behavior and characteristics of an
-operating system. See  [[fs.conform.os]].
-the directory that both contains a directory entry for the given
-directory and is represented by the filename *dot-dot* in the given
-directory.
-a directory containing a directory entry for the file under discussion.
-A sequence of elements that identify the location of a file within a
-filesystem. The elements are the *root-name*ₒₚₜ , *root-directory*ₒₚₜ ,
-and an optional sequence of filenames. The maximum number of elements in
-the sequence is operating system dependent.
-A character string that represents the name of a path. Pathnames are
-formatted according to the generic pathname format grammar (
-[[fs.path.generic]]) or an operating system dependent native pathname
-format.
-Pathname resolution is the operating system dependent mechanism for
-resolving a pathname to a particular file in a file hierarchy. There may
-be multiple pathnames that resolve to the same file.
-[*Example 2*: POSIX specifies the mechanism in section 4.11, Pathname
-resolution. — *end example*]
-A path that is not absolute, and as such, only unambiguously identifies
-the location of a file when resolved ([[fs.def.pathres]]) relative to
-an implied starting location. The elements of a path that determine if
-it is relative are operating system dependent.
-[*Note 4*: Pathnames “.” and “..” are relative paths. — *end note*]
-A type of file with the property that when the file is encountered
-during pathname resolution, a string stored by the file is used to
-modify the pathname resolution.
-[*Note 5*: Symbolic links are often called symlinks. A symbolic link
-can be thought of as a raw pointer to a file. If the file pointed to
-does not exist, the symbolic link is said to be a “dangling” symbolic
-link. — *end note*]
 ### Requirements <a id="fs.req">[[fs.req]]</a>
-Throughout this subclause, `char`, `wchar_t`, `char16_t`, and `char32_t`
-are collectively called *encoded character types*.
 Functions with template parameters named `EcharT` shall not participate
 in overload resolution unless `EcharT` is one of the encoded character
 types.
-Template parameters named `InputIterator` shall meet the input iterator
-requirements ([[input.iterators]]) and shall have a value type that is
-one of the encoded character types.
 [*Note 1*: Use of an encoded character type implies an associated
 character set and encoding. Since `signed char` and `unsigned char` have
 no implied character set and encoding, they are not included as
 permitted types. — *end note*]
-Template parameters named `Allocator` shall meet the Allocator
-requirements ([[allocator.requirements]]).
 #### Namespaces and headers <a id="fs.req.namespace">[[fs.req.namespace]]</a>
-Unless otherwise specified, references to entities described in this
-subclause are assumed to be qualified with `::std::filesystem::`.
 ### Header `<filesystem>` synopsis <a id="fs.filesystem.syn">[[fs.filesystem.syn]]</a>
 ``` cpp
 namespace std::filesystem {
   // [fs.class.path], paths
   class path;
   // [fs.path.nonmember], path non-member functions
   void swap(path& lhs, path& rhs) noexcept;
   size_t hash_value(const path& p) noexcept;
- bool operator==(const path& lhs, const path& rhs) noexcept;
-  bool operator!=(const path& lhs, const path& rhs) noexcept;
-  bool operator< (const path& lhs, const path& rhs) noexcept;
-  bool operator<=(const path& lhs, const path& rhs) noexcept;
-  bool operator> (const path& lhs, const path& rhs) noexcept;
-  bool operator>=(const path& lhs, const path& rhs) noexcept;
-  path operator/ (const path& lhs, const path& rhs);
-  // [fs.path.io], path inserter and extractor
-  template <class charT, class traits>
-    basic_ostream<charT, traits>&
-      operator<<(basic_ostream<charT, traits>& os, const path& p);
-  template <class charT, class traits>
-    basic_istream<charT, traits>&
-      operator>>(basic_istream<charT, traits>& is, path& p);
-  // [fs.path.factory], path factory functions
-  template <class Source>
-    path u8path(const Source& source);
-  template <class InputIterator>
-    path u8path(InputIterator first, InputIterator last);
-  // [fs.class.filesystem_error], filesystem errors
   class filesystem_error;
-  // [fs.class.directory_entry], directory entries
   class directory_entry;
-  // [fs.class.directory_iterator], directory iterators
   class directory_iterator;
   // [fs.dir.itr.nonmembers], range access for directory iterators
   directory_iterator begin(directory_iterator iter) noexcept;
   directory_iterator end(const directory_iterator&) noexcept;
@@ -269,53 +167,55 @@ namespace std::filesystem {
   // [fs.rec.dir.itr.nonmembers], range access for recursive directory iterators
   recursive_directory_iterator begin(recursive_directory_iterator iter) noexcept;
   recursive_directory_iterator end(const recursive_directory_iterator&) noexcept;
-  // [fs.class.file_status], file status
   class file_status;
   struct space_info {
     uintmax_t capacity;
     uintmax_t free;
     uintmax_t available;
   };
   // [fs.enum], enumerations
   enum class file_type;
   enum class perms;
   enum class perm_options;
   enum class copy_options;
   enum class directory_options;
-  using file_time_type = chrono::time_point<trivial-clock>;
   // [fs.op.funcs], filesystem operations
-  path absolute(const path& p, const path& base = current_path());
-  path canonical(const path& p, const path& base = current_path());
   path canonical(const path& p, error_code& ec);
-  path canonical(const path& p, const path& base, error_code& ec);
   void copy(const path& from, const path& to);
-  void copy(const path& from, const path& to, error_code& ec) noexcept;
   void copy(const path& from, const path& to, copy_options options);
   void copy(const path& from, const path& to, copy_options options,
-            error_code& ec) noexcept;
   bool copy_file(const path& from, const path& to);
-  bool copy_file(const path& from, const path& to, error_code& ec) noexcept;
   bool copy_file(const path& from, const path& to, copy_options option);
   bool copy_file(const path& from, const path& to, copy_options option,
-                 error_code& ec) noexcept;
   void copy_symlink(const path& existing_symlink, const path& new_symlink);
   void copy_symlink(const path& existing_symlink, const path& new_symlink,
                     error_code& ec) noexcept;
   bool create_directories(const path& p);
-  bool create_directories(const path& p, error_code& ec) noexcept;
   bool create_directory(const path& p);
   bool create_directory(const path& p, error_code& ec) noexcept;
   bool create_directory(const path& p, const path& attributes);
@@ -337,17 +237,17 @@ namespace std::filesystem {
   path current_path();
   path current_path(error_code& ec);
   void current_path(const path& p);
   void current_path(const path& p, error_code& ec) noexcept;
   bool exists(file_status s) noexcept;
   bool exists(const path& p);
   bool exists(const path& p, error_code& ec) noexcept;
-  bool equivalent(const path& p1, const path& p2);
-  bool equivalent(const path& p1, const path& p2, error_code& ec) noexcept;
   uintmax_t file_size(const path& p);
   uintmax_t file_size(const path& p, error_code& ec) noexcept;
   uintmax_t hard_link_count(const path& p);
   uintmax_t hard_link_count(const path& p, error_code& ec) noexcept;
@@ -363,11 +263,11 @@ namespace std::filesystem {
   bool is_directory(file_status s) noexcept;
   bool is_directory(const path& p);
   bool is_directory(const path& p, error_code& ec) noexcept;
   bool is_empty(const path& p);
-  bool is_empty(const path& p, error_code& ec) noexcept;
   bool is_fifo(file_status s) noexcept;
   bool is_fifo(const path& p);
   bool is_fifo(const path& p, error_code& ec) noexcept;
@@ -410,11 +310,11 @@ namespace std::filesystem {
   bool remove(const path& p);
   bool remove(const path& p, error_code& ec) noexcept;
   uintmax_t remove_all(const path& p);
-  uintmax_t remove_all(const path& p, error_code& ec) noexcept;
   void rename(const path& from, const path& to);
   void rename(const path& from, const path& to, error_code& ec) noexcept;
   void resize_file(const path& p, uintmax_t size);
@@ -437,15 +337,13 @@ namespace std::filesystem {
   path weakly_canonical(const path& p);
   path weakly_canonical(const path& p, error_code& ec);
 }
 ```
-`trivial-clock` is an *implementation-defined* type that satisfies the
-`TrivialClock` requirements ([[time.clock.req]]) and that is capable of
-representing and measuring file time values. Implementations should
-ensure that the resolution and range of `file_time_type` reflect the
-operating system dependent resolution and range of file time values.
 ### Error reporting <a id="fs.err.report">[[fs.err.report]]</a>
 Filesystem library functions often provide two overloads, one that
 throws an exception to report file system errors, and another that sets
@@ -491,22 +389,49 @@ follows, unless otherwise specified:
   appropriate for the specific operating system dependent error.
   Otherwise, `clear()` is called on the `error_code&` argument.
 ### Class `path` <a id="fs.class.path">[[fs.class.path]]</a>
-An object of class `path` represents a path ([[fs.def.path]]) and
-contains a pathname ([[fs.def.pathname]]). Such an object is concerned
-only with the lexical and syntactic aspects of a path. The path does not
-necessarily exist in external storage, and the pathname is not
-necessarily valid for the current operating system or for a particular
-file system.
 [*Note 1*: Class `path` is used to support the differences between the
 string types used by different operating systems to represent pathnames,
 and to perform conversions between encodings when
 necessary. — *end note*]
 ``` cpp
 namespace std::filesystem {
   class path {
   public:
     using value_type  = see below;
@@ -537,11 +462,11 @@ namespace std::filesystem {
     path& operator=(string_type&& source);
     path& assign(string_type&& source);
     template<class Source>
       path& operator=(const Source& source);
     template<class Source>
-      path& assign(const Source& source)
     template<class InputIterator>
       path& assign(InputIterator first, InputIterator last);
     // [fs.path.append], appends
     path& operator/=(const path& p);
@@ -573,10 +498,16 @@ namespace std::filesystem {
     path& remove_filename();
     path& replace_filename(const path& replacement);
     path& replace_extension(const path& replacement = path());
     void  swap(path& rhs) noexcept;
     // [fs.path.native.obs], native format observers
     const string_type& native() const noexcept;
     const value_type*  c_str() const noexcept;
     operator string_type() const;
@@ -584,22 +515,22 @@ namespace std::filesystem {
              class Allocator = allocator<EcharT>>
       basic_string<EcharT, traits, Allocator>
         string(const Allocator& a = Allocator()) const;
     std::string    string() const;
     std::wstring   wstring() const;
-    std::string    u8string() const;
     std::u16string u16string() const;
     std::u32string u32string() const;
     // [fs.path.generic.obs], generic format observers
     template<class EcharT, class traits = char_traits<EcharT>,
              class Allocator = allocator<EcharT>>
       basic_string<EcharT, traits, Allocator>
         generic_string(const Allocator& a = Allocator()) const;
     std::string    generic_string() const;
     std::wstring   generic_wstring() const;
-    std::string    generic_u8string() const;
     std::u16string generic_u16string() const;
     std::u32string generic_u32string() const;
     // [fs.path.compare], compare
     int compare(const path& p) const noexcept;
@@ -616,11 +547,11 @@ namespace std::filesystem {
     path filename() const;
     path stem() const;
     path extension() const;
     // [fs.path.query], query
-    bool empty() const noexcept;
     bool has_root_name() const;
     bool has_root_directory() const;
     bool has_root_path() const;
     bool has_relative_path() const;
     bool has_parent_path() const;
@@ -639,21 +570,29 @@ namespace std::filesystem {
     class iterator;
     using const_iterator = iterator;
     iterator begin() const;
     iterator end() const;
   };
 }
 ```
 `value_type` is a `typedef` for the operating system dependent encoded
 character type used to represent pathnames.
 The value of the `preferred_separator` member is the operating system
-dependent *preferred-separator* character ([[fs.path.generic]]).
-[*Example 1*: For POSIX-based operating systems, `value_type` is `char`
 and `preferred_separator` is the slash character (`'/'`). For
 Windows-based operating systems, `value_type` is `wchar_t` and
 `preferred_separator` is the backslash character
 (`L'\\'`). — *end example*]
@@ -701,31 +640,42 @@ preferred-separator:
 ``` bnf
 fallback-separator:
     /, if *preferred-separator* is not /
 ```
-[*Note 1*: Operating systems often place restrictions on the characters
-that may be used in a *filename*. For wide portability, users may wish
-to limit *filename* characters to the POSIX Portable Filename Character
-Set:
   `A B C D E F G H I J K L M N O P Q R S T U V W X Y Z`
   `a b c d e f g h i j k l m n o p q r s t u v w x y z`
   `0 1 2 3 4 5 6 7 8 9 . _ -` — *end note*]
 Except in a *root-name*, multiple successive *directory-separator*
 characters are considered to be the same as one *directory-separator*
 character.
-The filename *dot* ([[fs.def.filename]]) is treated as a reference to
-the current directory. The filename *dot-dot* ([[fs.def.filename]]) is
-treated as a reference to the parent directory. What the filename
-*dot-dot* refers to relative to *root-directory* is
 *implementation-defined*. Specific filenames may have special meanings
 for a particular operating system.
-A *root-name* identifies the starting location for pathname resolution (
-[[fs.def.pathres]]). If there are no operating system dependent
 *root-name*s, at least one *implementation-defined* *root-name* is
 required.
 [*Note 2*: Many operating systems define a name beginning with two
 *directory-separator* characters as a *root-name* that identifies
@@ -738,17 +688,42 @@ longest sequence of characters is chosen.
 [*Note 3*: On a POSIX-like operating system, it is impossible to have a
 *root-name* and a *relative-path* without an intervening
 *root-directory* element. — *end note*]
-#### `path` conversions <a id="fs.path.cvt">[[fs.path.cvt]]</a>
-##### `path` argument format conversions <a id="fs.path.fmt.cvt">[[fs.path.fmt.cvt]]</a>
 [*Note 1*:
-The format conversions described in this section are not applied on
 POSIX-based operating systems because on these systems:
 - The generic format is acceptable as a native path.
 - There is no need to distinguish between native format and generic
   format in function arguments.
@@ -757,15 +732,15 @@ POSIX-based operating systems because on these systems:
 — *end note*]
 Several functions are defined to accept *detected-format* arguments,
 which are character sequences. A detected-format argument represents a
-path using either a pathname in the generic format (
-[[fs.path.generic]]) or a pathname in the native format (
-[[fs.def.native]]). Such an argument is taken to be in the generic
-format if and only if it matches the generic format and is not
-acceptable to the operating system as a native path.
 [*Note 2*: Some operating systems may have no unambiguous way to
 distinguish between native format and generic format arguments. This is
 by design as it simplifies use for operating systems that do not require
 disambiguation. An implementation for an operating system where
@@ -784,12 +759,12 @@ native-to-generic and generic-to-native formats respectively. If
 If the native format requires paths for regular files to be formatted
 differently from paths for directories, the path shall be treated as a
 directory path if its last element is a *directory-separator*, otherwise
 it shall be treated as a path to a regular file.
-[*Note 4*: A path stores a native format pathname (
-[[fs.path.native.obs]]) and acts as if it also stores a generic format
 pathname, related as given below. The implementation may generate the
 generic format pathname based on the native format pathname (and
 possibly other information) when requested. — *end note*]
 When a path is constructed from or is assigned a single representation
@@ -802,95 +777,101 @@ the other representation. The value *q* converts to *p* (by *G* or *N*
 as appropriate) if any such value does so; *q* is otherwise unspecified.
 [*Note 5*: If *q* is the result of converting any path at all, it is
 the result of converting *p*. — *end note*]
-##### `path` type and encoding conversions <a id="fs.path.type.cvt">[[fs.path.type.cvt]]</a>
 For member function arguments that take character sequences representing
 paths and for member functions returning strings, value type and
 encoding conversion is performed if the value type of the argument or
 return value differs from `path::value_type`. For the argument or return
 value, the method of conversion and the encoding to be converted to is
 determined by its value type:
-- `char`: The encoding is the native narrow encoding (
- [[fs.def.native.encode]]). The method of conversion, if any, is
-  operating system dependent. \[*Note 6*: For POSIX-based operating
- systems `path::value_type` is `char` so no conversion from `char`
- value type arguments or to `char` value type return values is
- performed. For Windows-based operating systems, the native narrow
-  encoding is determined by calling a Windows API
   function. — *end note*] \[*Note 7*: This results in behavior
   identical to other C and C++ standard library functions that perform
-  file operations using narrow character strings to identify paths.
   Changing this behavior would be surprising and error
   prone. — *end note*]
-- `wchar_t`: The encoding is the native wide encoding (
- [[fs.def.native.encode]]). The method of conversion is unspecified.
- \[*Note 8*: For Windows-based operating systems `path::value_type` is
-  `wchar_t` so no conversion from `wchar_t` value type arguments or to
- `wchar_t` value type return values is performed. — *end note*]
 - `char16_t`: The encoding is UTF-16. The method of conversion is
   unspecified.
 - `char32_t`: The encoding is UTF-32. The method of conversion is
   unspecified.
 If the encoding being converted to has no representation for source
 characters, the resulting converted characters, if any, are unspecified.
 Implementations should not modify member function arguments if already
 of type `path::value_type`.
-#### `path` requirements <a id="fs.path.req">[[fs.path.req]]</a>
-In addition to the requirements ([[fs.req]]), function template
-parameters named `Source` shall be one of:
 - `basic_string<EcharT, traits, Allocator>`. A function argument
   `const Source&` `source` shall have an effective range
   \[`source.begin()`, `source.end()`).
 - `basic_string_view<EcharT, traits>`. A function argument
   `const Source&` `source` shall have an effective range
   \[`source.begin()`, `source.end()`).
-- A type meeting the input iterator requirements that iterates over a
-  NTCTS. The value type shall be an encoded character type. A function
-  argument `const Source&` `source` shall have an effective range
-  \[`source`, `end`) where `end` is the first iterator value with an
-  element value equal to `iterator_traits<Source>::value_type()`.
 - A character array that after array-to-pointer decay results in a
   pointer to the start of a NTCTS. The value type shall be an encoded
   character type. A function argument `const Source&` `source` shall
   have an effective range \[`source`, `end`) where `end` is the first
   iterator value with an element value equal to
   `iterator_traits<decay_t<Source>>::value_type()`.
 Functions taking template parameters named `Source` shall not
-participate in overload resolution unless either
 - `Source` is a specialization of `basic_string` or `basic_string_view`,
   or
 - the *qualified-id* `iterator_traits<decay_t<Source>>::value_type` is
-  valid and denotes a possibly `const` encoded character type (
-  [[temp.deduct]]).
-[*Note 1*: See path conversions ([[fs.path.cvt]]) for how the value
-types above and their encodings convert to `path::value_type` and its
 encoding. — *end note*]
 Arguments of type `Source` shall not be null pointers.
-#### `path` members <a id="fs.path.member">[[fs.path.member]]</a>
-##### `path` constructors <a id="fs.path.construct">[[fs.path.construct]]</a>
 ``` cpp
 path() noexcept;
 ```
-*Effects:* Constructs an object of class `path`.
-*Postconditions:* `empty() == true`.
 ``` cpp
 path(const path& p);
 path(path&& p) noexcept;
 ```
@@ -903,49 +884,48 @@ state.
 ``` cpp
 path(string_type&& source, format fmt = auto_format);
 ```
 *Effects:* Constructs an object of class `path` for which the pathname
-in the detected-format of `source` has the original value of
-`source` ([[fs.path.fmt.cvt]]), converting format if
-required ([[fs.path.fmt.cvt]]). `source` is left in a valid but
-unspecified state.
 ``` cpp
 template<class Source>
   path(const Source& source, format fmt = auto_format);
 template<class InputIterator>
   path(InputIterator first, InputIterator last, format fmt = auto_format);
 ```
-*Effects:* Let `s` be the effective range of `source` ([[fs.path.req]])
-or the range \[`first`, `last`), with the encoding converted if
-required ([[fs.path.cvt]]). Finds the detected-format of
-`s` ([[fs.path.fmt.cvt]]) and constructs an object of class `path` for
-which the pathname in that format is `s`.
 ``` cpp
 template<class Source>
   path(const Source& source, const locale& loc, format fmt = auto_format);
 template<class InputIterator>
   path(InputIterator first, InputIterator last, const locale& loc, format fmt = auto_format);
 ```
-*Requires:* The value type of `Source` and `InputIterator` is `char`.
 *Effects:* Let `s` be the effective range of `source` or the range
 \[`first`, `last`), after converting the encoding as follows:
 - If `value_type` is `wchar_t`, converts to the native wide
-  encoding ([[fs.def.native.encode]]) using the
   `codecvt<wchar_t, char, mbstate_t>` facet of `loc`.
 - Otherwise a conversion is performed using the
   `codecvt<wchar_t, char, mbstate_t>` facet of `loc`, and then a second
-  conversion to the current narrow encoding.
-Finds the detected-format of `s` ([[fs.path.fmt.cvt]]) and constructs
-an object of class `path` for which the pathname in that format is `s`.
 [*Example 1*:
 A string is to be read from a database that is encoded in ISO/IEC
 8859-1, and used to create a directory:
@@ -959,27 +939,27 @@ fs::create_directory(fs::path(latin1_string, latin1_locale));
 ```
 For POSIX-based operating systems, the path is constructed by first
 using `latin1_facet` to convert ISO/IEC 8859-1 encoded `latin1_string`
 to a wide character string in the native wide
-encoding ([[fs.def.native.encode]]). The resulting wide string is then
-converted to a narrow character pathname string in the current native
-narrow encoding. If the native wide encoding is UTF-16 or UTF-32, and
-the current native narrow encoding is UTF-8, all of the characters in
 the ISO/IEC 8859-1 character set will be converted to their Unicode
-representation, but for other native narrow encodings some characters
 may have no representation.
 For Windows-based operating systems, the path is constructed by using
 `latin1_facet` to convert ISO/IEC 8859-1 encoded `latin1_string` to a
 UTF-16 encoded wide character pathname string. All of the characters in
 the ISO/IEC 8859-1 character set will be converted to their Unicode
 representation.
 — *end example*]
-##### `path` assignments <a id="fs.path.assign">[[fs.path.assign]]</a>
 ``` cpp
 path& operator=(const path& p);
 ```
@@ -1019,18 +999,18 @@ template <class Source>
   path& assign(const Source& source);
 template<class InputIterator>
   path& assign(InputIterator first, InputIterator last);
 ```
-*Effects:* Let `s` be the effective range of `source` ([[fs.path.req]])
-or the range \[`first`, `last`), with the encoding converted if
-required ([[fs.path.cvt]]). Finds the detected-format of
-`s` ([[fs.path.fmt.cvt]]) and sets the pathname in that format to `s`.
 *Returns:* `*this`.
-##### `path` appends <a id="fs.path.append">[[fs.path.append]]</a>
 The append operations use `operator/=` to denote their semantic effect
 of appending *preferred-separator* when needed.
 ``` cpp
@@ -1053,26 +1033,28 @@ Otherwise, modifies `*this` as if by these steps:
   pathname.
 [*Example 2*:
 Even if `//host` is interpreted as a *root-name*, both of the paths
-`path("//host")/"foo"` and `path("//host/")/"foo"` equal `"//host/foo"`.
 Expression examples:
 ``` cpp
 // On POSIX,
-path("foo") / ""; // yields "foo/"
-path("foo") / "/bar"; // yields "/bar"
-// On Windows, backslashes replace slashes in the above yields
 // On Windows,
-path("foo") / "c:/bar"; // yields "c:/bar"
-path("foo") / "c:"; // yields "c:"
-path("c:") / ""; // yields "c:"
-path("c:foo") / "/bar"; // yields "c:/bar"
-path("c:foo") / "c:bar"; // yields "c:foo/bar"
 ```
 — *end example*]
 *Returns:* `*this`.
@@ -1091,22 +1073,19 @@ template <class InputIterator>
   path& append(InputIterator first, InputIterator last);
 ```
 *Effects:* Equivalent to: `return operator/=(path(first, last));`
-##### `path` concatenation <a id="fs.path.concat">[[fs.path.concat]]</a>
 ``` cpp
 path& operator+=(const path& x);
 path& operator+=(const string_type& x);
 path& operator+=(basic_string_view<value_type> x);
 path& operator+=(const value_type* x);
-path& operator+=(value_type x);
 template<class Source>
   path& operator+=(const Source& x);
-template <class EcharT>
-  path& operator+=(EcharT x);
 template<class Source>
   path& concat(const Source& x);
 ```
 *Effects:* Appends `path(x).native()` to the pathname in the native
@@ -1115,24 +1094,32 @@ format.
 [*Note 2*: This directly manipulates the value of `native()` and may
 not be portable between operating systems. — *end note*]
 *Returns:* `*this`.
 ``` cpp
 template<class InputIterator>
   path& concat(InputIterator first, InputIterator last);
 ```
-*Effects:* Equivalent to `return *this += path(first, last)`.
-##### `path` modifiers <a id="fs.path.modifiers">[[fs.path.modifiers]]</a>
 ``` cpp
 void clear() noexcept;
 ```
-*Postconditions:* `empty() == true`.
 ``` cpp
 path& make_preferred();
 ```
@@ -1170,15 +1157,15 @@ output is:
 ``` cpp
 path& remove_filename();
 ```
-*Postconditions:* `!has_filename()`.
 *Effects:* Remove the generic format pathname of `filename()` from the
 generic format pathname.
 *Returns:* `*this`.
 [*Example 4*:
 ``` cpp
@@ -1216,12 +1203,12 @@ path("/").replace_filename("bar");     // yields "/bar" on POSIX
 path& replace_extension(const path& replacement = path());
 ```
 *Effects:*
-- Any existing `extension()(` [[fs.path.decompose]]`)` is removed from
- the pathname in the generic format, then
 - If `replacement` is not empty and does not begin with a dot character,
   a dot character is appended to the pathname in the generic format,
   then
 - `operator+=(replacement);`.
@@ -1233,14 +1220,14 @@ void swap(path& rhs) noexcept;
 *Effects:* Swaps the contents (in all formats) of the two paths.
 *Complexity:* Constant time.
-##### `path` native format observers <a id="fs.path.native.obs">[[fs.path.native.obs]]</a>
 The string returned by all native format observers is in the native
-pathname format ([[fs.def.native]]).
 ``` cpp
 const string_type& native() const noexcept;
 ```
@@ -1248,11 +1235,11 @@ const string_type& native() const noexcept;
 ``` cpp
 const value_type* c_str() const noexcept;
 ```
-*Returns:* Equivalent to `native().c_str()`.
 ``` cpp
 operator string_type() const;
 ```
@@ -1276,26 +1263,25 @@ be performed by `a`. Conversion, if any, is specified by
 [[fs.path.cvt]].
 ``` cpp
 std::string string() const;
 std::wstring wstring() const;
-std::string u8string() const;
 std::u16string u16string() const;
 std::u32string u32string() const;
 ```
-*Returns:* `pathstring`.
 *Remarks:* Conversion, if any, is performed as specified by
-[[fs.path.cvt]]. The encoding of the string returned by `u8string()` is
-always UTF-8.
-##### `path` generic format observers <a id="fs.path.generic.obs">[[fs.path.generic.obs]]</a>
 Generic format observer functions return strings formatted according to
-the generic pathname format ([[fs.path.generic]]). A single slash
-(`'/'`) character is used as the *directory-separator*.
 [*Example 1*:
 On an operating system that uses backslash as its *preferred-separator*,
@@ -1321,53 +1307,51 @@ be performed by `a`. Conversion, if any, is specified by
 [[fs.path.cvt]].
 ``` cpp
 std::string generic_string() const;
 std::wstring generic_wstring() const;
-std::string generic_u8string() const;
 std::u16string generic_u16string() const;
 std::u32string generic_u32string() const;
 ```
 *Returns:* The pathname in the generic format.
-*Remarks:* Conversion, if any, is specified by  [[fs.path.cvt]]. The
-encoding of the string returned by `generic_u8string()` is always UTF-8.
-##### `path` compare <a id="fs.path.compare">[[fs.path.compare]]</a>
 ``` cpp
 int compare(const path& p) const noexcept;
 ```
 *Returns:*
-- A value less than `0`, if `native()` for the elements of `*this` are
- lexicographically less than `native()` for the elements of `p`;
- otherwise,
-- a value greater than `0`, if `native()` for the elements of `*this`
- are lexicographically greater than `native()` for the elements of `p`;
-  otherwise,
-- `0`.
-*Remarks:* The elements are determined as if by iteration over the
-half-open range \[`begin()`, `end()`) for `*this` and `p`.
 ``` cpp
-int compare(const string_type& s) const
 int compare(basic_string_view<value_type> s) const;
 ```
-*Returns:* `compare(path(s))`.
-``` cpp
-int compare(const value_type* s) const
-```
-*Returns:* `compare(path(s))`.
-##### `path` decomposition <a id="fs.path.decompose">[[fs.path.decompose]]</a>
 ``` cpp
 path root_name() const;
 ```
@@ -1390,20 +1374,21 @@ path root_path() const;
 ``` cpp
 path relative_path() const;
 ```
 *Returns:* A `path` composed from the pathname in the generic format, if
-`!empty()`, beginning with the first *filename* after *root-path*.
-Otherwise, `path()`.
 ``` cpp
 path parent_path() const;
 ```
-*Returns:* `*this` if `!has_relative_path()`, otherwise a path whose
-generic format pathname is the longest prefix of the generic format
-pathname of `*this` that produces one fewer element in its iteration.
 ``` cpp
 path filename() const;
 ```
@@ -1450,11 +1435,11 @@ for (; !p.extension().empty(); p = p.stem())
 ``` cpp
 path extension() const;
 ```
-*Returns:* a path whose pathname in the generic format is the suffix of
 `filename()` not included in `stem()`.
 [*Example 8*:
 ``` cpp
@@ -1473,18 +1458,18 @@ extension. — *end note*]
 [*Note 5*: On non-POSIX operating systems, for a path `p`, it may not
 be the case that `p.stem() + p.extension() == p.filename()`, even though
 the generic format pathnames are the same. — *end note*]
-##### `path` query <a id="fs.path.query">[[fs.path.query]]</a>
 ``` cpp
-bool empty() const noexcept;
 ```
-*Returns:* `true` if the pathname in the generic format is empty, else
-`false`.
 ``` cpp
 bool has_root_path() const;
 ```
@@ -1535,11 +1520,11 @@ bool has_extension() const;
 ``` cpp
 bool is_absolute() const;
 ```
 *Returns:* `true` if the pathname in the native format contains an
-absolute path ([[fs.def.absolute.path]]), else `false`.
 [*Example 9*: `path("/").is_absolute()` is `true` for POSIX-based
 operating systems, and `false` for Windows-based operating
 systems. — *end example*]
@@ -1547,18 +1532,18 @@ systems. — *end example*]
 bool is_relative() const;
 ```
 *Returns:* `!is_absolute()`.
-##### `path` generation <a id="fs.path.gen">[[fs.path.gen]]</a>
 ``` cpp
 path lexically_normal() const;
 ```
 *Returns:* A path whose pathname in the generic format is the normal
-form ([[fs.def.normal.form]]) of the pathname in the generic format of
 `*this`.
 [*Example 10*:
 ``` cpp
@@ -1575,29 +1560,40 @@ slashes, but that does not affect `path` equality.
 ``` cpp
 path lexically_relative(const path& base) const;
 ```
 *Returns:* `*this` made relative to `base`. Does not
-resolve ([[fs.def.pathres]]) symlinks. Does not first
-normalize ([[fs.def.normal.form]]) `*this` or `base`.
-*Effects:* If `root_name() != base.root_name()` is `true` or
-`is_absolute() != base.is_absolute()` is `true` or
-`!has_root_directory() && base.has_root_directory()` is `true`, returns
-`path()`. Determines the first mismatched element of `*this` and `base`
-as if by:
 ``` cpp
 auto [a, b] = mismatch(begin(), end(), base.begin(), base.end());
 ```
 Then,
 - if `a == end()` and `b == base.end()`, returns `path(".")`; otherwise
 - let `n` be the number of *filename* elements in \[`b`, `base.end()`)
-  that are not *dot* or *dot-dot* minus the number that are *dot-dot*.
-  If `n<0,` returns `path()`; otherwise
 - returns an object of class `path` that is default-constructed,
   followed by
   - application of `operator/=(path(".."))` `n` times, and then
   - application of `operator/=` for each element in \[`a`, `end()`).
@@ -1616,41 +1612,41 @@ The above assertions will succeed. On Windows, the returned path’s
 *directory-separator* characters will be backslashes rather than
 slashes, but that does not affect `path` equality.
 — *end example*]
-[*Note 6*: If symlink following semantics are desired, use the
 operational function `relative()`. — *end note*]
-[*Note 7*: If normalization ([[fs.def.normal.form]]) is needed to
-ensure consistent matching of elements, apply `lexically_normal()` to
-`*this`, `base`, or both. — *end note*]
 ``` cpp
 path lexically_proximate(const path& base) const;
 ```
 *Returns:* If the value of `lexically_relative(base)` is not an empty
 path, return it. Otherwise return `*this`.
-[*Note 8*: If symlink following semantics are desired, use the
 operational function `proximate()`. — *end note*]
-[*Note 9*: If normalization ([[fs.def.normal.form]]) is needed to
-ensure consistent matching of elements, apply `lexically_normal()` to
-`*this`, `base`, or both. — *end note*]
-#### `path` iterators <a id="fs.path.itr">[[fs.path.itr]]</a>
 Path iterators iterate over the elements of the pathname in the generic
-format ([[fs.path.generic]]).
-A `path::iterator` is a constant iterator satisfying all the
-requirements of a bidirectional iterator ([[bidirectional.iterators]])
-except that, for dereferenceable iterators `a` and `b` of type
-`path::iterator` with `a == b`, there is no requirement that `*a` and
-`*b` are bound to the same object. Its `value_type` is `path`.
 Calling any non-const member function of a `path` object invalidates all
 iterators referring to elements of that object.
 For the elements of the pathname in the generic format, the forward
@@ -1677,171 +1673,94 @@ list above. If no elements are present, the end iterator.
 iterator end() const;
 ```
 *Returns:* The end iterator.
-#### `path` non-member functions <a id="fs.path.nonmember">[[fs.path.nonmember]]</a>
 ``` cpp
 void swap(path& lhs, path& rhs) noexcept;
 ```
-*Effects:* Equivalent to: `lhs.swap(rhs);`
 ``` cpp
 size_t hash_value (const path& p) noexcept;
 ```
 *Returns:* A hash value for the path `p`. If for two paths, `p1 == p2`
 then `hash_value(p1) == hash_value(p2)`.
 ``` cpp
-bool operator< (const path& lhs, const path& rhs) noexcept;
 ```
-*Returns:* `lhs.compare(rhs) < 0`.
-``` cpp
-bool operator<=(const path& lhs, const path& rhs) noexcept;
-```
-*Returns:* `!(rhs < lhs)`.
-``` cpp
-bool operator> (const path& lhs, const path& rhs) noexcept;
-```
-*Returns:* `rhs < lhs`.
-``` cpp
-bool operator>=(const path& lhs, const path& rhs) noexcept;
-```
-*Returns:* `!(lhs < rhs)`.
-``` cpp
-bool operator==(const path& lhs, const path& rhs) noexcept;
-```
-*Returns:* `!(lhs < rhs) && !(rhs < lhs)`.
 [*Note 1*:
 Path equality and path equivalence have different semantics.
 - Equality is determined by the `path` non-member `operator==`, which
-  considers the two path’s lexical representations only.
   \[*Example 1*: `path("foo") == "bar"` is never
   `true`. — *end example*]
 - Equivalence is determined by the `equivalent()` non-member function,
-  which determines if two paths resolve ([[fs.def.pathres]]) to the
- same file system entity. \[*Example 2*: `equivalent("foo", "bar")`
- will be `true` when both paths resolve to the same
-  file. — *end example*]
 Programmers wishing to determine if two paths are “the same” must decide
 if “the same” means “the same representation” or “resolve to the same
 actual file”, and choose the appropriate function accordingly.
 — *end note*]
 ``` cpp
-bool operator!=(const path& lhs, const path& rhs) noexcept;
 ```
-*Returns:* `!(lhs == rhs)`.
 ``` cpp
-path operator/ (const path& lhs, const path& rhs);
 ```
 *Effects:* Equivalent to: `return path(lhs) /= rhs;`
-##### `path` inserter and extractor <a id="fs.path.io">[[fs.path.io]]</a>
-``` cpp
-template <class charT, class traits>
-  basic_ostream<charT, traits>&
-    operator<<(basic_ostream<charT, traits>& os, const path& p);
-```
-*Effects:* Equivalent to: `os << quoted(p.string<charT, traits>());`
-[*Note 2*: The `quoted` function is described
-in  [[quoted.manip]]. — *end note*]
-*Returns:* `os`.
-``` cpp
-template <class charT, class traits>
-  basic_istream<charT, traits>&
-    operator>>(basic_istream<charT, traits>& is, path& p);
-```
-*Effects:* Equivalent to:
-``` cpp
-basic_string<charT, traits> tmp;
-is >> quoted(tmp);
-p = tmp;
-```
-*Returns:* `is`.
-##### `path` factory functions <a id="fs.path.factory">[[fs.path.factory]]</a>
-``` cpp
-template <class Source>
-  path u8path(const Source& source);
-template <class InputIterator>
-  path u8path(InputIterator first, InputIterator last);
-```
-*Requires:* The `source` and \[`first`, `last`) sequences are UTF-8
-encoded. The value type of `Source` and `InputIterator` is `char`.
-*Returns:*
-- If `value_type` is `char` and the current native narrow
-  encoding ([[fs.def.native.encode]]) is UTF-8, return `path(source)`
-  or `path(first, last)`; otherwise,
-- if `value_type` is `wchar_t` and the native wide encoding is UTF-16,
-  or if `value_type` is `char16_t` or `char32_t`, convert `source` or
-  \[`first`, `last`) to a temporary, `tmp`, of type `string_type` and
-  return `path(tmp)`; otherwise,
-- convert `source` or \[`first`, `last`) to a temporary, `tmp`, of type
-  `u32string` and return `path(tmp)`.
-*Remarks:* Argument format conversion ([[fs.path.fmt.cvt]]) applies to
-the arguments for these functions. How Unicode encoding conversions are
-performed is unspecified.
-[*Example 1*:
-A string is to be read from a database that is encoded in UTF-8, and
-used to create a directory using the native encoding for filenames:
-``` cpp
-namespace fs = std::filesystem;
-std::string utf8_string = read_utf8_data();
-fs::create_directory(fs::u8path(utf8_string));
-```
-For POSIX-based operating systems with the native narrow encoding set to
-UTF-8, no encoding or type conversion occurs.
-For POSIX-based operating systems with the native narrow encoding not
-set to UTF-8, a conversion to UTF-32 occurs, followed by a conversion to
-the current native narrow encoding. Some Unicode characters may have no
-native character set representation.
-For Windows-based operating systems a conversion from UTF-8 to UTF-16
-occurs.
-— *end example*]
-### Class `filesystem_error` <a id="fs.class.filesystem_error">[[fs.class.filesystem_error]]</a>
 ``` cpp
 namespace std::filesystem {
   class filesystem_error : public system_error {
   public:
@@ -1857,65 +1776,50 @@ namespace std::filesystem {
   };
 }
 ```
 The class `filesystem_error` defines the type of objects thrown as
-exceptions to report file system errors from functions described in this
-subclause.
-#### `filesystem_error` members <a id="filesystem_error.members">[[filesystem_error.members]]</a>
 Constructors are provided that store zero, one, or two paths associated
 with an error.
 ``` cpp
 filesystem_error(const string& what_arg, error_code ec);
 ```
-*Postconditions:* The postconditions of this function are indicated in
-Table  [[tab:filesystem_error.1]].
-**Table: `filesystem_error(const string&, error_code)` effects** <a id="tab:filesystem_error.1">[tab:filesystem_error.1]</a>
-| Expression              | Value              |
-| ----------------------- | ------------------ |
-| `runtime_error::what()` | `what_arg.c_str()` |
-| `code()`                | `ec`               |
-| `path1().empty()`       | `true`             |
-| `path2().empty()`       | `true`             |
 ``` cpp
 filesystem_error(const string& what_arg, const path& p1, error_code ec);
 ```
-*Postconditions:* The postconditions of this function are indicated in
-Table  [[tab:filesystem_error.2]].
-**Table: `filesystem_error(const string&, const path&, error_code)` effects** <a id="tab:filesystem_error.2">[tab:filesystem_error.2]</a>
-| Expression              | Value                            |
-| ----------------------- | -------------------------------- |
-| `runtime_error::what()` | `what_arg.c_str()`               |
-| `code()`                | `ec`                             |
-| `path1()`               | Reference to stored copy of `p1` |
-| `path2().empty()`       | `true`                           |
 ``` cpp
 filesystem_error(const string& what_arg, const path& p1, const path& p2, error_code ec);
 ```
-*Postconditions:* The postconditions of this function are indicated in
-Table  [[tab:filesystem_error.3]].
-**Table: `filesystem_error(const string&, const path&, const path&, error_code)` effects** <a id="tab:filesystem_error.3">[tab:filesystem_error.3]</a>
-| Expression              | Value                            |
-| ----------------------- | -------------------------------- |
-| `runtime_error::what()` | `what_arg.c_str()`               |
-| `code()`                | `ec`                             |
-| `path1()`               | Reference to stored copy of `p1` |
-| `path2()`               | Reference to stored copy of `p2` |
 ``` cpp
 const path& path1() const noexcept;
 ```
@@ -1931,45 +1835,46 @@ or, if none, an empty path.
 ``` cpp
 const char* what() const noexcept override;
 ```
-*Returns:* A string containing `runtime_error::what()`. The exact format
-is unspecified. Implementations are encouraged but not required to
-include `path1.native_string()` if not empty, `path2.native_string()` if
-not empty, and `system_error::what()` strings in the returned string.
 ### Enumerations <a id="fs.enum">[[fs.enum]]</a>
 #### Enum `path::format` <a id="fs.enum.path.format">[[fs.enum.path.format]]</a>
 This enum specifies constants used to identify the format of the
-character sequence, with the meanings listed in Table
-[[tab:enum.path.format]].
 [*Note 1*: For POSIX-based systems, native and generic formats are
 equivalent and the character sequence should always be interpreted in
 the same way. — *end note*]
-#### Enum class `file_type` <a id="fs.enum.file_type">[[fs.enum.file_type]]</a>
 This enum class specifies constants used to identify file types, with
-the meanings listed in Table  [[tab:fs.enum.file_type]].
 [*Note 1*: The file not being found is not considered an error while
 determining the type of a file. — *end note*]
 #### Enum class `copy_options` <a id="fs.enum.copy.opts">[[fs.enum.copy.opts]]</a>
-The `enum class` type `copy_options` is a bitmask type (
-[[bitmask.types]]) that specifies bitmask constants used to control the
-semantics of copy operations. The constants are specified in option
-groups with the meanings listed in Table  [[tab:fs.enum.copy_options]].
-Constant `none` is shown in each option group for purposes of
 exposition; implementations shall provide only a single definition.
-**Table: Enum class `copy_options`** <a id="tab:fs.enum.copy_options">[tab:fs.enum.copy_options]</a>
 | Constant             | Meaning                                                                                                                                               |
 | -------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- |
 | `none`               | (Default) Error; file already exists.                                                                                                                 |
 | `skip_existing`      | Do not overwrite existing file, do not report an error.                                                                                               |
@@ -1983,15 +1888,15 @@ exposition; implementations shall provide only a single definition.
 | `create_hard_links`  | Make hard links instead of copies of files.                                                                                                           |
 #### Enum class `perms` <a id="fs.enum.perms">[[fs.enum.perms]]</a>
-The `enum class` type `perms` is a bitmask type ([[bitmask.types]])
-that specifies bitmask constants used to identify file permissions, with
-the meanings listed in Table  [[tab:fs.enum.perms]].
-**Table: Enum class `perms`** <a id="tab:fs.enum.perms">[tab:fs.enum.perms]</a>
 | Name           | Value (octal) | POSIX macro | Definition or notes                                                                                              |
 | -------------- | ------------- | ----------- | ---------------------------------------------------------------------------------------------------------------- |
 | `none`         | `0`           |             | There are no permissions set for the file.                                                                       |
 | `owner_read`   | `0400`        | `S_IRUSR`   | Read permission, owner                                                                                           |
@@ -2014,81 +1919,85 @@ the meanings listed in Table  [[tab:fs.enum.perms]].
 | `unknown`      | `0xFFFF`      |             | The permissions are not known, such as when a `file_status` object is created without specifying the permissions |
 #### Enum class `perm_options` <a id="fs.enum.perm.opts">[[fs.enum.perm.opts]]</a>
-The `enum class` type `perm_options` is a bitmask type (
-[[bitmask.types]]) that specifies bitmask constants used to control the
-semantics of permissions operations, with the meanings listed in Table
-[[tab:enum.perm_options]]. The bitmask constants are bitmask elements.
-In Table  [[tab:enum.perm_options]] `perm` denotes a value of type
-`perms` passed to `permissions`.
-**Table: Enum class `perm_options`** <a id="tab:enum.perm_options">[tab:enum.perm_options]</a>
 | Name       | Meaning                                                                                                                                                 |
-| ---------- | ----------------------------------------------------------------------------------------------------------------------------------------------- |
 | `replace`  | `permissions` shall replace the file's permission bits with `perm`                                                                                      |
-| `add`      | `permissions` shall replace the file's permission bits with the bitwise OR of `perm` and the file's current permission bits.                    |
-| `remove`   | `permissions` shall replace the file's permission bits with the bitwise AND of the complement of `perm` and the file's current permission bits. |
 | `nofollow` | `permissions` shall change the permissions of a symbolic link itself rather than the permissions of the file the link resolves to.                      |
 #### Enum class `directory_options` <a id="fs.enum.dir.opts">[[fs.enum.dir.opts]]</a>
-The `enum class` type `directory_options` is a bitmask type (
-[[bitmask.types]]) that specifies bitmask constants used to identify
-directory traversal options, with the meanings listed in Table
-[[tab:fs.enum.directory_options]].
-**Table: Enum class `directory_options`** <a id="tab:fs.enum.directory_options">[tab:fs.enum.directory_options]</a>
 | Name                       | Meaning                                                            |
 | -------------------------- | ------------------------------------------------------------------ |
 | `none`                     | (Default) Skip directory symlinks, permission denied is an error.  |
 | `follow_directory_symlink` | Follow rather than skip directory symlinks.                        |
 | `skip_permission_denied`   | Skip directories that would otherwise result in permission denied. |
-### Class `file_status` <a id="fs.class.file_status">[[fs.class.file_status]]</a>
 ``` cpp
 namespace std::filesystem {
   class file_status {
   public:
-    // [fs.file_status.cons], constructors and destructor
     file_status() noexcept : file_status(file_type::none) {}
     explicit file_status(file_type ft,
                          perms prms = perms::unknown) noexcept;
     file_status(const file_status&) noexcept = default;
     file_status(file_status&&) noexcept = default;
     ~file_status();
-    // assignments:
     file_status& operator=(const file_status&) noexcept = default;
     file_status& operator=(file_status&&) noexcept = default;
-    // [fs.file_status.mods], modifiers
     void       type(file_type ft) noexcept;
     void       permissions(perms prms) noexcept;
-    // [fs.file_status.obs], observers
     file_type  type() const noexcept;
     perms      permissions() const noexcept;
   };
 }
 ```
-#### `file_status` constructors <a id="fs.file_status.cons">[[fs.file_status.cons]]</a>
 ``` cpp
 explicit file_status(file_type ft, perms prms = perms::unknown) noexcept;
 ```
-*Postconditions:* `type() == ft` and `permissions() == prms`.
-#### `file_status` observers <a id="fs.file_status.obs">[[fs.file_status.obs]]</a>
 ``` cpp
 file_type type() const noexcept;
 ```
@@ -2102,53 +2011,53 @@ perms permissions() const noexcept;
 *Returns:* The value of `permissions()` specified by the postconditions
 of the most recent call to a constructor, `operator=`, or
 `permissions(perms)` function.
-#### `file_status` modifiers <a id="fs.file_status.mods">[[fs.file_status.mods]]</a>
 ``` cpp
 void type(file_type ft) noexcept;
 ```
-*Postconditions:* `type() == ft`.
 ``` cpp
 void permissions(perms prms) noexcept;
 ```
-*Postconditions:* `permissions() == prms`.
-### Class `directory_entry` <a id="fs.class.directory_entry">[[fs.class.directory_entry]]</a>
 ``` cpp
 namespace std::filesystem {
   class directory_entry {
   public:
     // [fs.dir.entry.cons], constructors and destructor
     directory_entry() noexcept = default;
     directory_entry(const directory_entry&) = default;
     directory_entry(directory_entry&&) noexcept = default;
-    explicit directory_entry(const path& p);
-    directory_entry(const path& p, error_code& ec);
     ~directory_entry();
-    // assignments:
     directory_entry& operator=(const directory_entry&) = default;
     directory_entry& operator=(directory_entry&&) noexcept = default;
     // [fs.dir.entry.mods], modifiers
-    void assign(const path& p);
-    void assign(const path& p, error_code& ec);
-    void replace_filename(const path& p);
-    void replace_filename(const path& p, error_code& ec);
     void refresh();
     void refresh(error_code& ec) noexcept;
     // [fs.dir.entry.obs], observers
-    const path& path() const noexcept;
-    operator const path&() const noexcept;
     bool exists() const;
     bool exists(error_code& ec) const noexcept;
     bool is_block_file() const;
     bool is_block_file(error_code& ec) const noexcept;
     bool is_character_file() const;
@@ -2174,36 +2083,32 @@ namespace std::filesystem {
     file_status status() const;
     file_status status(error_code& ec) const noexcept;
     file_status symlink_status() const;
     file_status symlink_status(error_code& ec) const noexcept;
-    bool operator< (const directory_entry& rhs) const noexcept;
     bool operator==(const directory_entry& rhs) const noexcept;
- bool operator!=(const directory_entry& rhs) const noexcept;
-    bool operator<=(const directory_entry& rhs) const noexcept;
-    bool operator> (const directory_entry& rhs) const noexcept;
-    bool operator>=(const directory_entry& rhs) const noexcept;
   private:
-    path pathobject; // exposition only
     friend class directory_iterator;    // exposition only
   };
 }
 ```
 A `directory_entry` object stores a `path` object and may store
 additional objects for file attributes such as hard link count, status,
 symlink status, file size, and last write time.
-Implementations are encouraged to store such additional file attributes
-during directory iteration if their values are available and storing the
-values would allow the implementation to eliminate file system accesses
-by `directory_entry` observer functions ([[fs.op.funcs]]). Such stored
-file attribute values are said to be *cached*.
-[*Note 1*: For purposes of exposition, class `directory_iterator` (
-[[fs.class.directory_iterator]]) is shown above as a friend of class
 `directory_entry`. Friendship allows the `directory_iterator`
 implementation to cache already available attribute values directly into
 a `directory_entry` object without the cost of an unneeded call to
 `refresh()`. — *end note*]
@@ -2235,41 +2140,40 @@ so will not result in a potentially expensive call to the
 `std::filesystem::last_write_time` function. The code is portable to any
 implementation, regardless of whether or not it employs caching.
 — *end example*]
-#### `directory_entry` constructors <a id="fs.dir.entry.cons">[[fs.dir.entry.cons]]</a>
 ``` cpp
-explicit directory_entry(const path& p);
-directory_entry(const path& p, error_code& ec);
 ```
-*Effects:* Constructs an object of type `directory_entry`, then
-`refresh()` or `refresh(ec)`, respectively.
-*Postconditions:* `path() == p` if no error occurs, otherwise
-`path() == std::filesystem::path()`.
 *Throws:* As specified in  [[fs.err.report]].
-#### `directory_entry` modifiers <a id="fs.dir.entry.mods">[[fs.dir.entry.mods]]</a>
 ``` cpp
-void assign(const path& p);
-void assign(const path& p, error_code& ec);
 ```
 *Effects:* Equivalent to `pathobject = p`, then `refresh()` or
 `refresh(ec)`, respectively. If an error occurs, the values of any
 cached attributes are unspecified.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
-void replace_filename(const path& p);
-void replace_filename(const path& p, error_code& ec);
 ```
 *Effects:* Equivalent to `pathobject.replace_filename(p)`, then
 `refresh()` or `refresh(ec)`, respectively. If an error occurs, the
 values of any cached attributes are unspecified.
@@ -2281,121 +2185,121 @@ void refresh();
 void refresh(error_code& ec) noexcept;
 ```
 *Effects:* Stores the current values of any cached attributes of the
 file `p` resolves to. If an error occurs, an error is
-reported ([[fs.err.report]]) and the values of any cached attributes
-are unspecified.
 *Throws:* As specified in  [[fs.err.report]].
-[*Note 1*: Implementations of
-`directory_iterator` ([[fs.class.directory_iterator]]) are prohibited
-from directly or indirectly calling the `refresh` function since it must
-access the external file system, and the objective of caching is to
-avoid unnecessary file system accesses. — *end note*]
-#### `directory_entry` observers <a id="fs.dir.entry.obs">[[fs.dir.entry.obs]]</a>
 Unqualified function names in the *Returns:* elements of the
 `directory_entry` observers described below refer to members of the
 `std::filesystem` namespace.
 ``` cpp
-const path& path() const noexcept;
-operator const path&() const noexcept;
 ```
 *Returns:* `pathobject`.
 ``` cpp
 bool exists() const;
 bool exists(error_code& ec) const noexcept;
 ```
-*Returns:* `exists(this->status())` or `exists(this->status(), ec)`,
 respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_block_file() const;
 bool is_block_file(error_code& ec) const noexcept;
 ```
 *Returns:* `is_block_file(this->status())` or
-`is_block_file(this->status(), ec)`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_character_file() const;
 bool is_character_file(error_code& ec) const noexcept;
 ```
 *Returns:* `is_character_file(this->status())` or
-`is_character_file(this->status(), ec)`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_directory() const;
 bool is_directory(error_code& ec) const noexcept;
 ```
 *Returns:* `is_directory(this->status())` or
-`is_directory(this->status(), ec)`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_fifo() const;
 bool is_fifo(error_code& ec) const noexcept;
 ```
-*Returns:* `is_fifo(this->status())` or `is_fifo(this->status(), ec)`,
 respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_other() const;
 bool is_other(error_code& ec) const noexcept;
 ```
-*Returns:* `is_other(this->status())` or `is_other(this->status(), ec)`,
 respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_regular_file() const;
 bool is_regular_file(error_code& ec) const noexcept;
 ```
 *Returns:* `is_regular_file(this->status())` or
-`is_regular_file(this->status(), ec)`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_socket() const;
 bool is_socket(error_code& ec) const noexcept;
 ```
-*Returns:* `is_socket(this->status())` or
-`is_socket(this->status(), ec)`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_symlink() const;
 bool is_symlink(error_code& ec) const noexcept;
 ```
 *Returns:* `is_symlink(this->symlink_status())` or
-`is_symlink(this->symlink_status(), ec)`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 uintmax_t file_size() const;
@@ -2454,49 +2358,24 @@ bool operator==(const directory_entry& rhs) const noexcept;
 ```
 *Returns:* `pathobject == rhs.pathobject`.
 ``` cpp
-bool operator!=(const directory_entry& rhs) const noexcept;
 ```
-*Returns:* `pathobject != rhs.pathobject`.
-``` cpp
-bool operator< (const directory_entry& rhs) const noexcept;
-```
-*Returns:* `pathobject < rhs.pathobject`.
-``` cpp
-bool operator<=(const directory_entry& rhs) const noexcept;
-```
-*Returns:* `pathobject <= rhs.pathobject`.
-``` cpp
-bool operator> (const directory_entry& rhs) const noexcept;
-```
-*Returns:* `pathobject > rhs.pathobject`.
-``` cpp
-bool operator>=(const directory_entry& rhs) const noexcept;
-```
-*Returns:* `pathobject >= rhs.pathobject`.
-### Class `directory_iterator` <a id="fs.class.directory_iterator">[[fs.class.directory_iterator]]</a>
 An object of type `directory_iterator` provides an iterator for a
 sequence of `directory_entry` elements representing the path and any
-cached attribute values ([[fs.class.directory_entry]]) for each file in
-a directory or in an *implementation-defined* directory-like file type.
 [*Note 1*: For iteration into sub-directories, see class
-`recursive_directory_iterator` (
-[[fs.class.rec.dir.itr]]). — *end note*]
 ``` cpp
 namespace std::filesystem {
   class directory_iterator {
   public:
@@ -2508,32 +2387,32 @@ namespace std::filesystem {
     // [fs.dir.itr.members], member functions
     directory_iterator() noexcept;
     explicit directory_iterator(const path& p);
     directory_iterator(const path& p, directory_options options);
-    directory_iterator(const path& p, error_code& ec) noexcept;
     directory_iterator(const path& p, directory_options options,
-                       error_code& ec) noexcept;
     directory_iterator(const directory_iterator& rhs);
     directory_iterator(directory_iterator&& rhs) noexcept;
     ~directory_iterator();
     directory_iterator& operator=(const directory_iterator& rhs);
     directory_iterator& operator=(directory_iterator&& rhs) noexcept;
     const directory_entry& operator*() const;
     const directory_entry* operator->() const;
     directory_iterator&    operator++();
-    directory_iterator&    increment(error_code& ec) noexcept;
     // other members as required by [input.iterators], input iterators
   };
 }
 ```
-`directory_iterator` satisfies the requirements of an input iterator (
-[[input.iterators]]).
 If an iterator of type `directory_iterator` reports an error or is
 advanced past the last directory element, that iterator shall become
 equal to the end iterator value. The `directory_iterator` default
 constructor shall create an iterator equal to the end iterator value,
@@ -2549,24 +2428,24 @@ object obtained by dereferencing a `directory_iterator` is a reference
 to a `path` object composed of the directory argument from which the
 iterator was constructed with filename of the directory entry appended
 as if by `operator/=`.
 Directory iteration shall not yield directory entries for the current
-(*dot*) and parent (*dot-dot*) directories.
 The order of directory entries obtained by dereferencing successive
 increments of a `directory_iterator` is unspecified.
 Constructors and non-const `directory_iterator` member functions store
-the values of any cached attributes ([[fs.class.directory_entry]]) in
-the `directory_entry` element returned by `operator*()`.
 `directory_iterator` member functions shall not directly or indirectly
 call any `directory_entry` `refresh` function.
 [*Note 2*: The exact mechanism for storing cached attribute values is
 not exposed to users. For exposition, class `directory_iterator` is
-shown in [[fs.class.directory_entry]] as a friend of class
 `directory_entry`. — *end note*]
 [*Note 3*: Programs performing directory iteration may wish to test if
 the path obtained by dereferencing a directory iterator actually exists.
 It could be a symbolic link to a non-existent file. Programs recursively
@@ -2577,23 +2456,23 @@ may wish to avoid following symbolic links. — *end note*]
 construction of a `directory_iterator` for the directory, it is
 unspecified whether or not subsequently incrementing the iterator will
 ever result in an iterator referencing the removed or added directory
 entry. See POSIX `readdir_r`. — *end note*]
-#### `directory_iterator` members <a id="fs.dir.itr.members">[[fs.dir.itr.members]]</a>
 ``` cpp
 directory_iterator() noexcept;
 ```
 *Effects:* Constructs the end iterator.
 ``` cpp
 explicit directory_iterator(const path& p);
 directory_iterator(const path& p, directory_options options);
-directory_iterator(const path& p, error_code& ec) noexcept;
-directory_iterator(const path& p, directory_options options, error_code& ec) noexcept;
 ```
 *Effects:* For the directory that `p` resolves to, constructs an
 iterator for the first element in a sequence of `directory_entry`
 elements representing the files in the directory, if any; otherwise the
@@ -2616,39 +2495,37 @@ error.
 ``` cpp
 directory_iterator(const directory_iterator& rhs);
 directory_iterator(directory_iterator&& rhs) noexcept;
 ```
-*Effects:* Constructs an object of class `directory_iterator`.
-*Postconditions:* `*this` has the original value of `rhs`.
 ``` cpp
 directory_iterator& operator=(const directory_iterator& rhs);
 directory_iterator& operator=(directory_iterator&& rhs) noexcept;
 ```
 *Effects:* If `*this` and `rhs` are the same object, the member has no
 effect.
-*Postconditions:* `*this` has the original value of `rhs`.
 *Returns:* `*this`.
 ``` cpp
 directory_iterator& operator++();
-directory_iterator& increment(error_code& ec) noexcept;
 ```
 *Effects:* As specified for the prefix increment operation of Input
-iterators ([[input.iterators]]).
 *Returns:* `*this`.
 *Throws:* As specified in  [[fs.err.report]].
-#### `directory_iterator` non-member functions <a id="fs.dir.itr.nonmembers">[[fs.dir.itr.nonmembers]]</a>
 These functions enable range access for `directory_iterator`.
 ``` cpp
 directory_iterator begin(directory_iterator iter) noexcept;
@@ -2682,12 +2559,12 @@ namespace std::filesystem {
     // [fs.rec.dir.itr.members], constructors and destructor
     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) noexcept;
-    recursive_directory_iterator(const path& p, error_code& ec) noexcept;
     recursive_directory_iterator(const recursive_directory_iterator& rhs);
     recursive_directory_iterator(recursive_directory_iterator&& rhs) noexcept;
     ~recursive_directory_iterator();
     // [fs.rec.dir.itr.members], observers
@@ -2703,11 +2580,11 @@ namespace std::filesystem {
       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) noexcept;
     void pop();
     void pop(error_code& ec);
     void disable_recursion_pending();
@@ -2724,38 +2601,38 @@ 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 the end iterator may be unreachable. — *end note*]
-#### `recursive_directory_iterator` members <a id="fs.rec.dir.itr.members">[[fs.rec.dir.itr.members]]</a>
 ``` cpp
 recursive_directory_iterator() noexcept;
 ```
 *Effects:* Constructs the end iterator.
 ``` cpp
 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) noexcept;
-recursive_directory_iterator(const path& p, error_code& ec) noexcept;
 ```
-*Effects:* Constructs a iterator representing the first entry in the
-directory `p` resolves to, if any; otherwise, the end iterator. However,
-if
 ``` cpp
 (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`.
 *Throws:* As specified in  [[fs.err.report]].
@@ -2763,42 +2640,38 @@ error.
 `recursive_directory_iterator(".")` rather than
 `recursive_directory_iterator("")`. — *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*]
 ``` cpp
 recursive_directory_iterator(const recursive_directory_iterator& rhs);
 ```
-*Effects:* Constructs an object of class `recursive_directory_iterator`.
-*Postconditions:*
 - `options() == rhs.options()`
 - `depth() == rhs.depth()`
 - `recursion_pending() == rhs.recursion_pending()`
 ``` cpp
 recursive_directory_iterator(recursive_directory_iterator&& rhs) noexcept;
 ```
-*Effects:* Constructs an object of class `recursive_directory_iterator`.
-*Postconditions:* `options()`, `depth()`, and `recursion_pending()` have
-the values that `rhs.options()`, `rhs.depth()`, and
 `rhs.recursion_pending()`, respectively, had before the function call.
 ``` cpp
 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()`
@@ -2809,12 +2682,12 @@ recursive_directory_iterator& operator=(recursive_directory_iterator&& rhs) noex
 ```
 *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.
 *Returns:* `*this`.
 ``` cpp
@@ -2847,15 +2720,15 @@ subsequent to the prior construction or increment operation, otherwise
 *Throws:* Nothing.
 ``` cpp
 recursive_directory_iterator& operator++();
-recursive_directory_iterator& increment(error_code& ec) noexcept;
 ```
 *Effects:* As specified for the prefix increment operation of Input
-iterators ([[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
@@ -2889,20 +2762,23 @@ void pop(error_code& ec);
 directory currently being iterated over, and continue iteration over the
 parent directory.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 void disable_recursion_pending();
 ```
-*Postconditions:* `recursion_pending() == false`.
 [*Note 4*: `disable_recursion_pending``()` is used to prevent unwanted
 recursion into a directory. — *end note*]
-#### `recursive_directory_iterator` non-member functions <a id="fs.rec.dir.itr.nonmembers">[[fs.rec.dir.itr.nonmembers]]</a>
 These functions enable use of `recursive_directory_iterator` with
 range-based for statements.
 ``` cpp
@@ -2921,11 +2797,11 @@ recursive_directory_iterator end(const recursive_directory_iterator&) noexcept;
 Filesystem operation functions query or modify files, including
 directories, in external storage.
 [*Note 1*: Because hardware failures, network failures, file system
-races ([[fs.def.race]]), and many other kinds of errors occur
 frequently in file system operations, users should be aware that any
 filesystem operation function, no matter how apparently innocuous, may
 encounter an error; see  [[fs.err.report]]. — *end note*]
 #### Absolute <a id="fs.op.absolute">[[fs.op.absolute]]</a>
@@ -2934,11 +2810,11 @@ encounter an error; see  [[fs.err.report]]. — *end note*]
 path absolute(const path& p);
 path absolute(const path& p, error_code& ec);
 ```
 *Effects:* Composes an absolute path referencing the same file system
-location as `p` according to the operating system ([[fs.conform.os]]).
 *Returns:* The composed path. The signature with argument `ec` returns
 `path()` if an error occurs.
 [*Note 1*: For the returned path, `rp`, `rp.is_absolute()` is `true`
@@ -2946,11 +2822,11 @@ unless an error occurs. — *end note*]
 *Throws:* As specified in  [[fs.err.report]].
 [*Note 2*: To resolve symlinks, or perform other sanitization which
 might require queries to secondary storage, such as hard disks, consider
-`canonical` ([[fs.op.canonical]]). — *end note*]
 [*Note 3*: Implementations are strongly encouraged to not query
 secondary storage, and not consider `!exists(p)` an
 error. — *end note*]
@@ -2960,22 +2836,19 @@ simply `current_path()/p`. For Windows-based operating systems,
 `GetFullPathNameW`. — *end example*]
 #### Canonical <a id="fs.op.canonical">[[fs.op.canonical]]</a>
 ``` cpp
-path canonical(const path& p, const path& base = current_path());
 path canonical(const path& p, error_code& ec);
-path canonical(const path& p, const path& base, error_code& ec);
 ```
-*Effects:* Converts `p`, which must exist, to an absolute path that has
-no symbolic link, *dot*, or *dot-dot* elements in its pathname in the
-generic format.
 *Returns:* A path that refers to the same file system object as
-`absolute(p, base)`. For the overload without a `base` argument, `base`
-is `current_path()`. Signatures with argument `ec` return `path()` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
 *Remarks:* `!exists(p)` is an error.
@@ -2987,23 +2860,23 @@ void copy(const path& from, const path& to);
 ```
 *Effects:* Equivalent to `copy(from, to, copy_options::none)`.
 ``` cpp
-void copy(const path& from, const path& to, error_code& ec) noexcept;
 ```
 *Effects:* Equivalent to `copy(from, to, copy_options::none, ec)`.
 ``` cpp
 void copy(const path& from, const path& to, copy_options options);
 void copy(const path& from, const path& to, copy_options options,
-          error_code& ec) noexcept;
 ```
-*Requires:* At most one element from each option group
-([[fs.enum.copy.opts]]) is set in `options`.
 *Effects:* Before the first use of `f` and `t`:
 - If
   ``` cpp
@@ -3024,17 +2897,17 @@ void copy(const path& from, const path& to, copy_options options,
   `auto t = status(to)`.
 Effects are then as follows:
 - If `f.type()` or `t.type()` is an implementation-defined file
-  type ([[fs.enum.file_type]]), then the effects are
   *implementation-defined*.
 - Otherwise, an error is reported as specified in  [[fs.err.report]] if:
-  - `!exists(f)`, or
-  - `equivalent(from, to)`, or
-  - `is_other(f) || is_other(t)`, or
-  - `is_directory(f) && is_regular_file(t)`.
 - Otherwise, if `is_symlink(f)`, then:
   - If `(options & copy_options::skip_symlinks) != copy_options::none`
     then return.
   - Otherwise if
     ``` cpp
@@ -3054,24 +2927,36 @@ Effects are then as follows:
     `(options & copy_options::create_hard_links) != copy_options::none`,
     then create a hard link to the source file.
   - Otherwise, if `is_directory(t)`, then
     `copy_file(from, to/from.filename(), options)`.
   - Otherwise, `copy_file(from, to, options)`.
 - Otherwise, if
   ``` cpp
   is_directory(f) &&
   ((options & copy_options::recursive) != copy_options::none ||
    options == copy_options::none)
   ```
   then:
-  - If `!exists(t)`, then `create_directory(to, from)`.
   - Then, iterate over the files in `from`, as if by
     ``` cpp
     for (const directory_entry& x : directory_iterator(from))
-      copy(x.path(), to/x.path().filename(), options | copy_options::unspecified)
     ```
 - Otherwise, for the signature with argument `ec`, `ec.clear()`.
 - Otherwise, no effects.
 *Throws:* As specified in  [[fs.err.report]].
@@ -3120,62 +3005,61 @@ would result in:
     file3
 ```
 — *end example*]
-#### Copy file <a id="fs.op.copy_file">[[fs.op.copy_file]]</a>
 ``` cpp
 bool copy_file(const path& from, const path& to);
-bool copy_file(const path& from, const path& to, error_code& ec) noexcept;
 ```
 *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]].
 ``` cpp
 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) noexcept;
 ```
-*Requires:* At most one element from each option group
-([[fs.enum.copy.opts]]) is set in `options`.
 *Effects:* As follows:
-- Report a file already exists error as specified in  [[fs.err.report]]
- if:
-  - `!is_regular_file(from)`, or
-  - `exists(to)` and `!is_regular_file(to)`, or
-  - `exists(to)` and `equivalent(from, to)`, or
-  - `exists(to)` and
     ``` cpp
     (options & (copy_options::skip_existing |
                 copy_options::overwrite_existing |
                 copy_options::update_existing)) == copy_options::none
     ```
 - Otherwise, copy the contents and attributes of the file `from`
   resolves to, to the file `to` resolves to, if:
-  - `!exists(to)`, or
   - `(options & copy_options::overwrite_existing) != copy_options::none`,
     or
   - `(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]]).
 - 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)`.
-#### Copy symlink <a id="fs.op.copy_symlink">[[fs.op.copy_symlink]]</a>
 ``` cpp
 void copy_symlink(const path& existing_symlink, const path& new_symlink);
 void copy_symlink(const path& existing_symlink, const path& new_symlink,
                   error_code& ec) noexcept;
@@ -3187,86 +3071,78 @@ void copy_symlink(const path& existing_symlink, const path& new_symlink,
 respectively, where in each case *`function`* is `create_symlink` or
 `create_directory_symlink` as appropriate.
 *Throws:* As specified in  [[fs.err.report]].
-#### Create directories <a id="fs.op.create_directories">[[fs.op.create_directories]]</a>
 ``` cpp
 bool create_directories(const path& p);
-bool create_directories(const path& p, error_code& ec) noexcept;
 ```
-*Effects:* Establishes the postcondition by calling `create_directory()`
-for any element of `p` that does not exist.
-*Postconditions:* `is_directory(p)`.
-*Returns:* `true` if a new directory was created, otherwise `false`. The
-signature with argument `ec` returns `false` if an error occurs.
-*Throws:* As specified in  [[fs.err.report]].
-*Complexity:* 𝑂(n) where *n* is the number of elements of `p` that do
 not exist.
-#### Create directory <a id="fs.op.create_directory">[[fs.op.create_directory]]</a>
 ``` cpp
 bool create_directory(const path& p);
 bool create_directory(const path& p, error_code& ec) noexcept;
 ```
-*Effects:* Establishes the postcondition by attempting to create the
-directory `p` resolves to, as if by POSIX `mkdir()` with a second
-argument of `static_cast<int>(perms::all)`. Creation failure because `p`
-resolves to an existing directory shall not be treated as an error.
-*Postconditions:* `is_directory(p)`.
-*Returns:* `true` if a new directory was created, otherwise `false`. The
-signature with argument `ec` returns `false` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool create_directory(const path& p, const path& existing_p);
 bool create_directory(const path& p, const path& existing_p, error_code& ec) noexcept;
 ```
-*Effects:* Establishes the postcondition by attempting to create the
-directory `p` resolves to, with attributes copied from directory
-`existing_p`. The set of attributes copied is operating system
-dependent. Creation failure because `p` resolves to an existing
-directory shall not be treated as an error.
 [*Note 1*: For POSIX-based operating systems, the attributes are those
 copied by native API `stat(existing_p.c_str(), &attributes_stat)`
 followed by `mkdir(p.c_str(), attributes_stat.st_mode)`. For
 Windows-based operating systems, the attributes are those copied by
 native API
 `CreateDirectoryExW(existing_p.c_str(), p.c_str(), 0)`. — *end note*]
-*Postconditions:* `is_directory(p)`.
-*Returns:* `true` if a new directory was created, otherwise `false`. The
-signature with argument `ec` returns `false` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Create directory symlink <a id="fs.op.create_dir_symlk">[[fs.op.create_dir_symlk]]</a>
 ``` cpp
 void create_directory_symlink(const path& to, const path& new_symlink);
 void create_directory_symlink(const path& to, const path& new_symlink,
                               error_code& ec) noexcept;
 ```
 *Effects:* Establishes the postcondition, as if by POSIX `symlink()`.
-*Postconditions:* `new_symlink` resolves to a symbolic link file that
-contains an unspecified representation of `to`.
 *Throws:* As specified in  [[fs.err.report]].
 [*Note 1*: Some operating systems require symlink creation to identify
 that the link is to a directory. Portable code should use
@@ -3276,21 +3152,21 @@ that the link is to a directory. Portable code should use
 [*Note 2*: Some operating systems do not support symbolic links at all
 or support them only for regular files. Some file systems (such as the
 FAT file system) do not support symbolic links regardless of the
 operating system. — *end note*]
-#### Create hard link <a id="fs.op.create_hard_lk">[[fs.op.create_hard_lk]]</a>
 ``` cpp
 void create_hard_link(const path& to, const path& new_hard_link);
 void create_hard_link(const path& to, const path& new_hard_link,
                                       error_code& ec) noexcept;
 ```
 *Effects:* Establishes the postcondition, as if by POSIX `link()`.
-*Postconditions:*
 - `exists(to) && exists(new_hard_link) && equivalent(to, new_hard_link)`
 - The contents of the file or directory `to` resolves to are unchanged.
 *Throws:* As specified in  [[fs.err.report]].
@@ -3299,31 +3175,31 @@ void create_hard_link(const path& to, const path& new_hard_link,
 support them only for regular files. Some file systems (such as the FAT
 file system) do not support hard links regardless of the operating
 system. Some file systems limit the number of links per
 file. — *end note*]
-#### Create symlink <a id="fs.op.create_symlink">[[fs.op.create_symlink]]</a>
 ``` cpp
 void create_symlink(const path& to, const path& new_symlink);
 void create_symlink(const path& to, const path& new_symlink,
                     error_code& ec) noexcept;
 ```
 *Effects:* Establishes the postcondition, as if by POSIX `symlink()`.
-*Postconditions:* `new_symlink` resolves to a symbolic link file that
-contains an unspecified representation of `to`.
 *Throws:* As specified in  [[fs.err.report]].
 [*Note 1*: Some operating systems do not support symbolic links at all
 or support them only for regular files. Some file systems (such as the
 FAT file system) do not support symbolic links regardless of the
 operating system. — *end note*]
-#### Current path <a id="fs.op.current_path">[[fs.op.current_path]]</a>
 ``` cpp
 path current_path();
 path current_path(error_code& ec);
 ```
@@ -3341,22 +3217,21 @@ resolution for relative paths.
 [*Note 1*: The `current_path()` name was chosen to emphasize that the
 returned value is a path, not just a single directory
 name. — *end note*]
 [*Note 2*: The current path as returned by many operating systems is a
-dangerous global variable. It may be changed unexpectedly by a
-third-party or system library functions, or by another
-thread. — *end note*]
 ``` cpp
 void current_path(const path& p);
 void current_path(const path& p, error_code& ec) noexcept;
 ```
 *Effects:* Establishes the postcondition, as if by POSIX `chdir()`.
-*Postconditions:* `equivalent(p, current_path())`.
 *Throws:* As specified in  [[fs.err.report]].
 [*Note 3*: The current path for many operating systems is a dangerous
 global state. It may be changed unexpectedly by a third-party or system
@@ -3367,26 +3242,22 @@ library functions, or by another thread. — *end note*]
 ``` cpp
 bool equivalent(const path& p1, const path& p2);
 bool equivalent(const path& p1, const path& p2, error_code& ec) noexcept;
 ```
-Let `s1` and `s2` be `file_status`s, determined as if by `status(p1)`
-and `status(p2)`, respectively.
-*Effects:* Determines `s1` and `s2`. If
-`(!exists(s1) && !exists(s2)) || (is_other(s1) && is_other(s2))` an
-error is reported ([[fs.err.report]]).
-*Returns:* `true`, if `s1 == s2` and `p1` and `p2` resolve to the same
-file system entity, else `false`. The signature with argument `ec`
-returns `false` if an error occurs.
 Two paths are considered to resolve to the same file system entity if
 two candidate entities reside on the same device at the same location.
-This is determined as if by the values of the POSIX `stat` structure,
-obtained as if by `stat()` for the two paths, having equal `st_dev`
-values and equal `st_ino` values.
 *Throws:* As specified in  [[fs.err.report]].
 #### Exists <a id="fs.op.exists">[[fs.op.exists]]</a>
@@ -3409,31 +3280,33 @@ Let `s` be a `file_status`, determined as if by `status(p)` or
 *Returns:* `exists(s)`.
 *Throws:* As specified in  [[fs.err.report]].
-#### File size <a id="fs.op.file_size">[[fs.op.file_size]]</a>
 ``` cpp
 uintmax_t file_size(const path& p);
 uintmax_t file_size(const path& p, error_code& ec) noexcept;
 ```
 *Returns:*
-- If `!exists(p)` an error is reported ([[fs.err.report]]).
-- Otherwise, if `is_regular_file(p)`, the size in bytes of the file `p`
- resolves to, determined as if by the value of the POSIX `stat`
-  structure member `st_size` obtained as if by POSIX `stat()`.
 - Otherwise, the result is *implementation-defined*.
 The signature with argument `ec` returns `static_cast<uintmax_t>(-1)` if
 an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Hard link count <a id="fs.op.hard_lk_ct">[[fs.op.hard_lk_ct]]</a>
 ``` cpp
 uintmax_t hard_link_count(const path& p);
 uintmax_t hard_link_count(const path& p, error_code& ec) noexcept;
 ```
@@ -3441,11 +3314,11 @@ uintmax_t hard_link_count(const path& p, error_code& ec) noexcept;
 *Returns:* The number of hard links for `p`. The signature with argument
 `ec` returns `static_cast<uintmax_t>(-1)` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Is block file <a id="fs.op.is_block_file">[[fs.op.is_block_file]]</a>
 ``` cpp
 bool is_block_file(file_status s) noexcept;
 ```
@@ -3460,11 +3333,11 @@ bool is_block_file(const path& p, error_code& ec) noexcept;
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Is character file <a id="fs.op.is_char_file">[[fs.op.is_char_file]]</a>
 ``` cpp
 bool is_character_file(file_status s) noexcept;
 ```
@@ -3479,11 +3352,11 @@ bool is_character_file(const path& p, error_code& ec) noexcept;
 `is_character_file(status(p, ec))`, respectively.
 The signature with argument `ec` returns `false` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Is directory <a id="fs.op.is_directory">[[fs.op.is_directory]]</a>
 ``` cpp
 bool is_directory(file_status s) noexcept;
 ```
@@ -3498,15 +3371,15 @@ bool is_directory(const path& p, error_code& ec) noexcept;
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Is empty <a id="fs.op.is_empty">[[fs.op.is_empty]]</a>
 ``` cpp
 bool is_empty(const path& p);
-bool is_empty(const path& p, error_code& ec) noexcept;
 ```
 *Effects:*
 - Determine `file_status s`, as if by `status(p)` or `status(p, ec)`,
@@ -3526,11 +3399,11 @@ bool is_empty(const path& p, error_code& ec) noexcept;
     occurred.
   - Otherwise, return `sz == 0`.
 *Throws:* As specified in  [[fs.err.report]].
-#### Is fifo <a id="fs.op.is_fifo">[[fs.op.is_fifo]]</a>
 ``` cpp
 bool is_fifo(file_status s) noexcept;
 ```
@@ -3545,11 +3418,11 @@ bool is_fifo(const path& p, error_code& ec) noexcept;
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Is other <a id="fs.op.is_other">[[fs.op.is_other]]</a>
 ``` cpp
 bool is_other(file_status s) noexcept;
 ```
@@ -3565,11 +3438,11 @@ bool is_other(const path& p, error_code& ec) noexcept;
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Is regular file <a id="fs.op.is_regular_file">[[fs.op.is_regular_file]]</a>
 ``` cpp
 bool is_regular_file(file_status s) noexcept;
 ```
@@ -3580,11 +3453,11 @@ bool is_regular_file(const path& p);
 ```
 *Returns:* `is_regular_file(status(p))`.
 *Throws:* `filesystem_error` if `status(p)` would throw
-`filesystem_error.`
 ``` cpp
 bool is_regular_file(const path& p, error_code& ec) noexcept;
 ```
@@ -3595,11 +3468,11 @@ bool is_regular_file(const path& p, error_code& ec) noexcept;
 between cases, call the `status` function directly. — *end note*]
 *Returns:* `is_regular_file(status(p, ec))`. Returns `false` if an error
 occurs.
-#### Is socket <a id="fs.op.is_socket">[[fs.op.is_socket]]</a>
 ``` cpp
 bool is_socket(file_status s) noexcept;
 ```
@@ -3614,11 +3487,11 @@ bool is_socket(const path& p, error_code& ec) noexcept;
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Is symlink <a id="fs.op.is_symlink">[[fs.op.is_symlink]]</a>
 ``` cpp
 bool is_symlink(file_status s) noexcept;
 ```
@@ -3633,20 +3506,20 @@ bool is_symlink(const path& p, error_code& ec) noexcept;
 `is_symlink(symlink_status(p, ec))`, respectively. The signature with
 argument `ec` returns `false` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Last write time <a id="fs.op.last_write_time">[[fs.op.last_write_time]]</a>
 ``` cpp
 file_time_type last_write_time(const path& p);
 file_time_type last_write_time(const path& p, error_code& ec) noexcept;
 ```
 *Returns:* The time of last data modification of `p`, determined as if
-by the value of the POSIX `stat` structure member `st_mtime` obtained as
-if by POSIX `stat()`. The signature with argument `ec` returns
 `file_time_type::min()` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
@@ -3670,11 +3543,11 @@ granularity. — *end note*]
 void permissions(const path& p, perms prms, perm_options opts=perm_options::replace);
 void permissions(const path& p, perms prms, error_code& ec) noexcept;
 void permissions(const path& p, perms prms, perm_options opts, error_code& ec);
 ```
-*Requires:* Exactly one of the `perm_options` constants `replace`,
 `add`, or `remove` is present in `opts`.
 *Remarks:* The second signature behaves as if it had an additional
 parameter `perm_options` `opts` with an argument of
 `perm_options::replace`.
@@ -3718,11 +3591,11 @@ weakly_canonical(p, ec).lexically_proximate(weakly_canonical(base, ec));
 or `path()` at the first error occurrence, if any.
 *Throws:* As specified in  [[fs.err.report]].
-#### Read symlink <a id="fs.op.read_symlink">[[fs.op.read_symlink]]</a>
 ``` cpp
 path read_symlink(const path& p);
 path read_symlink(const path& p, error_code& ec);
 ```
@@ -3778,31 +3651,31 @@ bool remove(const path& p, error_code& ec) noexcept;
 as if by POSIX `remove()`.
 [*Note 1*: A symbolic link is itself removed, rather than the file it
 resolves to. — *end note*]
-*Postconditions:* `!exists(symlink_status(p))`.
 *Returns:* `false` if `p` did not exist, otherwise `true`. The signature
 with argument `ec` returns `false` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
-#### Remove all <a id="fs.op.remove_all">[[fs.op.remove_all]]</a>
 ``` cpp
 uintmax_t remove_all(const path& p);
-uintmax_t remove_all(const path& p, error_code& ec) noexcept;
 ```
 *Effects:* Recursively deletes the contents of `p` if it exists, then
 deletes file `p` itself, as if by POSIX `remove()`.
 [*Note 1*: A symbolic link is itself removed, rather than the file it
 resolves to. — *end note*]
-*Postconditions:* `!exists(symlink_status(p))`.
 *Returns:* The number of files removed. The signature with argument `ec`
 returns `static_cast< uintmax_t>(-1)` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
@@ -3831,23 +3704,22 @@ A symbolic link is itself renamed, rather than the file it resolves to.
 — *end note*]
 *Throws:* As specified in  [[fs.err.report]].
-#### Resize file <a id="fs.op.resize_file">[[fs.op.resize_file]]</a>
 ``` cpp
 void resize_file(const path& p, uintmax_t new_size);
 void resize_file(const path& p, uintmax_t new_size, error_code& ec) noexcept;
 ```
-*Postconditions:* `file_size(p) == new_size`.
 *Throws:* As specified in  [[fs.err.report]].
-*Remarks:* Achieves its postconditions as if by POSIX `truncate()`.
 #### Space <a id="fs.op.space">[[fs.op.space]]</a>
 ``` cpp
 space_info space(const path& p);
 space_info space(const path& p, error_code& ec) noexcept;
@@ -3946,27 +3818,27 @@ determined as if by converting the `st_mode` member of the obtained
   - Otherwise, if the attributes indicate a fifo or pipe file, as if by
     POSIX `S_ISFIFO`, returns `file_status(file_type::fifo, prms)`.
   - Otherwise, if the attributes indicate a socket, as if by POSIX
     `S_ISSOCK`, returns `file_status(file_type::socket, prms)`.
   - 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.
   - 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.
-#### Status known <a id="fs.op.status_known">[[fs.op.status_known]]</a>
 ``` cpp
 bool status_known(file_status s) noexcept;
 ```
 *Returns:* `s.type() != file_type::none`.
-#### Symlink status <a id="fs.op.symlink_status">[[fs.op.symlink_status]]</a>
 ``` cpp
 file_status symlink_status(const path& p);
 file_status symlink_status(const path& p, error_code& ec) noexcept;
 ```
@@ -3986,20 +3858,23 @@ indicate a symbolic link, as if by POSIX `S_ISLNK`, returns
 *Remarks:* Pathname resolution terminates if `p` names a symbolic link.
 *Throws:* As specified in  [[fs.err.report]].
-#### Temporary directory path <a id="fs.op.temp_dir_path">[[fs.op.temp_dir_path]]</a>
 ``` cpp
 path temp_directory_path();
 path temp_directory_path(error_code& ec);
 ```
-*Returns:* An unspecifed directory path suitable for temporary files. An
-error shall be reported if `!exists(p) || !is_directory(p)`, where `p`
-is the path to be returned. The signature with argument `ec` returns
 `path()` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
 [*Example 1*: For POSIX-based operating systems, an implementation
@@ -4007,34 +3882,31 @@ might return the path supplied by the first environment variable found
 in the list TMPDIR, TMP, TEMP, TEMPDIR, or if none of these are found,
 `"/tmp"`. For Windows-based operating systems, an implementation might
 return the path reported by the Windows `GetTempPath` API
 function. — *end example*]
-#### Weakly canonical <a id="fs.op.weakly_canonical">[[fs.op.weakly_canonical]]</a>
 ``` cpp
 path weakly_canonical(const path& p);
 path weakly_canonical(const path& p, error_code& ec);
 ```
 *Returns:* `p` with symlinks resolved and the result
-normalized ([[fs.def.normal.form]]).
 *Effects:* Using `status(p)` or `status(p, ec)`, respectively, to
 determine existence, return a path composed by `operator/=` from the
-result of calling `canonical()` without a `base` argument and with a
-path argument composed of the leading elements of `p` that exist, if
-any, followed by the elements of `p` that do not exist, if any. For the
-first form, `canonical()` is called without an `error_code` argument.
-For the second form, `canonical()` is called with `ec` as an
-`error_code` argument, and `path()` is returned at the first error
-occurrence, if any.
-*Postconditions:* The returned path is in normal
-form ([[fs.def.normal.form]]).
-*Remarks:* Implementations are encouraged to avoid unnecessary
-normalization such as when `canonical` has already been called on the
-entirety of `p`.
 *Throws:* As specified in  [[fs.err.report]].

 ## File systems <a id="filesystems">[[filesystems]]</a>
 ### General <a id="fs.general">[[fs.general]]</a>
+Subclause  [[filesystems]] describes operations on file systems and
+their components, such as paths, regular files, and directories.
+A *file system* is a collection of files and their attributes.
+A *file* is an object within a file system that holds user or system
+data. Files can be written to, or read from, or both. A file has certain
+attributes, including type. File types include regular files and
+directories. Other types of files, such as symbolic links, may be
+supported by the implementation.
+A *directory* is a file within a file system that acts as a container of
+directory entries that contain information about other files, possibly
+including other directory files. The *parent directory* of a directory
+is the directory that both contains a directory entry for the given
+directory and is represented by the dot-dot filename [[fs.path.generic]]
+in the given directory. The *parent directory* of other types of files
+is a directory containing a directory entry for the file under
+discussion.
+A *link* is an object that associates a filename with a file. Several
+links can associate names with the same file. A *hard link* is a link to
+an existing file. Some file systems support multiple hard links to a
+file. If the last hard link to a file is removed, the file itself is
+removed.
+[*Note 1*: A hard link can be thought of as a shared-ownership smart
+pointer to a file. — *end note*]
+A *symbolic link* is a type of file with the property that when the file
+is encountered during pathname resolution [[fs.class.path]], a string
+stored by the file is used to modify the pathname resolution.
+[*Note 2*: Symbolic links are often called symlinks. A symbolic link
+can be thought of as a raw pointer to a file. If the file pointed to
+does not exist, the symbolic link is said to be a “dangling” symbolic
+link. — *end note*]
 ### Conformance <a id="fs.conformance">[[fs.conformance]]</a>
 Conformance is specified in terms of behavior. Ideal behavior is not
 always implementable, so the conformance subclauses take that into
 account.
 #### POSIX conformance <a id="fs.conform.9945">[[fs.conform.9945]]</a>
+Some behavior is specified by reference to POSIX [[fs.norm.ref]]. How
 such behavior is actually implemented is unspecified.
 [*Note 1*: This constitutes an “as if” rule allowing implementations to
 call native operating system or other APIs. — *end note*]
+Implementations should provide such behavior as it is defined by POSIX.
+Implementations shall document any behavior that differs from the
+behavior defined by POSIX. Implementations that do not support exact
+POSIX behavior should provide behavior as close to POSIX behavior as is
+reasonable given the limitations of actual operating systems and file
+systems. If an implementation cannot provide any reasonable behavior,
+the implementation shall report an error as specified in
+[[fs.err.report]].
 [*Note 2*: This allows users to rely on an exception being thrown or an
 error code being set when an implementation cannot provide any
 reasonable behavior. — *end note*]
 required to support those features on the FAT file system but instead
 are required to report an error as described above. — *end example*]
 #### Operating system dependent behavior conformance <a id="fs.conform.os">[[fs.conform.os]]</a>
+Behavior that is specified as being *operating system dependent* is
+dependent upon the behavior and characteristics of an operating system.
+The operating system an implementation is dependent upon is
+*implementation-defined*.
 It is permissible for an implementation to be dependent upon an
 operating system emulator rather than the actual underlying operating
 system.
 #### File system race behavior <a id="fs.race.behavior">[[fs.race.behavior]]</a>
+A *file system race* is the condition that occurs when multiple threads,
+processes, or computers interleave access and modification of the same
+object within a file system. Behavior is undefined if calls to functions
+provided by subclause  [[fs.race.behavior]] introduce a file system
+race.
 If the possibility of a file system race would make it unreliable for a
 program to test for a precondition before calling a function described
+herein, *Preconditions:* is not specified for the function.
 [*Note 1*: As a design practice, preconditions are not specified when
 it is unreasonable for a program to detect them prior to calling the
 function. — *end note*]
 ### Normative references <a id="fs.norm.ref">[[fs.norm.ref]]</a>
+Subclause  [[filesystems]] mentions commercially available operating
+systems for purposes of exposition.[^41]
 ### Requirements <a id="fs.req">[[fs.req]]</a>
+Throughout subclause  [[filesystems]], `char`, `wchar_t`, `char8_t`,
+`char16_t`, and `char32_t` are collectively called *encoded character
+types*.
 Functions with template parameters named `EcharT` shall not participate
 in overload resolution unless `EcharT` is one of the encoded character
 types.
+Template parameters named `InputIterator` shall meet the
+*Cpp17InputIterator* requirements [[input.iterators]] and shall have a
+value type that is one of the encoded character types.
 [*Note 1*: Use of an encoded character type implies an associated
 character set and encoding. Since `signed char` and `unsigned char` have
 no implied character set and encoding, they are not included as
 permitted types. — *end note*]
+Template parameters named `Allocator` shall meet the *Cpp17Allocator*
+requirements ([[cpp17.allocator]]).
 #### Namespaces and headers <a id="fs.req.namespace">[[fs.req.namespace]]</a>
+Unless otherwise specified, references to entities described in
+subclause  [[filesystems]] are assumed to be qualified with
+`::std::filesystem::`.
 ### Header `<filesystem>` synopsis <a id="fs.filesystem.syn">[[fs.filesystem.syn]]</a>
 ``` cpp
+#include <compare>              // see [compare.syn]
 namespace std::filesystem {
   // [fs.class.path], paths
   class path;
   // [fs.path.nonmember], path non-member functions
   void swap(path& lhs, path& rhs) noexcept;
   size_t hash_value(const path& p) noexcept;
+ // [fs.class.filesystem.error], filesystem errors
   class filesystem_error;
+  // [fs.class.directory.entry], directory entries
   class directory_entry;
+  // [fs.class.directory.iterator], directory iterators
   class directory_iterator;
   // [fs.dir.itr.nonmembers], range access for directory iterators
   directory_iterator begin(directory_iterator iter) noexcept;
   directory_iterator end(const directory_iterator&) noexcept;
   // [fs.rec.dir.itr.nonmembers], range access for recursive directory iterators
   recursive_directory_iterator begin(recursive_directory_iterator iter) noexcept;
   recursive_directory_iterator end(const recursive_directory_iterator&) noexcept;
+  // [fs.class.file.status], file status
   class file_status;
   struct space_info {
     uintmax_t capacity;
     uintmax_t free;
     uintmax_t available;
+    friend bool operator==(const space_info&, const space_info&) = default;
   };
   // [fs.enum], enumerations
   enum class file_type;
   enum class perms;
   enum class perm_options;
   enum class copy_options;
   enum class directory_options;
+  using file_time_type = chrono::time_point<chrono::file_clock>;
   // [fs.op.funcs], filesystem operations
+  path absolute(const path& p);
+  path absolute(const path& p, error_code& ec);
+  path canonical(const path& p);
   path canonical(const path& p, error_code& ec);
   void copy(const path& from, const path& to);
+  void copy(const path& from, const path& to, error_code& ec);
   void copy(const path& from, const path& to, copy_options options);
   void copy(const path& from, const path& to, copy_options options,
+            error_code& ec);
   bool copy_file(const path& from, const path& to);
+  bool copy_file(const path& from, const path& to, error_code& ec);
   bool copy_file(const path& from, const path& to, copy_options option);
   bool copy_file(const path& from, const path& to, copy_options option,
+                 error_code& ec);
   void copy_symlink(const path& existing_symlink, const path& new_symlink);
   void copy_symlink(const path& existing_symlink, const path& new_symlink,
                     error_code& ec) noexcept;
   bool create_directories(const path& p);
+  bool create_directories(const path& p, error_code& ec);
   bool create_directory(const path& p);
   bool create_directory(const path& p, error_code& ec) noexcept;
   bool create_directory(const path& p, const path& attributes);
   path current_path();
   path current_path(error_code& ec);
   void current_path(const path& p);
   void current_path(const path& p, error_code& ec) noexcept;
+  bool equivalent(const path& p1, const path& p2);
+  bool equivalent(const path& p1, const path& p2, error_code& ec) noexcept;
   bool exists(file_status s) noexcept;
   bool exists(const path& p);
   bool exists(const path& p, error_code& ec) noexcept;
   uintmax_t file_size(const path& p);
   uintmax_t file_size(const path& p, error_code& ec) noexcept;
   uintmax_t hard_link_count(const path& p);
   uintmax_t hard_link_count(const path& p, error_code& ec) noexcept;
   bool is_directory(file_status s) noexcept;
   bool is_directory(const path& p);
   bool is_directory(const path& p, error_code& ec) noexcept;
   bool is_empty(const path& p);
+  bool is_empty(const path& p, error_code& ec);
   bool is_fifo(file_status s) noexcept;
   bool is_fifo(const path& p);
   bool is_fifo(const path& p, error_code& ec) noexcept;
   bool remove(const path& p);
   bool remove(const path& p, error_code& ec) noexcept;
   uintmax_t remove_all(const path& p);
+  uintmax_t remove_all(const path& p, error_code& ec);
   void rename(const path& from, const path& to);
   void rename(const path& from, const path& to, error_code& ec) noexcept;
   void resize_file(const path& p, uintmax_t size);
   path weakly_canonical(const path& p);
   path weakly_canonical(const path& p, error_code& ec);
 }
 ```
+Implementations should ensure that the resolution and range of
+`file_time_type` reflect the operating system dependent resolution and
+range of file time values.
 ### Error reporting <a id="fs.err.report">[[fs.err.report]]</a>
 Filesystem library functions often provide two overloads, one that
 throws an exception to report file system errors, and another that sets
   appropriate for the specific operating system dependent error.
   Otherwise, `clear()` is called on the `error_code&` argument.
 ### Class `path` <a id="fs.class.path">[[fs.class.path]]</a>
+An object of class `path` represents a path and contains a pathname.
+Such an object is concerned only with the lexical and syntactic aspects
+of a path. The path does not necessarily exist in external storage, and
+the pathname is not necessarily valid for the current operating system
+or for a particular file system.
 [*Note 1*: Class `path` is used to support the differences between the
 string types used by different operating systems to represent pathnames,
 and to perform conversions between encodings when
 necessary. — *end note*]
+A *path* is a sequence of elements that identify the location of a file
+within a filesystem. The elements are the *root-name*ₒₚₜ ,
+*root-directory*ₒₚₜ , and an optional sequence of *filename*s
+[[fs.path.generic]]. The maximum number of elements in the sequence is
+operating system dependent [[fs.conform.os]].
+An *absolute path* is a path that unambiguously identifies the location
+of a file without reference to an additional starting location. The
+elements of a path that determine if it is absolute are operating system
+dependent. A *relative path* is a path that is not absolute, and as
+such, only unambiguously identifies the location of a file when resolved
+relative to an implied starting location. The elements of a path that
+determine if it is relative are operating system dependent.
+[*Note 2*: Pathnames “.” and “..” are relative paths. — *end note*]
+A *pathname* is a character string that represents the name of a path.
+Pathnames are formatted according to the generic pathname format grammar
+[[fs.path.generic]] or according to an operating system dependent
+*native pathname format* accepted by the host operating system.
+*Pathname resolution* is the operating system dependent mechanism for
+resolving a pathname to a particular file in a file hierarchy. There may
+be multiple pathnames that resolve to the same file.
+[*Example 1*: POSIX specifies the mechanism in section 4.11, Pathname
+resolution. — *end example*]
 ``` cpp
 namespace std::filesystem {
   class path {
   public:
     using value_type  = see below;
     path& operator=(string_type&& source);
     path& assign(string_type&& source);
     template<class Source>
       path& operator=(const Source& source);
     template<class Source>
+      path& assign(const Source& source);
     template<class InputIterator>
       path& assign(InputIterator first, InputIterator last);
     // [fs.path.append], appends
     path& operator/=(const path& p);
     path& remove_filename();
     path& replace_filename(const path& replacement);
     path& replace_extension(const path& replacement = path());
     void  swap(path& rhs) noexcept;
+    // [fs.path.nonmember], non-member operators
+    friend bool operator==(const path& lhs, const path& rhs) noexcept;
+    friend strong_ordering operator<=>(const path& lhs, const path& rhs) noexcept;
+    friend path operator/ (const path& lhs, const path& rhs);
     // [fs.path.native.obs], native format observers
     const string_type& native() const noexcept;
     const value_type*  c_str() const noexcept;
     operator string_type() const;
              class Allocator = allocator<EcharT>>
       basic_string<EcharT, traits, Allocator>
         string(const Allocator& a = Allocator()) const;
     std::string    string() const;
     std::wstring   wstring() const;
+    std::u8string  u8string() const;
     std::u16string u16string() const;
     std::u32string u32string() const;
     // [fs.path.generic.obs], generic format observers
     template<class EcharT, class traits = char_traits<EcharT>,
              class Allocator = allocator<EcharT>>
       basic_string<EcharT, traits, Allocator>
         generic_string(const Allocator& a = Allocator()) const;
     std::string    generic_string() const;
     std::wstring   generic_wstring() const;
+    std::u8string  generic_u8string() const;
     std::u16string generic_u16string() const;
     std::u32string generic_u32string() const;
     // [fs.path.compare], compare
     int compare(const path& p) const noexcept;
     path filename() const;
     path stem() const;
     path extension() const;
     // [fs.path.query], query
+ [[nodiscard]] bool empty() const noexcept;
     bool has_root_name() const;
     bool has_root_directory() const;
     bool has_root_path() const;
     bool has_relative_path() const;
     bool has_parent_path() const;
     class iterator;
     using const_iterator = iterator;
     iterator begin() const;
     iterator end() const;
+    // [fs.path.io], path inserter and extractor
+    template<class charT, class traits>
+      friend basic_ostream<charT, traits>&
+        operator<<(basic_ostream<charT, traits>& os, const path& p);
+    template<class charT, class traits>
+      friend basic_istream<charT, traits>&
+        operator>>(basic_istream<charT, traits>& is, path& p);
   };
 }
 ```
 `value_type` is a `typedef` for the operating system dependent encoded
 character type used to represent pathnames.
 The value of the `preferred_separator` member is the operating system
+dependent *preferred-separator* character [[fs.path.generic]].
+[*Example 2*: For POSIX-based operating systems, `value_type` is `char`
 and `preferred_separator` is the slash character (`'/'`). For
 Windows-based operating systems, `value_type` is `wchar_t` and
 `preferred_separator` is the backslash character
 (`L'\\'`). — *end example*]
 ``` bnf
 fallback-separator:
     /, if *preferred-separator* is not /
 ```
+A *filename* is the name of a file. The *dot* and *dot-dot* filenames,
+consisting solely of one and two period characters respectively, have
+special meaning. The following characteristics of filenames are
+operating system dependent:
+- The permitted characters. \[*Example 1*: Some operating systems
+  prohibit the ASCII control characters (0x00 – 0x1F) in
+  filenames. — *end example*] \[*Note 1*: For wide portability, users
+  may wish to limit *filename* characters to the POSIX Portable Filename
+  Character Set:
   `A B C D E F G H I J K L M N O P Q R S T U V W X Y Z`
   `a b c d e f g h i j k l m n o p q r s t u v w x y z`
   `0 1 2 3 4 5 6 7 8 9 . _ -` — *end note*]
+- The maximum permitted length.
+- Filenames that are not permitted.
+- Filenames that have special meaning.
+- Case awareness and sensitivity during path resolution.
+- Special rules that may apply to file types other than regular files,
+  such as directories.
 Except in a *root-name*, multiple successive *directory-separator*
 characters are considered to be the same as one *directory-separator*
 character.
+The dot filename is treated as a reference to the current directory. The
+dot-dot filename is treated as a reference to the parent directory. What
+the dot-dot filename refers to relative to *root-directory* is
 *implementation-defined*. Specific filenames may have special meanings
 for a particular operating system.
+A *root-name* identifies the starting location for pathname resolution
+[[fs.class.path]]. If there are no operating system dependent
 *root-name*s, at least one *implementation-defined* *root-name* is
 required.
 [*Note 2*: Many operating systems define a name beginning with two
 *directory-separator* characters as a *root-name* that identifies
 [*Note 3*: On a POSIX-like operating system, it is impossible to have a
 *root-name* and a *relative-path* without an intervening
 *root-directory* element. — *end note*]
+*Normalization* of a generic format pathname means:
+1.  If the path is empty, stop.
+2.  Replace each slash character in the *root-name* with a
+    *preferred-separator*.
+3.  Replace each *directory-separator* with a *preferred-separator*.
+    \[*Note 4*: The generic pathname grammar [[fs.path.generic]] defines
+    *directory-separator* as one or more slashes and
+    *preferred-separator*s. — *end note*]
+4.  Remove each dot filename and any immediately following
+    *directory-separator*.
+5.  As long as any appear, remove a non-dot-dot filename immediately
+    followed by a *directory-separator* and a dot-dot filename, along
+    with any immediately following *directory-separator*.
+6.  If there is a *root-directory*, remove all dot-dot filenames and any
+    *directory-separator*s immediately following them. \[*Note 5*: These
+    dot-dot filenames attempt to refer to nonexistent parent
+    directories. — *end note*]
+7.  If the last filename is dot-dot, remove any trailing
+    *directory-separator*.
+8.  If the path is empty, add a dot.
+The result of normalization is a path in *normal form*, which is said to
+be *normalized*.
+#### Conversions <a id="fs.path.cvt">[[fs.path.cvt]]</a>
+##### Argument format conversions <a id="fs.path.fmt.cvt">[[fs.path.fmt.cvt]]</a>
 [*Note 1*:
+The format conversions described in this subclause are not applied on
 POSIX-based operating systems because on these systems:
 - The generic format is acceptable as a native path.
 - There is no need to distinguish between native format and generic
   format in function arguments.
 — *end note*]
 Several functions are defined to accept *detected-format* arguments,
 which are character sequences. A detected-format argument represents a
+path using either a pathname in the generic format [[fs.path.generic]]
+or a pathname in the native format [[fs.class.path]]. Such an argument
+is taken to be in the generic format if and only if it matches the
+generic format and is not acceptable to the operating system as a native
+path.
 [*Note 2*: Some operating systems may have no unambiguous way to
 distinguish between native format and generic format arguments. This is
 by design as it simplifies use for operating systems that do not require
 disambiguation. An implementation for an operating system where
 If the native format requires paths for regular files to be formatted
 differently from paths for directories, the path shall be treated as a
 directory path if its last element is a *directory-separator*, otherwise
 it shall be treated as a path to a regular file.
+[*Note 4*: A path stores a native format pathname
+[[fs.path.native.obs]] and acts as if it also stores a generic format
 pathname, related as given below. The implementation may generate the
 generic format pathname based on the native format pathname (and
 possibly other information) when requested. — *end note*]
 When a path is constructed from or is assigned a single representation
 as appropriate) if any such value does so; *q* is otherwise unspecified.
 [*Note 5*: If *q* is the result of converting any path at all, it is
 the result of converting *p*. — *end note*]
+##### Type and encoding conversions <a id="fs.path.type.cvt">[[fs.path.type.cvt]]</a>
+The *native encoding* of an ordinary character string is the operating
+system dependent current encoding for pathnames [[fs.class.path]]. The
+*native encoding* for wide character strings is the
+implementation-defined execution wide-character set encoding
+[[lex.charset]].
 For member function arguments that take character sequences representing
 paths and for member functions returning strings, value type and
 encoding conversion is performed if the value type of the argument or
 return value differs from `path::value_type`. For the argument or return
 value, the method of conversion and the encoding to be converted to is
 determined by its value type:
+- `char`: The encoding is the native ordinary encoding. The method of
+  conversion, if any, is operating system dependent. \[*Note 6*: For
+ POSIX-based operating systems `path::value_type` is `char` so no
+ conversion from `char` value type arguments or to `char` value type
+ return values is performed. For Windows-based operating systems, the
+ native ordinary encoding is determined by calling a Windows API
   function. — *end note*] \[*Note 7*: This results in behavior
   identical to other C and C++ standard library functions that perform
+  file operations using ordinary character strings to identify paths.
   Changing this behavior would be surprising and error
   prone. — *end note*]
+- `wchar_t`: The encoding is the native wide encoding. The method of
+  conversion is unspecified. \[*Note 8*: For Windows-based operating
+  systems `path::value_type` is `wchar_t` so no conversion from
+  `wchar_t` value type arguments or to `wchar_t` value type return
+  values is performed. — *end note*]
+- `char8_t`: The encoding is UTF-8. The method of conversion is
+  unspecified.
 - `char16_t`: The encoding is UTF-16. The method of conversion is
   unspecified.
 - `char32_t`: The encoding is UTF-32. The method of conversion is
   unspecified.
 If the encoding being converted to has no representation for source
 characters, the resulting converted characters, if any, are unspecified.
 Implementations should not modify member function arguments if already
 of type `path::value_type`.
+#### Requirements <a id="fs.path.req">[[fs.path.req]]</a>
+In addition to the requirements [[fs.req]], function template parameters
+named `Source` shall be one of:
 - `basic_string<EcharT, traits, Allocator>`. A function argument
   `const Source&` `source` shall have an effective range
   \[`source.begin()`, `source.end()`).
 - `basic_string_view<EcharT, traits>`. A function argument
   `const Source&` `source` shall have an effective range
   \[`source.begin()`, `source.end()`).
+- A type meeting the *Cpp17InputIterator* requirements that iterates
+ over a NTCTS. The value type shall be an encoded character type. A
+ function argument `const Source&` `source` shall have an effective
+ range \[`source`, `end`) where `end` is the first iterator value with
+ an element value equal to `iterator_traits<Source>::value_type()`.
 - A character array that after array-to-pointer decay results in a
   pointer to the start of a NTCTS. The value type shall be an encoded
   character type. A function argument `const Source&` `source` shall
   have an effective range \[`source`, `end`) where `end` is the first
   iterator value with an element value equal to
   `iterator_traits<decay_t<Source>>::value_type()`.
 Functions taking template parameters named `Source` shall not
+participate in overload resolution unless `Source` denotes a type other
+than `path`, and either
 - `Source` is a specialization of `basic_string` or `basic_string_view`,
   or
 - the *qualified-id* `iterator_traits<decay_t<Source>>::value_type` is
+  valid and denotes a possibly `const` encoded character type
+  [[temp.deduct]].
+[*Note 1*: See path conversions [[fs.path.cvt]] for how the value types
+above and their encodings convert to `path::value_type` and its
 encoding. — *end note*]
 Arguments of type `Source` shall not be null pointers.
+#### Members <a id="fs.path.member">[[fs.path.member]]</a>
+##### Constructors <a id="fs.path.construct">[[fs.path.construct]]</a>
 ``` cpp
 path() noexcept;
 ```
+*Ensures:* `empty() == true`.
 ``` cpp
 path(const path& p);
 path(path&& p) noexcept;
 ```
 ``` cpp
 path(string_type&& source, format fmt = auto_format);
 ```
 *Effects:* Constructs an object of class `path` for which the pathname
+in the detected-format of `source` has the original value of `source`
+[[fs.path.fmt.cvt]], converting format if required [[fs.path.fmt.cvt]].
+`source` is left in a valid but unspecified state.
 ``` cpp
 template<class Source>
   path(const Source& source, format fmt = auto_format);
 template<class InputIterator>
   path(InputIterator first, InputIterator last, format fmt = auto_format);
 ```
+*Effects:* Let `s` be the effective range of `source` [[fs.path.req]] or
+the range \[`first`, `last`), with the encoding converted if
+required [[fs.path.cvt]]. Finds the detected-format of `s`
+[[fs.path.fmt.cvt]] and constructs an object of class `path` for which
+the pathname in that format is `s`.
 ``` cpp
 template<class Source>
   path(const Source& source, const locale& loc, format fmt = auto_format);
 template<class InputIterator>
   path(InputIterator first, InputIterator last, const locale& loc, format fmt = auto_format);
 ```
+*Mandates:* The value type of `Source` and `InputIterator` is `char`.
 *Effects:* Let `s` be the effective range of `source` or the range
 \[`first`, `last`), after converting the encoding as follows:
 - If `value_type` is `wchar_t`, converts to the native wide
+  encoding [[fs.path.type.cvt]] using the
   `codecvt<wchar_t, char, mbstate_t>` facet of `loc`.
 - Otherwise a conversion is performed using the
   `codecvt<wchar_t, char, mbstate_t>` facet of `loc`, and then a second
+  conversion to the current ordinary encoding.
+Finds the detected-format of `s` [[fs.path.fmt.cvt]] and constructs an
+object of class `path` for which the pathname in that format is `s`.
 [*Example 1*:
 A string is to be read from a database that is encoded in ISO/IEC
 8859-1, and used to create a directory:
 ```
 For POSIX-based operating systems, the path is constructed by first
 using `latin1_facet` to convert ISO/IEC 8859-1 encoded `latin1_string`
 to a wide character string in the native wide
+encoding [[fs.path.type.cvt]]. The resulting wide string is then
+converted to an ordinary character pathname string in the current native
+ordinary encoding. If the native wide encoding is UTF-16 or UTF-32, and
+the current native ordinary encoding is UTF-8, all of the characters in
 the ISO/IEC 8859-1 character set will be converted to their Unicode
+representation, but for other native ordinary encodings some characters
 may have no representation.
 For Windows-based operating systems, the path is constructed by using
 `latin1_facet` to convert ISO/IEC 8859-1 encoded `latin1_string` to a
 UTF-16 encoded wide character pathname string. All of the characters in
 the ISO/IEC 8859-1 character set will be converted to their Unicode
 representation.
 — *end example*]
+##### Assignments <a id="fs.path.assign">[[fs.path.assign]]</a>
 ``` cpp
 path& operator=(const path& p);
 ```
   path& assign(const Source& source);
 template<class InputIterator>
   path& assign(InputIterator first, InputIterator last);
 ```
+*Effects:* Let `s` be the effective range of `source` [[fs.path.req]] or
+the range \[`first`, `last`), with the encoding converted if
+required [[fs.path.cvt]]. Finds the detected-format of `s`
+[[fs.path.fmt.cvt]] and sets the pathname in that format to `s`.
 *Returns:* `*this`.
+##### Appends <a id="fs.path.append">[[fs.path.append]]</a>
 The append operations use `operator/=` to denote their semantic effect
 of appending *preferred-separator* when needed.
 ``` cpp
   pathname.
 [*Example 2*:
 Even if `//host` is interpreted as a *root-name*, both of the paths
+`path("//host")/"foo"` and `path("//host/")/"foo"` equal `"//host/foo"`
+(although the former might use backslash as the preferred separator).
 Expression examples:
 ``` cpp
 // On POSIX,
+path("foo") /= path(""); // yields path("foo/")
+path("foo") /= path("/bar"); // yields path("/bar")
 // On Windows,
+path("foo") /= path(""); // yields path("foo\{")}
+path("foo") /= path("/bar"); // yields path("/bar")
+path("foo") /= path("c:/bar"); // yields path("c:/bar")
+path("foo") /= path("c:"); // yields path("c:")
+path("c:") /= path(""); // yields path("c:")
+path("c:foo") /= path("/bar");  // yields path("c:/bar")
+path("c:foo") /= path("c:bar"); // yields path("c:foo\{bar")}
 ```
 — *end example*]
 *Returns:* `*this`.
   path& append(InputIterator first, InputIterator last);
 ```
 *Effects:* Equivalent to: `return operator/=(path(first, last));`
+##### Concatenation <a id="fs.path.concat">[[fs.path.concat]]</a>
 ``` cpp
 path& operator+=(const path& x);
 path& operator+=(const string_type& x);
 path& operator+=(basic_string_view<value_type> x);
 path& operator+=(const value_type* x);
 template<class Source>
   path& operator+=(const Source& x);
 template<class Source>
   path& concat(const Source& x);
 ```
 *Effects:* Appends `path(x).native()` to the pathname in the native
 [*Note 2*: This directly manipulates the value of `native()` and may
 not be portable between operating systems. — *end note*]
 *Returns:* `*this`.
+``` cpp
+path& operator+=(value_type x);
+template<class EcharT>
+  path& operator+=(EcharT x);
+```
+*Effects:* Equivalent to: `return *this += basic_string_view(&x, 1);`
 ``` cpp
 template<class InputIterator>
   path& concat(InputIterator first, InputIterator last);
 ```
+*Effects:* Equivalent to: `return *this += path(first, last);`
+##### Modifiers <a id="fs.path.modifiers">[[fs.path.modifiers]]</a>
 ``` cpp
 void clear() noexcept;
 ```
+*Ensures:* `empty() == true`.
 ``` cpp
 path& make_preferred();
 ```
 ``` cpp
 path& remove_filename();
 ```
 *Effects:* Remove the generic format pathname of `filename()` from the
 generic format pathname.
+*Ensures:* `!has_filename()`.
 *Returns:* `*this`.
 [*Example 4*:
 ``` cpp
 path& replace_extension(const path& replacement = path());
 ```
 *Effects:*
+- Any existing `extension()` [[fs.path.decompose]] is removed from the
+  pathname in the generic format, then
 - If `replacement` is not empty and does not begin with a dot character,
   a dot character is appended to the pathname in the generic format,
   then
 - `operator+=(replacement);`.
 *Effects:* Swaps the contents (in all formats) of the two paths.
 *Complexity:* Constant time.
+##### Native format observers <a id="fs.path.native.obs">[[fs.path.native.obs]]</a>
 The string returned by all native format observers is in the native
+pathname format [[fs.class.path]].
 ``` cpp
 const string_type& native() const noexcept;
 ```
 ``` cpp
 const value_type* c_str() const noexcept;
 ```
+*Effects:* Equivalent to: `return native().c_str();`
 ``` cpp
 operator string_type() const;
 ```
 [[fs.path.cvt]].
 ``` cpp
 std::string string() const;
 std::wstring wstring() const;
+std::u8string u8string() const;
 std::u16string u16string() const;
 std::u32string u32string() const;
 ```
+*Returns:* `native()`.
 *Remarks:* Conversion, if any, is performed as specified by
+[[fs.path.cvt]].
+##### Generic format observers <a id="fs.path.generic.obs">[[fs.path.generic.obs]]</a>
 Generic format observer functions return strings formatted according to
+the generic pathname format [[fs.path.generic]]. A single slash (`'/'`)
+character is used as the *directory-separator*.
 [*Example 1*:
 On an operating system that uses backslash as its *preferred-separator*,
 [[fs.path.cvt]].
 ``` cpp
 std::string generic_string() const;
 std::wstring generic_wstring() const;
+std::u8string generic_u8string() const;
 std::u16string generic_u16string() const;
 std::u32string generic_u32string() const;
 ```
 *Returns:* The pathname in the generic format.
+*Remarks:* Conversion, if any, is specified by  [[fs.path.cvt]].
+##### Compare <a id="fs.path.compare">[[fs.path.compare]]</a>
 ``` cpp
 int compare(const path& p) const noexcept;
 ```
 *Returns:*
+- Let `rootNameComparison` be the result of
+  `this->root_name().native().compare(p.root_name().native())`. If
+ `rootNameComparison` is not `0`, `rootNameComparison`.
+- Otherwise, if `!this->has_root_directory()` and
+  `p.has_root_directory()`, a value less than `0`.
+- Otherwise, if `this->has_root_directory()` and
+  `!p.has_root_directory()`, a value greater than `0`.
+- Otherwise, if `native()` for the elements of `this->relative_path()`
+ are lexicographically less than `native()` for the elements of
+ `p.relative_path()`, a value less than `0`.
+- Otherwise, if `native()` for the elements of `this->relative_path()`
+  are lexicographically greater than `native()` for the elements of
+  `p.relative_path()`, a value greater than `0`.
+- Otherwise, `0`.
 ``` cpp
+int compare(const string_type& s) const;
 int compare(basic_string_view<value_type> s) const;
+int compare(const value_type* s) const;
 ```
+*Effects:* Equivalent to: `return compare(path(s));`
+##### Decomposition <a id="fs.path.decompose">[[fs.path.decompose]]</a>
 ``` cpp
 path root_name() const;
 ```
 ``` cpp
 path relative_path() const;
 ```
 *Returns:* A `path` composed from the pathname in the generic format, if
+`empty()` is `false`, beginning with the first *filename* after
+`root_path()`. Otherwise, `path()`.
 ``` cpp
 path parent_path() const;
 ```
+*Returns:* `*this` if `has_relative_path()` is `false`, otherwise a path
+whose generic format pathname is the longest prefix of the generic
+format pathname of `*this` that produces one fewer element in its
+iteration.
 ``` cpp
 path filename() const;
 ```
 ``` cpp
 path extension() const;
 ```
+*Returns:* A path whose pathname in the generic format is the suffix of
 `filename()` not included in `stem()`.
 [*Example 8*:
 ``` cpp
 [*Note 5*: On non-POSIX operating systems, for a path `p`, it may not
 be the case that `p.stem() + p.extension() == p.filename()`, even though
 the generic format pathnames are the same. — *end note*]
+##### Query <a id="fs.path.query">[[fs.path.query]]</a>
 ``` cpp
+[[nodiscard]] bool empty() const noexcept;
 ```
+*Returns:* `true` if the pathname in the generic format is empty,
+otherwise `false`.
 ``` cpp
 bool has_root_path() const;
 ```
 ``` cpp
 bool is_absolute() const;
 ```
 *Returns:* `true` if the pathname in the native format contains an
+absolute path [[fs.class.path]], otherwise `false`.
 [*Example 9*: `path("/").is_absolute()` is `true` for POSIX-based
 operating systems, and `false` for Windows-based operating
 systems. — *end example*]
 bool is_relative() const;
 ```
 *Returns:* `!is_absolute()`.
+##### Generation <a id="fs.path.gen">[[fs.path.gen]]</a>
 ``` cpp
 path lexically_normal() const;
 ```
 *Returns:* A path whose pathname in the generic format is the normal
+form [[fs.path.generic]] of the pathname in the generic format of
 `*this`.
 [*Example 10*:
 ``` cpp
 ``` cpp
 path lexically_relative(const path& base) const;
 ```
 *Returns:* `*this` made relative to `base`. Does not
+resolve [[fs.class.path]] symlinks. Does not first
+normalize [[fs.path.generic]] `*this` or `base`.
+*Effects:* If:
+- `root_name() != base.root_name()` is `true`, or
+- `is_absolute() != base.is_absolute()` is `true`, or
+- `!has_root_directory() && base.has_root_directory()` is `true`, or
+- any *filename* in `relative_path()` or `base.relative_path()` can be
+  interpreted as a *root-name*,
+returns `path()`.
+[*Note 6*: On a POSIX implementation, no *filename* in a
+*relative-path* is acceptable as a *root-name*. — *end note*]
+Determines the first mismatched element of `*this` and `base` as if by:
 ``` cpp
 auto [a, b] = mismatch(begin(), end(), base.begin(), base.end());
 ```
 Then,
 - if `a == end()` and `b == base.end()`, returns `path(".")`; otherwise
 - let `n` be the number of *filename* elements in \[`b`, `base.end()`)
+  that are not dot or dot-dot or empty, minus the number that are
+ dot-dot. If `n<0,` returns `path()`; otherwise
+- if `n == 0` and `(a == end() || a->empty())`, returns `path(".")`;
+  otherwise
 - returns an object of class `path` that is default-constructed,
   followed by
   - application of `operator/=(path(".."))` `n` times, and then
   - application of `operator/=` for each element in \[`a`, `end()`).
 *directory-separator* characters will be backslashes rather than
 slashes, but that does not affect `path` equality.
 — *end example*]
+[*Note 7*: If symlink following semantics are desired, use the
 operational function `relative()`. — *end note*]
+[*Note 8*: If normalization [[fs.path.generic]] is needed to ensure
+consistent matching of elements, apply `lexically_normal()` to `*this`,
+`base`, or both. — *end note*]
 ``` cpp
 path lexically_proximate(const path& base) const;
 ```
 *Returns:* If the value of `lexically_relative(base)` is not an empty
 path, return it. Otherwise return `*this`.
+[*Note 9*: If symlink following semantics are desired, use the
 operational function `proximate()`. — *end note*]
+[*Note 10*: If normalization [[fs.path.generic]] is needed to ensure
+consistent matching of elements, apply `lexically_normal()` to `*this`,
+`base`, or both. — *end note*]
+#### Iterators <a id="fs.path.itr">[[fs.path.itr]]</a>
 Path iterators iterate over the elements of the pathname in the generic
+format [[fs.path.generic]].
+A `path::iterator` is a constant iterator meeting all the requirements
+of a bidirectional iterator [[bidirectional.iterators]] except that, for
+dereferenceable iterators `a` and `b` of type `path::iterator` with
+`a == b`, there is no requirement that `*a` and `*b` are bound to the
+same object. Its `value_type` is `path`.
 Calling any non-const member function of a `path` object invalidates all
 iterators referring to elements of that object.
 For the elements of the pathname in the generic format, the forward
 iterator end() const;
 ```
 *Returns:* The end iterator.
+#### Inserter and extractor <a id="fs.path.io">[[fs.path.io]]</a>
+``` cpp
+template<class charT, class traits>
+  friend basic_ostream<charT, traits>&
+    operator<<(basic_ostream<charT, traits>& os, const path& p);
+```
+*Effects:* Equivalent to `os << quoted(p.string<charT, traits>())`.
+[*Note 1*: The `quoted` function is described
+in  [[quoted.manip]]. — *end note*]
+*Returns:* `os`.
+``` cpp
+template<class charT, class traits>
+  friend basic_istream<charT, traits>&
+    operator>>(basic_istream<charT, traits>& is, path& p);
+```
+*Effects:* Equivalent to:
+``` cpp
+basic_string<charT, traits> tmp;
+is >> quoted(tmp);
+p = tmp;
+```
+*Returns:* `is`.
+#### Non-member functions <a id="fs.path.nonmember">[[fs.path.nonmember]]</a>
 ``` cpp
 void swap(path& lhs, path& rhs) noexcept;
 ```
+*Effects:* Equivalent to `lhs.swap(rhs)`.
 ``` cpp
 size_t hash_value (const path& p) noexcept;
 ```
 *Returns:* A hash value for the path `p`. If for two paths, `p1 == p2`
 then `hash_value(p1) == hash_value(p2)`.
 ``` cpp
+friend bool operator==(const path& lhs, const path& rhs) noexcept;
 ```
+*Returns:* `lhs.compare(rhs) == 0`.
 [*Note 1*:
 Path equality and path equivalence have different semantics.
 - Equality is determined by the `path` non-member `operator==`, which
+  considers the two paths’ lexical representations only.
   \[*Example 1*: `path("foo") == "bar"` is never
   `true`. — *end example*]
 - Equivalence is determined by the `equivalent()` non-member function,
+  which determines if two paths resolve [[fs.class.path]] to the same
+  file system entity. \[*Example 2*: `equivalent("foo", "bar")` will be
+  `true` when both paths resolve to the same file. — *end example*]
 Programmers wishing to determine if two paths are “the same” must decide
 if “the same” means “the same representation” or “resolve to the same
 actual file”, and choose the appropriate function accordingly.
 — *end note*]
 ``` cpp
+friend strong_ordering operator<=>(const path& lhs, const path& rhs) noexcept;
 ```
+*Returns:* `lhs.compare(rhs) <=> 0`.
 ``` cpp
+friend path operator/ (const path& lhs, const path& rhs);
 ```
 *Effects:* Equivalent to: `return path(lhs) /= rhs;`
+### Class `filesystem_error` <a id="fs.class.filesystem.error">[[fs.class.filesystem.error]]</a>
 ``` cpp
 namespace std::filesystem {
   class filesystem_error : public system_error {
   public:
   };
 }
 ```
 The class `filesystem_error` defines the type of objects thrown as
+exceptions to report file system errors from functions described in
+subclause  [[filesystems]].
+#### Members <a id="fs.filesystem.error.members">[[fs.filesystem.error.members]]</a>
 Constructors are provided that store zero, one, or two paths associated
 with an error.
 ``` cpp
 filesystem_error(const string& what_arg, error_code ec);
 ```
+*Ensures:*
+- `code() == ec`,
+- `path1().empty() == true`,
+- `path2().empty() == true`, and
+- `string_view(what()).find(what_arg.c_str())` `!= string_view::npos`.
 ``` cpp
 filesystem_error(const string& what_arg, const path& p1, error_code ec);
 ```
+*Ensures:*
+- `code() == ec`,
+- `path1()` returns a reference to the stored copy of `p1`,
+- `path2().empty() == true`, and
+- `string_view(what()).find(what_arg.c_str())` `!= string_view::npos`.
 ``` cpp
 filesystem_error(const string& what_arg, const path& p1, const path& p2, error_code ec);
 ```
+*Ensures:*
+- `code() == ec`,
+- `path1()` returns a reference to the stored copy of `p1`,
+- `path2()` returns a reference to the stored copy of `p2`, and
+- `string_view(what()).find(what_arg.c_str())` `!= string_view::npos`.
 ``` cpp
 const path& path1() const noexcept;
 ```
 ``` cpp
 const char* what() const noexcept override;
 ```
+*Returns:* An NTBS that incorporates the `what_arg` argument supplied to
+the constructor. The exact format is unspecified. Implementations should
+include the `system_error::what()` string and the pathnames of `path1`
+and `path2` in the native format in the returned string.
 ### Enumerations <a id="fs.enum">[[fs.enum]]</a>
 #### Enum `path::format` <a id="fs.enum.path.format">[[fs.enum.path.format]]</a>
 This enum specifies constants used to identify the format of the
+character sequence, with the meanings listed in [[fs.enum.path.format]].
 [*Note 1*: For POSIX-based systems, native and generic formats are
 equivalent and the character sequence should always be interpreted in
 the same way. — *end note*]
+#### Enum class `file_type` <a id="fs.enum.file.type">[[fs.enum.file.type]]</a>
 This enum class specifies constants used to identify file types, with
+the meanings listed in [[fs.enum.file.type]]. The values of the
+constants are distinct.
 [*Note 1*: The file not being found is not considered an error while
 determining the type of a file. — *end note*]
 #### Enum class `copy_options` <a id="fs.enum.copy.opts">[[fs.enum.copy.opts]]</a>
+The `enum class` type `copy_options` is a bitmask type [[bitmask.types]]
+that specifies bitmask constants used to control the semantics of copy
+operations. The constants are specified in option groups with the
+meanings listed in [[fs.enum.copy.opts]]. The constant `none` represents
+the empty bitmask, and is shown in each option group for purposes of
 exposition; implementations shall provide only a single definition.
+Every other constant in the table represents a distinct bitmask element.
+**Table: Enum class `copy_options`** <a id="fs.enum.copy.opts">[fs.enum.copy.opts]</a>
 | Constant             | Meaning                                                                                                                                               |
 | -------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- |
 | `none`               | (Default) Error; file already exists.                                                                                                                 |
 | `skip_existing`      | Do not overwrite existing file, do not report an error.                                                                                               |
 | `create_hard_links`  | Make hard links instead of copies of files.                                                                                                           |
 #### Enum class `perms` <a id="fs.enum.perms">[[fs.enum.perms]]</a>
+The `enum class` type `perms` is a bitmask type [[bitmask.types]] that
+specifies bitmask constants used to identify file permissions, with the
+meanings listed in [[fs.enum.perms]].
+**Table: Enum class `perms`** <a id="fs.enum.perms">[fs.enum.perms]</a>
 | Name           | Value (octal) | POSIX macro | Definition or notes                                                                                              |
 | -------------- | ------------- | ----------- | ---------------------------------------------------------------------------------------------------------------- |
 | `none`         | `0`           |             | There are no permissions set for the file.                                                                       |
 | `owner_read`   | `0400`        | `S_IRUSR`   | Read permission, owner                                                                                           |
 | `unknown`      | `0xFFFF`      |             | The permissions are not known, such as when a `file_status` object is created without specifying the permissions |
 #### Enum class `perm_options` <a id="fs.enum.perm.opts">[[fs.enum.perm.opts]]</a>
+The `enum class` type `perm_options` is a bitmask type [[bitmask.types]]
+that specifies bitmask constants used to control the semantics of
+permissions operations, with the meanings listed in
+[[fs.enum.perm.opts]]. The bitmask constants are bitmask elements. In
+[[fs.enum.perm.opts]] `perm` denotes a value of type `perms` passed to
+`permissions`.
+**Table: Enum class `perm_options`** <a id="fs.enum.perm.opts">[fs.enum.perm.opts]</a>
 | Name       | Meaning                                                                                                                                                 |
+| ---------- | ------------------------------------------------------------------------------------------------------------------------------------------------------- |
 | `replace`  | `permissions` shall replace the file's permission bits with `perm`                                                                                      |
+| `add`      | `permissions` shall replace the file's permission bits with the bitwise \logop{OR} of `perm` and the file's current permission bits.                    |
+| `remove`   | `permissions` shall replace the file's permission bits with the bitwise \logop{AND} of the complement of `perm` and the file's current permission bits. |
 | `nofollow` | `permissions` shall change the permissions of a symbolic link itself rather than the permissions of the file the link resolves to.                      |
 #### Enum class `directory_options` <a id="fs.enum.dir.opts">[[fs.enum.dir.opts]]</a>
+The `enum class` type `directory_options` is a bitmask type
+[[bitmask.types]] that specifies bitmask constants used to identify
+directory traversal options, with the meanings listed in
+[[fs.enum.dir.opts]]. The constant `none` represents the empty bitmask;
+every other constant in the table represents a distinct bitmask element.
+**Table: Enum class `directory_options`** <a id="fs.enum.dir.opts">[fs.enum.dir.opts]</a>
 | Name                       | Meaning                                                            |
 | -------------------------- | ------------------------------------------------------------------ |
 | `none`                     | (Default) Skip directory symlinks, permission denied is an error.  |
 | `follow_directory_symlink` | Follow rather than skip directory symlinks.                        |
 | `skip_permission_denied`   | Skip directories that would otherwise result in permission denied. |
+### Class `file_status` <a id="fs.class.file.status">[[fs.class.file.status]]</a>
 ``` cpp
 namespace std::filesystem {
   class file_status {
   public:
+    // [fs.file.status.cons], constructors and destructor
     file_status() noexcept : file_status(file_type::none) {}
     explicit file_status(file_type ft,
                          perms prms = perms::unknown) noexcept;
     file_status(const file_status&) noexcept = default;
     file_status(file_status&&) noexcept = default;
     ~file_status();
+    // assignments
     file_status& operator=(const file_status&) noexcept = default;
     file_status& operator=(file_status&&) noexcept = default;
+    // [fs.file.status.mods], modifiers
     void       type(file_type ft) noexcept;
     void       permissions(perms prms) noexcept;
+    // [fs.file.status.obs], observers
     file_type  type() const noexcept;
     perms      permissions() const noexcept;
+    friend bool operator==(const file_status& lhs, const file_status& rhs) noexcept
+      { return lhs.type() == rhs.type() && lhs.permissions() == rhs.permissions(); }
   };
 }
 ```
+#### Constructors <a id="fs.file.status.cons">[[fs.file.status.cons]]</a>
 ``` cpp
 explicit file_status(file_type ft, perms prms = perms::unknown) noexcept;
 ```
+*Ensures:* `type() == ft` and `permissions() == prms`.
+#### Observers <a id="fs.file.status.obs">[[fs.file.status.obs]]</a>
 ``` cpp
 file_type type() const noexcept;
 ```
 *Returns:* The value of `permissions()` specified by the postconditions
 of the most recent call to a constructor, `operator=`, or
 `permissions(perms)` function.
+#### Modifiers <a id="fs.file.status.mods">[[fs.file.status.mods]]</a>
 ``` cpp
 void type(file_type ft) noexcept;
 ```
+*Ensures:* `type() == ft`.
 ``` cpp
 void permissions(perms prms) noexcept;
 ```
+*Ensures:* `permissions() == prms`.
+### Class `directory_entry` <a id="fs.class.directory.entry">[[fs.class.directory.entry]]</a>
 ``` cpp
 namespace std::filesystem {
   class directory_entry {
   public:
     // [fs.dir.entry.cons], constructors and destructor
     directory_entry() noexcept = default;
     directory_entry(const directory_entry&) = default;
     directory_entry(directory_entry&&) noexcept = default;
+    explicit directory_entry(const filesystem::path& p);
+    directory_entry(const filesystem::path& p, error_code& ec);
     ~directory_entry();
+    // assignments
     directory_entry& operator=(const directory_entry&) = default;
     directory_entry& operator=(directory_entry&&) noexcept = default;
     // [fs.dir.entry.mods], modifiers
+    void assign(const filesystem::path& p);
+    void assign(const filesystem::path& p, error_code& ec);
+    void replace_filename(const filesystem::path& p);
+    void replace_filename(const filesystem::path& p, error_code& ec);
     void refresh();
     void refresh(error_code& ec) noexcept;
     // [fs.dir.entry.obs], observers
+    const filesystem::path& path() const noexcept;
+    operator const filesystem::path&() const noexcept;
     bool exists() const;
     bool exists(error_code& ec) const noexcept;
     bool is_block_file() const;
     bool is_block_file(error_code& ec) const noexcept;
     bool is_character_file() const;
     file_status status() const;
     file_status status(error_code& ec) const noexcept;
     file_status symlink_status() const;
     file_status symlink_status(error_code& ec) const noexcept;
     bool operator==(const directory_entry& rhs) const noexcept;
+ strong_ordering operator<=>(const directory_entry& rhs) const noexcept;
   private:
+ filesystem::path pathobject; // exposition only
     friend class directory_iterator;    // exposition only
   };
 }
 ```
 A `directory_entry` object stores a `path` object and may store
 additional objects for file attributes such as hard link count, status,
 symlink status, file size, and last write time.
+Implementations should store such additional file attributes during
+directory iteration if their values are available and storing the values
+would allow the implementation to eliminate file system accesses by
+`directory_entry` observer functions [[fs.op.funcs]]. Such stored file
+attribute values are said to be *cached*.
+[*Note 1*: For purposes of exposition, class `directory_iterator`
+[[fs.class.directory.iterator]] is shown above as a friend of class
 `directory_entry`. Friendship allows the `directory_iterator`
 implementation to cache already available attribute values directly into
 a `directory_entry` object without the cost of an unneeded call to
 `refresh()`. — *end note*]
 `std::filesystem::last_write_time` function. The code is portable to any
 implementation, regardless of whether or not it employs caching.
 — *end example*]
+#### Constructors <a id="fs.dir.entry.cons">[[fs.dir.entry.cons]]</a>
 ``` cpp
+explicit directory_entry(const filesystem::path& p);
+directory_entry(const filesystem::path& p, error_code& ec);
 ```
+*Effects:* Calls `refresh()` or `refresh(ec)`, respectively.
+*Ensures:* `path() == p` if no error occurs, otherwise
+`path() == filesystem::path()`.
 *Throws:* As specified in  [[fs.err.report]].
+#### Modifiers <a id="fs.dir.entry.mods">[[fs.dir.entry.mods]]</a>
 ``` cpp
+void assign(const filesystem::path& p);
+void assign(const filesystem::path& p, error_code& ec);
 ```
 *Effects:* Equivalent to `pathobject = p`, then `refresh()` or
 `refresh(ec)`, respectively. If an error occurs, the values of any
 cached attributes are unspecified.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
+void replace_filename(const filesystem::path& p);
+void replace_filename(const filesystem::path& p, error_code& ec);
 ```
 *Effects:* Equivalent to `pathobject.replace_filename(p)`, then
 `refresh()` or `refresh(ec)`, respectively. If an error occurs, the
 values of any cached attributes are unspecified.
 void refresh(error_code& ec) noexcept;
 ```
 *Effects:* Stores the current values of any cached attributes of the
 file `p` resolves to. If an error occurs, an error is
+reported [[fs.err.report]] and the values of any cached attributes are
+unspecified.
 *Throws:* As specified in  [[fs.err.report]].
+[*Note 1*: Implementations of `directory_iterator`
+[[fs.class.directory.iterator]] are prohibited from directly or
+indirectly calling the `refresh` function since it must access the
+external file system, and the objective of caching is to avoid
+unnecessary file system accesses. — *end note*]
+#### Observers <a id="fs.dir.entry.obs">[[fs.dir.entry.obs]]</a>
 Unqualified function names in the *Returns:* elements of the
 `directory_entry` observers described below refer to members of the
 `std::filesystem` namespace.
 ``` cpp
+const filesystem::path& path() const noexcept;
+operator const filesystem::path&() const noexcept;
 ```
 *Returns:* `pathobject`.
 ``` cpp
 bool exists() const;
 bool exists(error_code& ec) const noexcept;
 ```
+*Returns:* `exists(this->status())` or `exists(this->status(ec))`,
 respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_block_file() const;
 bool is_block_file(error_code& ec) const noexcept;
 ```
 *Returns:* `is_block_file(this->status())` or
+`is_block_file(this->status(ec))`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_character_file() const;
 bool is_character_file(error_code& ec) const noexcept;
 ```
 *Returns:* `is_character_file(this->status())` or
+`is_character_file(this->status(ec))`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_directory() const;
 bool is_directory(error_code& ec) const noexcept;
 ```
 *Returns:* `is_directory(this->status())` or
+`is_directory(this->status(ec))`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_fifo() const;
 bool is_fifo(error_code& ec) const noexcept;
 ```
+*Returns:* `is_fifo(this->status())` or `is_fifo(this->status(ec))`,
 respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_other() const;
 bool is_other(error_code& ec) const noexcept;
 ```
+*Returns:* `is_other(this->status())` or `is_other(this->status(ec))`,
 respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_regular_file() const;
 bool is_regular_file(error_code& ec) const noexcept;
 ```
 *Returns:* `is_regular_file(this->status())` or
+`is_regular_file(this->status(ec))`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_socket() const;
 bool is_socket(error_code& ec) const noexcept;
 ```
+*Returns:* `is_socket(this->status())` or `is_socket(this->status(ec))`,
+respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool is_symlink() const;
 bool is_symlink(error_code& ec) const noexcept;
 ```
 *Returns:* `is_symlink(this->symlink_status())` or
+`is_symlink(this->symlink_status(ec))`, respectively.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 uintmax_t file_size() const;
 ```
 *Returns:* `pathobject == rhs.pathobject`.
 ``` cpp
+strong_ordering operator<=>(const directory_entry& rhs) const noexcept;
 ```
+*Returns:* `pathobject <=> rhs.pathobject`.
+### Class `directory_iterator` <a id="fs.class.directory.iterator">[[fs.class.directory.iterator]]</a>
 An object of type `directory_iterator` provides an iterator for a
 sequence of `directory_entry` elements representing the path and any
+cached attribute values [[fs.class.directory.entry]] for each file in a
+directory or in an *implementation-defined* directory-like file type.
 [*Note 1*: For iteration into sub-directories, see class
+`recursive_directory_iterator` [[fs.class.rec.dir.itr]]. — *end note*]
 ``` cpp
 namespace std::filesystem {
   class directory_iterator {
   public:
     // [fs.dir.itr.members], member functions
     directory_iterator() noexcept;
     explicit directory_iterator(const path& p);
     directory_iterator(const path& p, directory_options options);
+    directory_iterator(const path& p, error_code& ec);
     directory_iterator(const path& p, directory_options options,
+                       error_code& ec);
     directory_iterator(const directory_iterator& rhs);
     directory_iterator(directory_iterator&& rhs) noexcept;
     ~directory_iterator();
     directory_iterator& operator=(const directory_iterator& rhs);
     directory_iterator& operator=(directory_iterator&& rhs) noexcept;
     const directory_entry& operator*() const;
     const directory_entry* operator->() const;
     directory_iterator&    operator++();
+    directory_iterator&    increment(error_code& ec);
     // other members as required by [input.iterators], input iterators
   };
 }
 ```
+`directory_iterator` meets the *Cpp17InputIterator* requirements
+[[input.iterators]].
 If an iterator of type `directory_iterator` reports an error or is
 advanced past the last directory element, that iterator shall become
 equal to the end iterator value. The `directory_iterator` default
 constructor shall create an iterator equal to the end iterator value,
 to a `path` object composed of the directory argument from which the
 iterator was constructed with filename of the directory entry appended
 as if by `operator/=`.
 Directory iteration shall not yield directory entries for the current
+(dot) and parent (dot-dot) directories.
 The order of directory entries obtained by dereferencing successive
 increments of a `directory_iterator` is unspecified.
 Constructors and non-const `directory_iterator` member functions store
+the values of any cached attributes [[fs.class.directory.entry]] in the
+`directory_entry` element returned by `operator*()`.
 `directory_iterator` member functions shall not directly or indirectly
 call any `directory_entry` `refresh` function.
 [*Note 2*: The exact mechanism for storing cached attribute values is
 not exposed to users. For exposition, class `directory_iterator` is
+shown in [[fs.class.directory.entry]] as a friend of class
 `directory_entry`. — *end note*]
 [*Note 3*: Programs performing directory iteration may wish to test if
 the path obtained by dereferencing a directory iterator actually exists.
 It could be a symbolic link to a non-existent file. Programs recursively
 construction of a `directory_iterator` for the directory, it is
 unspecified whether or not subsequently incrementing the iterator will
 ever result in an iterator referencing the removed or added directory
 entry. See POSIX `readdir_r`. — *end note*]
+#### Members <a id="fs.dir.itr.members">[[fs.dir.itr.members]]</a>
 ``` cpp
 directory_iterator() noexcept;
 ```
 *Effects:* Constructs the end iterator.
 ``` cpp
 explicit directory_iterator(const path& p);
 directory_iterator(const path& p, directory_options options);
+directory_iterator(const path& p, error_code& ec);
+directory_iterator(const path& p, directory_options options, error_code& ec);
 ```
 *Effects:* For the directory that `p` resolves to, constructs an
 iterator for the first element in a sequence of `directory_entry`
 elements representing the files in the directory, if any; otherwise the
 ``` cpp
 directory_iterator(const directory_iterator& rhs);
 directory_iterator(directory_iterator&& rhs) noexcept;
 ```
+*Ensures:* `*this` has the original value of `rhs`.
 ``` cpp
 directory_iterator& operator=(const directory_iterator& rhs);
 directory_iterator& operator=(directory_iterator&& rhs) noexcept;
 ```
 *Effects:* If `*this` and `rhs` are the same object, the member has no
 effect.
+*Ensures:* `*this` has the original value of `rhs`.
 *Returns:* `*this`.
 ``` cpp
 directory_iterator& operator++();
+directory_iterator& increment(error_code& ec);
 ```
 *Effects:* As specified for the prefix increment operation of Input
+iterators [[input.iterators]].
 *Returns:* `*this`.
 *Throws:* As specified in  [[fs.err.report]].
+#### Non-member functions <a id="fs.dir.itr.nonmembers">[[fs.dir.itr.nonmembers]]</a>
 These functions enable range access for `directory_iterator`.
 ``` cpp
 directory_iterator begin(directory_iterator iter) noexcept;
     // [fs.rec.dir.itr.members], constructors and destructor
     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();
     // [fs.rec.dir.itr.members], observers
       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();
 `directory_iterator` unless otherwise specified.
 [*Note 1*: If the directory structure being iterated over contains
 cycles then the end iterator may be unreachable. — *end note*]
+#### Members <a id="fs.rec.dir.itr.members">[[fs.rec.dir.itr.members]]</a>
 ``` cpp
 recursive_directory_iterator() noexcept;
 ```
 *Effects:* Constructs the end iterator.
 ``` cpp
 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
 ``` cpp
 (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.
+*Ensures:* `options() == options` for the signatures with a
 `directory_options` argument, otherwise
 `options() == directory_options::none`.
 *Throws:* As specified in  [[fs.err.report]].
 `recursive_directory_iterator(".")` rather than
 `recursive_directory_iterator("")`. — *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*]
 ``` cpp
 recursive_directory_iterator(const recursive_directory_iterator& rhs);
 ```
+*Ensures:*
 - `options() == rhs.options()`
 - `depth() == rhs.depth()`
 - `recursion_pending() == rhs.recursion_pending()`
 ``` cpp
 recursive_directory_iterator(recursive_directory_iterator&& rhs) noexcept;
 ```
+*Ensures:* `options()`, `depth()`, and `recursion_pending()` have the
+values that `rhs.options()`, `rhs.depth()`, and
 `rhs.recursion_pending()`, respectively, had before the function call.
 ``` cpp
 recursive_directory_iterator& operator=(const recursive_directory_iterator& rhs);
 ```
 *Effects:* If `*this` and `rhs` are the same object, the member has no
 effect.
+*Ensures:*
 - `options() == rhs.options()`
 - `depth() == rhs.depth()`
 - `recursion_pending() == rhs.recursion_pending()`
 ```
 *Effects:* If `*this` and `rhs` are the same object, the member has no
 effect.
+*Ensures:* `options()`, `depth()`, and `recursion_pending()` have the
+values that `rhs.options()`, `rhs.depth()`, and
 `rhs.recursion_pending()`, respectively, had before the function call.
 *Returns:* `*this`.
 ``` cpp
 *Throws:* Nothing.
 ``` cpp
 recursive_directory_iterator& operator++();
+recursive_directory_iterator& increment(error_code& ec);
 ```
 *Effects:* As specified for the prefix increment operation of Input
+iterators [[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
 directory currently being iterated over, and continue iteration over the
 parent directory.
 *Throws:* As specified in  [[fs.err.report]].
+*Remarks:* Any copies of the previous value of `*this` are no longer
+required to be dereferenceable nor to be in the domain of `==`.
 ``` cpp
 void disable_recursion_pending();
 ```
+*Ensures:* `recursion_pending() == false`.
 [*Note 4*: `disable_recursion_pending``()` is used to prevent unwanted
 recursion into a directory. — *end note*]
+#### Non-member functions <a id="fs.rec.dir.itr.nonmembers">[[fs.rec.dir.itr.nonmembers]]</a>
 These functions enable use of `recursive_directory_iterator` with
 range-based for statements.
 ``` cpp
 Filesystem operation functions query or modify files, including
 directories, in external storage.
 [*Note 1*: Because hardware failures, network failures, file system
+races [[fs.race.behavior]], and many other kinds of errors occur
 frequently in file system operations, users should be aware that any
 filesystem operation function, no matter how apparently innocuous, may
 encounter an error; see  [[fs.err.report]]. — *end note*]
 #### Absolute <a id="fs.op.absolute">[[fs.op.absolute]]</a>
 path absolute(const path& p);
 path absolute(const path& p, error_code& ec);
 ```
 *Effects:* Composes an absolute path referencing the same file system
+location as `p` according to the operating system [[fs.conform.os]].
 *Returns:* The composed path. The signature with argument `ec` returns
 `path()` if an error occurs.
 [*Note 1*: For the returned path, `rp`, `rp.is_absolute()` is `true`
 *Throws:* As specified in  [[fs.err.report]].
 [*Note 2*: To resolve symlinks, or perform other sanitization which
 might require queries to secondary storage, such as hard disks, consider
+`canonical` [[fs.op.canonical]]. — *end note*]
 [*Note 3*: Implementations are strongly encouraged to not query
 secondary storage, and not consider `!exists(p)` an
 error. — *end note*]
 `GetFullPathNameW`. — *end example*]
 #### Canonical <a id="fs.op.canonical">[[fs.op.canonical]]</a>
 ``` cpp
+path canonical(const path& p);
 path canonical(const path& p, error_code& ec);
 ```
+*Effects:* Converts `p` to an absolute path that has no symbolic link,
+dot, or dot-dot elements in its pathname in the generic format.
 *Returns:* A path that refers to the same file system object as
+`absolute(p)`. The signature with argument `ec` returns `path()` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
 *Remarks:* `!exists(p)` is an error.
 ```
 *Effects:* Equivalent to `copy(from, to, copy_options::none)`.
 ``` cpp
+void copy(const path& from, const path& to, error_code& ec);
 ```
 *Effects:* Equivalent to `copy(from, to, copy_options::none, ec)`.
 ``` cpp
 void copy(const path& from, const path& to, copy_options options);
 void copy(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:* Before the first use of `f` and `t`:
 - If
   ``` cpp
   `auto t = status(to)`.
 Effects are then as follows:
 - If `f.type()` or `t.type()` is an implementation-defined file
+  type [[fs.enum.file.type]], then the effects are
   *implementation-defined*.
 - Otherwise, an error is reported as specified in  [[fs.err.report]] if:
+  - `exists(f)` is `false`, or
+  - `equivalent(from, to)` is `true`, or
+  - `is_other(f) || is_other(t)` is `true`, or
+  - `is_directory(f) && is_regular_file(t)` is `true`.
 - Otherwise, if `is_symlink(f)`, then:
   - If `(options & copy_options::skip_symlinks) != copy_options::none`
     then return.
   - Otherwise if
     ``` cpp
     `(options & copy_options::create_hard_links) != copy_options::none`,
     then create a hard link to the source file.
   - Otherwise, if `is_directory(t)`, then
     `copy_file(from, to/from.filename(), options)`.
   - Otherwise, `copy_file(from, to, options)`.
+- Otherwise, if
+  ``` cpp
+  is_directory(f) &&
+  (options & copy_options::create_symlinks) != copy_options::none
+  ```
+  then report an error with an `error_code` argument equal to
+  `make_error_code(errc::is_a_directory)`.
 - Otherwise, if
   ``` cpp
   is_directory(f) &&
   ((options & copy_options::recursive) != copy_options::none ||
    options == copy_options::none)
   ```
   then:
+  - If `exists(t)` is `false`, then `create_directory(to, from)`.
   - Then, iterate over the files in `from`, as if by
     ``` cpp
     for (const directory_entry& x : directory_iterator(from))
+      copy(x.path(), to/x.path().filename(),
+           options | copy_options::in-recursive-copy);
     ```
+    where *`in-recursive-copy`* is a bitmask element of `copy_options`
+    that is not one of the elements in  [[fs.enum.copy.opts]].
 - Otherwise, for the signature with argument `ec`, `ec.clear()`.
 - Otherwise, no effects.
 *Throws:* As specified in  [[fs.err.report]].
     file3
 ```
 — *end example*]
+#### Copy file <a id="fs.op.copy.file">[[fs.op.copy.file]]</a>
 ``` cpp
 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]].
 ``` cpp
 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:
+- Report an error as specified in  [[fs.err.report]] if:
+ - `is_regular_file(from)` is `false`, or
+  - `exists(to)` is `true` and `is_regular_file(to)` is `false`, or
+  - `exists(to)` is `true` and `equivalent(from, to)` is `true`, or
+  - `exists(to)` is `true` and
     ``` cpp
     (options & (copy_options::skip_existing |
                 copy_options::overwrite_existing |
                 copy_options::update_existing)) == copy_options::none
     ```
 - Otherwise, copy the contents and attributes of the file `from`
   resolves to, to the file `to` resolves to, if:
+  - `exists(to)` is `false`, or
   - `(options & copy_options::overwrite_existing) != copy_options::none`,
     or
   - `(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]].
 - 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)`.
+#### Copy symlink <a id="fs.op.copy.symlink">[[fs.op.copy.symlink]]</a>
 ``` cpp
 void copy_symlink(const path& existing_symlink, const path& new_symlink);
 void copy_symlink(const path& existing_symlink, const path& new_symlink,
                   error_code& ec) noexcept;
 respectively, where in each case *`function`* is `create_symlink` or
 `create_directory_symlink` as appropriate.
 *Throws:* As specified in  [[fs.err.report]].
+#### Create directories <a id="fs.op.create.directories">[[fs.op.create.directories]]</a>
 ``` cpp
 bool create_directories(const path& p);
+bool create_directories(const path& p, error_code& ec);
 ```
+*Effects:* Calls `create_directory()` for each element of `p` that does
 not exist.
+*Returns:* `true` if a new directory was created for the directory `p`
+resolves to, otherwise `false`.
+*Throws:* As specified in  [[fs.err.report]].
+*Complexity:* 𝑂(n) where *n* is the number of elements of `p`.
+#### Create directory <a id="fs.op.create.directory">[[fs.op.create.directory]]</a>
 ``` cpp
 bool create_directory(const path& p);
 bool create_directory(const path& p, error_code& ec) noexcept;
 ```
+*Effects:* Creates the directory `p` resolves to, as if by POSIX `mkdir`
+with a second argument of `static_cast<int>(perms::all)`. If `mkdir`
+fails because `p` resolves to an existing directory, no error is
+reported. Otherwise on failure an error is reported.
+*Returns:* `true` if a new directory was created, otherwise `false`.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 bool create_directory(const path& p, const path& existing_p);
 bool create_directory(const path& p, const path& existing_p, error_code& ec) noexcept;
 ```
+*Effects:* Creates the directory `p` resolves to, with attributes copied
+from directory `existing_p`. The set of attributes copied is operating
+system dependent. If `mkdir` fails because `p` resolves to an existing
+directory, no error is reported. Otherwise on failure an error is
+reported.
 [*Note 1*: For POSIX-based operating systems, the attributes are those
 copied by native API `stat(existing_p.c_str(), &attributes_stat)`
 followed by `mkdir(p.c_str(), attributes_stat.st_mode)`. For
 Windows-based operating systems, the attributes are those copied by
 native API
 `CreateDirectoryExW(existing_p.c_str(), p.c_str(), 0)`. — *end note*]
+*Returns:* `true` if a new directory was created with attributes copied
+from directory `existing_p`, otherwise `false`.
 *Throws:* As specified in  [[fs.err.report]].
+#### Create directory symlink <a id="fs.op.create.dir.symlk">[[fs.op.create.dir.symlk]]</a>
 ``` cpp
 void create_directory_symlink(const path& to, const path& new_symlink);
 void create_directory_symlink(const path& to, const path& new_symlink,
                               error_code& ec) noexcept;
 ```
 *Effects:* Establishes the postcondition, as if by POSIX `symlink()`.
+*Ensures:* `new_symlink` resolves to a symbolic link file that contains
+an unspecified representation of `to`.
 *Throws:* As specified in  [[fs.err.report]].
 [*Note 1*: Some operating systems require symlink creation to identify
 that the link is to a directory. Portable code should use
 [*Note 2*: Some operating systems do not support symbolic links at all
 or support them only for regular files. Some file systems (such as the
 FAT file system) do not support symbolic links regardless of the
 operating system. — *end note*]
+#### Create hard link <a id="fs.op.create.hard.lk">[[fs.op.create.hard.lk]]</a>
 ``` cpp
 void create_hard_link(const path& to, const path& new_hard_link);
 void create_hard_link(const path& to, const path& new_hard_link,
                                       error_code& ec) noexcept;
 ```
 *Effects:* Establishes the postcondition, as if by POSIX `link()`.
+*Ensures:*
 - `exists(to) && exists(new_hard_link) && equivalent(to, new_hard_link)`
 - The contents of the file or directory `to` resolves to are unchanged.
 *Throws:* As specified in  [[fs.err.report]].
 support them only for regular files. Some file systems (such as the FAT
 file system) do not support hard links regardless of the operating
 system. Some file systems limit the number of links per
 file. — *end note*]
+#### Create symlink <a id="fs.op.create.symlink">[[fs.op.create.symlink]]</a>
 ``` cpp
 void create_symlink(const path& to, const path& new_symlink);
 void create_symlink(const path& to, const path& new_symlink,
                     error_code& ec) noexcept;
 ```
 *Effects:* Establishes the postcondition, as if by POSIX `symlink()`.
+*Ensures:* `new_symlink` resolves to a symbolic link file that contains
+an unspecified representation of `to`.
 *Throws:* As specified in  [[fs.err.report]].
 [*Note 1*: Some operating systems do not support symbolic links at all
 or support them only for regular files. Some file systems (such as the
 FAT file system) do not support symbolic links regardless of the
 operating system. — *end note*]
+#### Current path <a id="fs.op.current.path">[[fs.op.current.path]]</a>
 ``` cpp
 path current_path();
 path current_path(error_code& ec);
 ```
 [*Note 1*: The `current_path()` name was chosen to emphasize that the
 returned value is a path, not just a single directory
 name. — *end note*]
 [*Note 2*: The current path as returned by many operating systems is a
+dangerous global variable. It may be changed unexpectedly by third-party
+or system library functions, or by another thread. — *end note*]
 ``` cpp
 void current_path(const path& p);
 void current_path(const path& p, error_code& ec) noexcept;
 ```
 *Effects:* Establishes the postcondition, as if by POSIX `chdir()`.
+*Ensures:* `equivalent(p, current_path())`.
 *Throws:* As specified in  [[fs.err.report]].
 [*Note 3*: The current path for many operating systems is a dangerous
 global state. It may be changed unexpectedly by a third-party or system
 ``` cpp
 bool equivalent(const path& p1, const path& p2);
 bool equivalent(const path& p1, const path& p2, error_code& ec) noexcept;
 ```
+*Returns:* `true`, if `p1` and `p2` resolve to the same file system
+entity, otherwise `false`. The signature with argument `ec` returns
+`false` if an error occurs.
 Two paths are considered to resolve to the same file system entity if
 two candidate entities reside on the same device at the same location.
+[*Note 1*: On POSIX platforms, this is determined as if by the values
+of the POSIX `stat` class, obtained as if by `stat()` for the two paths,
+having equal `st_dev` values and equal `st_ino` values. — *end note*]
+*Remarks:* `!exists(p1) || !exists(p2)` is an error.
 *Throws:* As specified in  [[fs.err.report]].
 #### Exists <a id="fs.op.exists">[[fs.op.exists]]</a>
 *Returns:* `exists(s)`.
 *Throws:* As specified in  [[fs.err.report]].
+#### File size <a id="fs.op.file.size">[[fs.op.file.size]]</a>
 ``` cpp
 uintmax_t file_size(const path& p);
 uintmax_t file_size(const path& p, error_code& ec) noexcept;
 ```
+*Effects:* If `exists(p)` is `false`, an error is
+reported [[fs.err.report]].
 *Returns:*
+- If `is_regular_file(p)`, the size in bytes of the file `p` resolves
+  to, determined as if by the value of the POSIX `stat` class member
+ `st_size` obtained as if by POSIX `stat()`.
 - Otherwise, the result is *implementation-defined*.
 The signature with argument `ec` returns `static_cast<uintmax_t>(-1)` if
 an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Hard link count <a id="fs.op.hard.lk.ct">[[fs.op.hard.lk.ct]]</a>
 ``` cpp
 uintmax_t hard_link_count(const path& p);
 uintmax_t hard_link_count(const path& p, error_code& ec) noexcept;
 ```
 *Returns:* The number of hard links for `p`. The signature with argument
 `ec` returns `static_cast<uintmax_t>(-1)` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Is block file <a id="fs.op.is.block.file">[[fs.op.is.block.file]]</a>
 ``` cpp
 bool is_block_file(file_status s) noexcept;
 ```
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Is character file <a id="fs.op.is.char.file">[[fs.op.is.char.file]]</a>
 ``` cpp
 bool is_character_file(file_status s) noexcept;
 ```
 `is_character_file(status(p, ec))`, respectively.
 The signature with argument `ec` returns `false` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Is directory <a id="fs.op.is.directory">[[fs.op.is.directory]]</a>
 ``` cpp
 bool is_directory(file_status s) noexcept;
 ```
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Is empty <a id="fs.op.is.empty">[[fs.op.is.empty]]</a>
 ``` cpp
 bool is_empty(const path& p);
+bool is_empty(const path& p, error_code& ec);
 ```
 *Effects:*
 - Determine `file_status s`, as if by `status(p)` or `status(p, ec)`,
     occurred.
   - Otherwise, return `sz == 0`.
 *Throws:* As specified in  [[fs.err.report]].
+#### Is fifo <a id="fs.op.is.fifo">[[fs.op.is.fifo]]</a>
 ``` cpp
 bool is_fifo(file_status s) noexcept;
 ```
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Is other <a id="fs.op.is.other">[[fs.op.is.other]]</a>
 ``` cpp
 bool is_other(file_status s) noexcept;
 ```
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Is regular file <a id="fs.op.is.regular.file">[[fs.op.is.regular.file]]</a>
 ``` cpp
 bool is_regular_file(file_status s) noexcept;
 ```
 ```
 *Returns:* `is_regular_file(status(p))`.
 *Throws:* `filesystem_error` if `status(p)` would throw
+`filesystem_error`.
 ``` cpp
 bool is_regular_file(const path& p, error_code& ec) noexcept;
 ```
 between cases, call the `status` function directly. — *end note*]
 *Returns:* `is_regular_file(status(p, ec))`. Returns `false` if an error
 occurs.
+#### Is socket <a id="fs.op.is.socket">[[fs.op.is.socket]]</a>
 ``` cpp
 bool is_socket(file_status s) noexcept;
 ```
 respectively. The signature with argument `ec` returns `false` if an
 error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Is symlink <a id="fs.op.is.symlink">[[fs.op.is.symlink]]</a>
 ``` cpp
 bool is_symlink(file_status s) noexcept;
 ```
 `is_symlink(symlink_status(p, ec))`, respectively. The signature with
 argument `ec` returns `false` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Last write time <a id="fs.op.last.write.time">[[fs.op.last.write.time]]</a>
 ``` cpp
 file_time_type last_write_time(const path& p);
 file_time_type last_write_time(const path& p, error_code& ec) noexcept;
 ```
 *Returns:* The time of last data modification of `p`, determined as if
+by the value of the POSIX `stat` class member `st_mtime` obtained as if
+by POSIX `stat()`. The signature with argument `ec` returns
 `file_time_type::min()` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
 ``` cpp
 void permissions(const path& p, perms prms, perm_options opts=perm_options::replace);
 void permissions(const path& p, perms prms, error_code& ec) noexcept;
 void permissions(const path& p, perms prms, perm_options opts, error_code& ec);
 ```
+*Preconditions:* Exactly one of the `perm_options` constants `replace`,
 `add`, or `remove` is present in `opts`.
 *Remarks:* The second signature behaves as if it had an additional
 parameter `perm_options` `opts` with an argument of
 `perm_options::replace`.
 or `path()` at the first error occurrence, if any.
 *Throws:* As specified in  [[fs.err.report]].
+#### Read symlink <a id="fs.op.read.symlink">[[fs.op.read.symlink]]</a>
 ``` cpp
 path read_symlink(const path& p);
 path read_symlink(const path& p, error_code& ec);
 ```
 as if by POSIX `remove()`.
 [*Note 1*: A symbolic link is itself removed, rather than the file it
 resolves to. — *end note*]
+*Ensures:* `exists(symlink_status(p))` is `false`.
 *Returns:* `false` if `p` did not exist, otherwise `true`. The signature
 with argument `ec` returns `false` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
+#### Remove all <a id="fs.op.remove.all">[[fs.op.remove.all]]</a>
 ``` cpp
 uintmax_t remove_all(const path& p);
+uintmax_t remove_all(const path& p, error_code& ec);
 ```
 *Effects:* Recursively deletes the contents of `p` if it exists, then
 deletes file `p` itself, as if by POSIX `remove()`.
 [*Note 1*: A symbolic link is itself removed, rather than the file it
 resolves to. — *end note*]
+*Ensures:* `exists(symlink_status(p))` is `false`.
 *Returns:* The number of files removed. The signature with argument `ec`
 returns `static_cast< uintmax_t>(-1)` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
 — *end note*]
 *Throws:* As specified in  [[fs.err.report]].
+#### Resize file <a id="fs.op.resize.file">[[fs.op.resize.file]]</a>
 ``` cpp
 void resize_file(const path& p, uintmax_t new_size);
 void resize_file(const path& p, uintmax_t new_size, error_code& ec) noexcept;
 ```
+*Effects:* Causes the size that would be returned by `file_size(p)` to
+be equal to `new_size`, as if by POSIX `truncate()`.
 *Throws:* As specified in  [[fs.err.report]].
 #### Space <a id="fs.op.space">[[fs.op.space]]</a>
 ``` cpp
 space_info space(const path& p);
 space_info space(const path& p, error_code& ec) noexcept;
   - Otherwise, if the attributes indicate a fifo or pipe file, as if by
     POSIX `S_ISFIFO`, returns `file_status(file_type::fifo, prms)`.
   - Otherwise, if the attributes indicate a socket, as if by POSIX
     `S_ISSOCK`, returns `file_status(file_type::socket, prms)`.
   - 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.
   - 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.
+#### Status known <a id="fs.op.status.known">[[fs.op.status.known]]</a>
 ``` cpp
 bool status_known(file_status s) noexcept;
 ```
 *Returns:* `s.type() != file_type::none`.
+#### Symlink status <a id="fs.op.symlink.status">[[fs.op.symlink.status]]</a>
 ``` cpp
 file_status symlink_status(const path& p);
 file_status symlink_status(const path& p, error_code& ec) noexcept;
 ```
 *Remarks:* Pathname resolution terminates if `p` names a symbolic link.
 *Throws:* As specified in  [[fs.err.report]].
+#### Temporary directory path <a id="fs.op.temp.dir.path">[[fs.op.temp.dir.path]]</a>
 ``` cpp
 path temp_directory_path();
 path temp_directory_path(error_code& ec);
 ```
+Let `p` be an unspecified directory path suitable for temporary files.
+*Effects:* If `exists(p)` is `false` or `is_directory(p)` is `false`, an
+error is reported [[fs.err.report]].
+*Returns:* The path `p`. The signature with argument `ec` returns
 `path()` if an error occurs.
 *Throws:* As specified in  [[fs.err.report]].
 [*Example 1*: For POSIX-based operating systems, an implementation
 in the list TMPDIR, TMP, TEMP, TEMPDIR, or if none of these are found,
 `"/tmp"`. For Windows-based operating systems, an implementation might
 return the path reported by the Windows `GetTempPath` API
 function. — *end example*]
+#### Weakly canonical <a id="fs.op.weakly.canonical">[[fs.op.weakly.canonical]]</a>
 ``` cpp
 path weakly_canonical(const path& p);
 path weakly_canonical(const path& p, error_code& ec);
 ```
 *Returns:* `p` with symlinks resolved and the result
+normalized [[fs.path.generic]].
 *Effects:* Using `status(p)` or `status(p, ec)`, respectively, to
 determine existence, return a path composed by `operator/=` from the
+result of calling `canonical()` with a path argument composed of the
+leading elements of `p` that exist, if any, followed by the elements of
+`p` that do not exist, if any. For the first form, `canonical()` is
+called without an `error_code` argument. For the second form,
+`canonical()` is called with `ec` as an `error_code` argument, and
+`path()` is returned at the first error occurrence, if any.
+*Ensures:* The returned path is in normal form [[fs.path.generic]].
+*Remarks:* Implementations should avoid unnecessary normalization such
+as when `canonical` has already been called on the entirety of `p`.
 *Throws:* As specified in  [[fs.err.report]].

Diff to HTML by rtfpessoa