Proposed Resolution of C++17 National Body Comments for Filesystems(R0)

US 52; 27.10.8.4.5 [path.modifiers] ¶5: remove_filename() postcondition is not by itself a definition
Status: Accept with modifications

Also see LWG LWG 2665.

Change 27.10.8.4.5 [path.modifiers] ¶5:

Postcondition:!has_filename().

Effects: If has_filename() then remove the minimum number of trailing characters from pathname such that there is one less element in [begin(), end()). Otherwise, no effect.

US 53; 27.10.8.4.5 [path.modifiers] ¶7: remove_filename()'s name does not correspond to its behavior
Status: Open

Because of a possible trailing "/", this comment is technically correct. The real question (for the full LWG) is do we want to make a name change at this late date for a name that is "good enough".

This issue probably needs to be resolved before C++17 ships, since a name change is a breaking change.

Bikeshed: remove_last_element() rather than the suggested remove_component().

Caution: "remove_filename" appears at least seven times in sub-clause 27.10. All will need to be changed if the name changes.

Caution: "replace_filename" presumably also would need to be renamed.

 

US 54; 27.10.8.4.5 [path.modifiers] ¶10: remove_filename() is broken
Status: Open

Need to resolve US 53 first.

US 60; 27.10.8.4.9 [path.decompose] ¶6: path("/foo/").filename()==path(".") is surprising
Status: Open

US 55; 27.10.8.4.5 [path.modifiers] ¶11: replace_extension()'s use of path as parameter is inappropriate
Status: Accept with modifications

The SG believes path is the appropriate parameter type, but that the standard needs to clarify class path usage.

Change 27.10.8 [class.path] ¶1:

An object of class path represents a path (27.10.4.17) and contains a pathname (27.10.4.18). 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: Class path is used to abstract away the differences between the string types used by different operating systems to represent pathnames, and to perform conversions between encodings when necessary. — end note]

SG should review wording; "abstract away" was added during editing, rather than the previously agreed upon "support".

US 56; 27.10.8.4.5 [path.modifiers] ¶11.2: Remove replace_extension()'s conditional addition of period
Status: Reject

The SG presented such a proposal to the Library Evolution Working group in Issaquah, including a number of examples (See Nico's paper). There was no consensus for change. See the LEWG notes.

US 57; 27.10.8.4.8 [path.compare] ¶2: On Windows, absolute paths will sort in among relative paths
Status: Reject

Insufficient motivation for change.  Billy O'Neal will open an issue for an unrelated concern discovered while processing this comment. See LWG nnnn.

US 58; 27.10.8.4.9 [path.decompose] ¶5: parent_path() behavior for root paths is useless
Status: Accept with modifications

Change [path.decompose]:

path parent_path() const;

-?- Let parentEnd be an instance of path::iterator, initialized as follows:

• if has_relative_path(), from --end()
• otherwise, from end()

-5- Returns: (empty() || begin() == --end()) ? path() : pp, where pp is a path constructed as if by starting with an empty path and successively applying operator/= for each element in the range [begin(), --end()parentEnd).

US 59; 27.10.8.4.9 [path.decompose] ¶6: filename() returning path for single path components is bizarre
Status: Reject

path is filesystem's vocabulary type for both full paths and for path components, in the same sense that std::string might be used as the vocabulary type for both sentences and the words in the sentences. See US 55 for further discussion.

US 61; 27.10.8.4.9 [path.decompose] ¶8: Leading dots in filename() should not begin an extension
Status: Open

Beman needs to coordinate with Nico to apply LEWG guidance.

Cases that seem worth considering, with suggested decompositions:

path p	p.stem()	p.extension()
".bashrc"	".bashrc"	""
"..abc"	"..abc"	""
"...abc"	"...abc"	""
"abc..def"	"abc"	"..def"
"abc...def"	"abc"	"...def"

Change 27.10.8.4.9 [path.decompose] ¶ 8:

path stem() const;

Returns: if filename() contains a period but does not consist solely of one or two periods other than in a sequence of one or more beginning periods, returns the substring of filename() starting at its beginning and ending with the character before the last period first period of the last sequence of one or more periods. Otherwise, returns filename().

Change 27.10.8.4.9 [path.decompose] ¶ 10:

path extension() const;

Returns: if filename() contains a period but does not consist solely of one or two periods other than in a sequence of one or more beginning periods, returns the substring of filename() starting at the beginning of the rightmost sequence of periods and for the remainder of the path. Otherwise, returns an empty path object.

US 62; 27.10.8.4.9 [path.decompose] ¶11: It is important that stem()+extension()==filename()
Status: Open

Yes, it is important. But the note in ¶11 already says exactly that, so the question becomes "Should we make that part of the note normative?"

Saying that normatively would be a second way of saying what is already specified behavior, and saying the same normative thing twice is not good standardese. No proposed wording.

Review notes, and result of the LEWG vote.

US 63; 27.10.8.4.11 ¶1: lexically_normal() inconsistently treats trailing "/" but not "/.." as directory
Status: Open

Need proposed wording for the Proposed change "Append the /. in all cases known to name directories (if it is in fact necessary)".

We can now resolve this in light of LEWG vote.

US 185; 27.10.7: Fold error_code and non-error_code signatures into one signature
Status: Reject

Does not handle one signature being noexcept(true) and the other noexcept(false), and many other problems. Even the submitter is no longer in favor. See LWG list thread "[filesystem] US-185 Eliminating dual signatures for operational functions", October 25, 2016.

FI 14; 27.10.12.3: directory_entry comparisons are members
Status: Reject

This is LWG issue 2761, which has been closed as NAD.

US 73, CA 2; 27.10.8.1 [path.generic]: root-name is effectively implementation defined
Status: Accept with modifications

Change [path.generic]:

root-name:
An operating system dependent name that identifies the starting location for absolute paths. If the operating system does not define at least one root-name, then the implementation defines a root-name. Implementations are permitted to define additional root-names. [ Note: Many operating systems define a name beginning with two directory-separator characters as a root-name that identifies network or other resource locations. Some operating systems define a single letter followed by a colon as a drive specifier – a root-name identifying a specific device such as a disk drive. —end note ]

Add a new paragraph at the end of [path.generic]:

If root-name is otherwise ambiguous, the possibility with the longest sequence of characters is chosen. [ Note: 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 ]

US 74, CA 3; 27.10.8 [class.path]: The term “pathname” is ambiguous in some contexts
Status: Accept with modifications

SG needs to review the proposed wording for US-74/CA-3.

Discussion:

Many operations on filesystem::path are defined in terms of its exposition-only pathname member, which is defined implicitly by path::native() as the native format path. However, the native format need not be compatible with lexical operations like, for example, path::root_name() and path::extension().

The proposed resolution below clarifies the distinct role played by the += operator as mentioned in US 44 and addresses US 74/CA 3 (with a more extensive resolution).

See P0430R1 Section 2.1, for additional rationale. Beman needs to check with Jason to verify P0430R1 now just refers to US 74/CA 3 here for proposed wording.

Proposed resolution:

Remove In the [class.path] synopsis, remove the private (exposition-only) member from class path:

private:
  string_type pathname; // exposition only

Change [path.fmt.cvt]:

Option A; from Davis:

[ Note: The format conversions described in this section are not applied on POSIX- or Windows-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.
— Paths for regular files and paths for directories share the same syntax.

—end note ]

Option B; from Beman:

[ Note: The format conversions described in this section are usually not applied on POSIX- or Windows-based operating systems because on these systems:

— The generic format is acceptable as a native path.
— There is usually no need to distinguish between native format and generic format in function arguments.
— Paths for regular files and paths for directories share the same syntax.

Even on these operating systems, the format conversions may be applied for pathnames with implementation-defined root-names ([path.generic]).

—end note ]

SG needs to choose between Option A or Option B.

Several functions are defined to accept detected-format character sequence arguments that represent paths using either the generic pathname format grammar ([path.generic]) or the native pathname format ([fs.def.native]). Such an argument is taken to be in the generic format if and only if it matches the generic format but is not acceptable to the operating system as a native path.

Function arguments that take character sequences representing paths may use the generic pathname format grammar (27.10.8.1) or the native pathname format (27.10.4.11). If and only if such arguments are in the generic format and the generic format is not acceptable to the operating system as a native path, conversion to native format shall be performed during the processing of the argument.

[ Note: 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 disambiguation is required is permitted to distinguish between the formats. —end note ]

Beman is concerned about the following paragraph; his markup of text from Davis may be in error:

• Would s/Define G(n) and N(g) as the functions/Let G and N be the implementation's functions/ be clearer?

• Are some of the '=' supposed to be '=='?

Pathnames are converted as needed between the generic and native formats in an operating-system-dependent manner. Define G(n) and N(g) as the functions that convert to the generic and native formats respectively. If g=G(n) for some n, then G(N(g))=g; if n=N(g) for some g, then N(G(n))=n. [ Note: Neither G nor N need be invertible. —end note ]

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.

When a path is constructed from or is assigned a single representation separate from any path, the other representation is selected by the appropriate conversion function (G or N).

When the (new) value p of one representation of a path is derived from the representation of that or another path, a value q is chosen for 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: If q is the result of converting any path at all, it is the result of converting p.—end note ]

[SG note: P0430R1 (for US 75/CA 4) adds support for explicitly specifying the format to use, at least in the constructor.]

Change [path.construct]:

path(const path& p);
path(path&& p) noexcept;

Effects: Constructs an object of class path having the same native and generic format pathnames as p with pathname having the original value of p.pathname. In the second form, p is left in a valid but unspecified state.

path(string_type&& source);

Effects: Constructs an object of class path for which the pathname in the detected-format  of source has with pathname having the original value of source ([path.fmt.cvt]). source is left in a valid but unspecified state.

template <class Source>
path(const Source& source);
template <class InputIterator>
path(InputIterator first, InputIterator last);

Effects: Let s be the effective range of source ([path.req]) or the range [first, last), with the encoding converted if required ([path.cvt]). Finds the detected-format of s ([path.fmt.cvt]) and constructs an object of class path for which the pathname in that format is s.  Constructs an object of class path, storing the effective range of source (27.10.8.3) or the range [first, last) in pathname, converting format and encoding if required (27.10.8.2).

template <class Source>
path(const Source& source, const locale& loc);
template <class InputIterator>
path(InputIterator first, InputIterator last, const locale& loc);

Requires: The value type of Source and InputIterator is char.

 Effects:  Constructs an object of class path, storing the effective range of source or the range [first, last) in pathname, after converting format if required and 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 (27.10.4.10) 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 ([path.fmt.cvt]) and constructs an object of class path for which the pathname in that format is s.

In the example in [path.fmt.cvt] ¶ 7.2, change "pathname" to normal font rather than code font.

Change [path.assign]:

path& operator=(const path& p);

Effects: If *this and p are the same object, has no effect. Otherwise, sets the native and generic format pathnames to those of p modifies pathname to have the original value of p.pathname.

Returns: *this.

path& operator=(path&& p) noexcept;

Effects: If *this and p are the same object, has no effect. Otherwise, sets the native and generic format pathnames to those of p modifies pathname to have the original value of p.pathname. p is left in a valid but unspecified state. [ Note: A valid implementation is swap(p). —end note ]

Returns: *this.

path& operator=(string_type&& source);
path& assign(string_type&& source);

Effects: Sets the native and generic format pathnames to those of source Modifies pathname to have the original value of source. source is left in a valid but unspecified state.

Returns: *this.

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);

Effects: Let s be the effective range of source ([path.req]) or the range [first, last), with the encoding converted if required ([path.cvt]). Finds the detected-format of s and sets the pathname in that format to s ([path.fmt.cvt]). Stores the effective range of source (27.10.8.3) or the range [first, last) in pathname, converting format and encoding if required (27.10.8.2).

Returns: *this.

path& operator/=(const path& p);

Effects: If equivalent to has_filename() || !has_root_directory() && is_absolute(), then appends path::preferred_separator to the generic format pathname. [ Example: path("//host")/"foo" and path("//host/")/"foo" both equal "//host/foo". —end example ]

 Appends path::preferred_separator to pathname unless:

— an added directory-separator would be redundant, or

— an added directory-separator would change a relative path into an absolute path [Note: An empty path is relative.—end note ] , or

— p.empty() is true, or

— *p.native().cbegin() is a directory-separator.

Then appends p.native() to the native format pathname  pathname.

Returns: *this.

[SG note: this proposed wording depends on LWG 2732 and the recently proposed definition of has_filename() and will change again to address LWG 2664 and US 77/CA 6. It already, simply by ignoring p entirely until such time, addresses US 51.]

Change [path.modifiers]:

path& make_preferred();

Effects: Each directory-separator is converted to preferred-separator in the generic format pathname.

[SG note: the existing definition of remove_filename() is broken; it is expected to be rewritten.]

Change [path.modifiers]:

path& replace_extension(const path& replacement = path());

Effects: pathname (the stored path) is modified as follows:

— Any existing extension()(27.10.8.4.9) is removed from the generic format pathname stored path, then

— If replacement is not empty and does not begin with a dot character, a dot character is appended to the generic format pathname stored path, then

— operator+=(replacement); replacement is concatenated to the stored path.

Returns *this.

Change [path.modifiers]:

void swap(path& rhs) noexcept;

Effects: Swaps the contents (in all formats) of the two paths pathname and rhs.pathname.

Change [path.native.obs]:

const string_type& native() const noexcept;

Returns: The native format pathname pathname.

const value_type* c_str() const noexcept;

Returns: Equivalent to native().c_str() pathname.c_str().

operator string_type() const;

Returns: native() pathname.

[ Note: Conversion to string_type is provided so that an object of class path can be given as an argument to existing standard library file stream constructors and open functions. —end note ]

template <class EcharT, class traits = char_traits<EcharT>,
          class Allocator = allocator<EcharT>>
  basic_string<EcharT, traits, Allocator>
    string(const Allocator& a = Allocator()) const;

Returns: native() pathname.

Remarks: All memory allocation, including for the return value, shall be performed by a. Conversion, if any, is specified by 27.10.8.2.

Change [path.generic.obs]:

template <class EcharT, class traits = char_traits<EcharT>,
          class Allocator = allocator<EcharT>>
  basic_string<EcharT, traits, Allocator>
    generic_string(const Allocator& a = Allocator()) const;

Returns: The generic format pathname pathname, reformatted according to the generic pathname format (27.10.8.1).

Remarks: All memory allocation, including for the return value, shall be performed by a. Conversion, if any, is specified by 27.10.8.2.

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 generic format pathname pathname, reformatted according to the generic pathname format (27.10.8.1).

Remarks: Conversion, if any, is specified by 27.10.8.2. The encoding of the string returned by generic_u8string() is always UTF-8.

Change [path.decompose]:

path root_name() const;

Returns: root-name, if the generic format pathname pathname includes root-name, otherwise path().

path root_directory() const;

Returns: root-directory, if the generic format pathname pathname includes root-directory, otherwise path().

...

path relative_path() const;

Returns: A path composed from the generic format pathname pathname, if !empty(), beginning with the first filename after root-path. Otherwise, path().

...

[SG note: the new definition of filename() needs to refer to the generic format.]

path stem() const;

Returns: Let f be the generic format pathname for filename(). Returns a path whose generic format pathname is

- f, if it contains no periods or consists solely of one or two periods;

- otherwise, the prefix of f ending before its last period.

[SG note: we intend to change this paragraph to not count the first character as a period.]

Returns: if filename() contains a period but does not consist solely of one or two periods, returns the substring of filename() starting at its beginning and ending with the character before the last period. Otherwise, returns filename().

[ Example:

std::cout << path("/foo/bar.txt").stem(); // outputs "bar"
path p = "foo.bar.baz.tar";
for (; !p.extension().empty(); p = p.stem())
std::cout << p.extension() << ’\n’;
// outputs: .tar
// .baz
// .bar

—end example ]

path extension() const;

Returns: a path whose generic format pathname is the suffix of the generic format pathname for filename() not included in stem(). if filename() contains a period but does not consist solely of one or two periods, returns the substring of filename() starting at the rightmost period and for the remainder of the path. Otherwise, returns an empty path object.

Remarks: Implementations are permitted to define additional behavior for file systems which append additional elements to extensions, such as alternate data streams or partitioned dataset names.

[ Example:

std::cout << path("/foo/bar.txt").extension(); // outputs ".txt"
std::cout << path("/foo/bar").extension();     // outputs ""

—end example ]

[ Note: The period is included in the return value so that it is possible to distinguish between no extension and an empty extension. Also note that for a path p, p.stem()+p.extension() == p.filename(). —end note ]

Change [path.query]:

bool empty() const noexcept;

Returns: true if the generic format pathname is empty, else false pathname.empty().

...

bool is_absolute() const;

Returns: true if the native format pathname pathname contains an absolute path (27.10.4.1), else false.

[ Example: path("/").is_absolute() is true for POSIX-based operating systems, and false for Windows-based operating systems. —end example ]

Change [path.gen]:

path lexically_normal() const;

Returns: a path whose generic format pathname is the normal form ([fs.def.normal.form]) of the generic format pathname of *this *this in normal form ([fs.def.normal.form]).

Change [path.itr]:

Path iterators iterate over the elements of the generic format pathname pathname in the generic format (27.10.8.1).

A path::iterator is a constant iterator satisfying all the requirements of a bidirectional iterator (24.2.6) 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 generic format pathname pathname in the generic format, the forward traversal order is as follows:

...

Change [fs.op.canonical]:

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 generic format pathname ".", or ".." elements.

...

Change [fs.op.current_path]:

path current_path();
path current_path(error_code& ec);

Returns: The absolute path of the current working directory, obtained in the native format as if by POSIX getcwd(). The signature with argument ec returns path() if an error occurs.

...

Rationale:

The lexical operation specifications leave some room for variation among implementations, but not as much as may be required for native formats; further relaxation would compromise the utility of the operations for portable, predictable path manipulation. Instead, we specify a usable but flexible mapping between the two formats and define each operation in terms of one (or, occasionally, both).

The second bullet item in the first note in [path.fmt.cvt], which says for POSIX- or Windows-based operating systems "There is no need to distinguish between native format and generic format in function arguments.", may not be true on Windows even if the other two bullet items are true.

US 75, CA 4; 27.10.8.4.1 [path.construct]: Extra flag in path constructors is needed
Status: Accept with modifications

See P0430R1 Section 2.2 for wording.

US 76, CA 5; 27.10.8.1 [path.generic]: root-name definition is over-specified
Status: Accept with modifications

See P0430R1 Section 2.3.1 for wording.

US 77, CA 6; 27.10.8.4.3 [path.append]: operator/ and other appends not useful if arg has root-name
Status: Accept with modifications

See P0430R1 Section 2.3.2 for wording.

US 78, CA 7; 27.10.15.1 [fs.op.absolute]: Member absolute() in 27.10.4.1 is overspecified for non-POSIX-like O/S
Status: Accept with modifications

See P0430R1 Section 2.4.1 for wording.

US 79, CA 8; Several: Some operation functions are overspecified for implementation-defined file types
Status: Accept with modifications

See P0430R1 Section 2.4.2 for wording.

NB comments submitted as editorial

There was concern that some of these might involve substantive changes, so the SG processed them as ordinary technical comments.

US 38; 27.10.4.13 [fs.def.symlink]:  Duplicates §17.3.16
Status: Accept

Project editor will make change.

US 39; 27.10.4.15 [fs.def.parent]: Remove note: Dot and dot-dot are not directories
Status: Accept

Project editor will make change.

US 41; 27.10.4.16 [fs.def.parent.other]: The term “parent directory” for a (non-directory) file is unusual
Status: Reject

Insufficient motivation for change. "parent directory" is the term we use to describe the containing directory; we're (already) following POSIX there, even though the POSIX definition is a bit weird.

US 42; 27.10.4.21 [fs.def.symlink]: Pathname resolution does not always resolve a symlink
Status: Reject

There is an apparent corner case contradiction between the POSIX definition and other places in the POSIX standard. The [fs.def.symlink] definition is identical to the POSIX 3.381 Symbolic Link definition () and the SG prefers to keep it that way.

US 47; 27.10.8.1 [path.generic]: “.” and “..” already match the name production
Status: Accept with modifications

Proposed resolution: that this is not editorial, but we know the fix. Davis Herring to supply updated proposed wording.

US 50;  27.10.8.3 [path.req]: path requirements ¶ 1.4 largely redundant with ¶ 1.3
Status: Reject

Beman to open an issue to expose this concern to additional experts. This is not a priority issue for shipping C++17.

Late comments from P0489R0

Quoting P0489R0, "These comments were not submitted in time to be registered as National Body Comments, but should be considered as possible issues against SC 22, N3151, ISO/IEC CD 14882."

Late 15; 27.10.8.4.11 ¶3.1: A “mismatched element” cannot be equal to an iterator

Late 16; 27.10.8.4.11 ¶3.3.1: lexically_relative("..\\foo") produces nonsense.

Late 17; 27.10.8.4.11 ¶3.3.2: Behavior not always appropriate

Late 18; 27.10.8.4.11 ¶4: Behavior wrong in case corresponding to comment Late17

Late 19; 27.10.8.5 ¶2: It is surprising that a path is a container of paths

Recommend NAD. See US 55, US 59.

Late 20; 27.10.11 ¶1: Anemic status structure

Late 21; 27.10.12: directory_entry is just a tivial wrapper for path

Late 22; 27.10.13 ¶6: directory_iterator cumbersome to assemble full path with iterator’s directory

Late 23; 27.10.14.1 ¶28: disable_recursion_pending() name is ugly implementation detail

Late 24; 27.10.15.1 ¶1: absolute() can produce nonsense result

Late 25; 27.10.15.4 ¶4.2: What attributes does copy_file() copy?

Late 26; 27.10.15.6 ¶5: create_directories() complexity assumes syscalls take constant time

Late 27; 27.10.15.7 ¶5: create_directory() specification prevents sensible security measures

Late 28; 27.10.15.10: create_symlink() might misbehave if to is a directory

Late 29; 27.10.15.13: Access to file ID is superior to equivalent()

Late 30; 27.10.15.13 ¶3: equivalent()'s s1==s2 check is ill-formed and could race

Late 31; 27.10.15.13 ¶5: Surprising that equivalent()'s error_code overload can throw

Late 32; 27.10.15.13 ¶5 : equivalent() should not reject special files outright

Late 33; 27.10.15.21: is_other() result surprising

Late 34; 27.10.15.25 ¶5: Could last_write_time() guarantee the error direction

Recommend submitting a paper that researches whether this is in fact possible. If it is possible, providing proposed wording would be helpful.

Late 35; 27.10.15.26: Why is there no way to read permissions?

Recommend NAD. They are available in file_status. If anyone thinks a separate function would be useful, they should submit an issue or a paper.

Late 36; 27.10.15.26: The permissions() error_code overload should be noexcept
Status: Accept

Change 27.10.15.26 [fs.op.permissions] and 27.10.6 Header <filesystem> synopsis [fs.filesystem.syn]:

void permissions(const path& p, perms prms, error_code& ec) noexcept;

Late 37; 27.10.15.26 ¶2:permissions() actions should be separate parameter

Matt Austern pointed out this issue and its fix for the TS, but it got dropped on the floor in the TS shipping rush and has never been fixed. We should probably fix it now or never.  Beman will propose wording, and ask the LWG/LEWG give it priority 1 in Kona.

Late 38; 27.10.15.26 ¶2: Unimplementable implication that permissions() is atomic

Late 39; 27.10.15.29 ¶3: Suprising relative() behavior for symlinks

Late 40; 27.10.15.31 ¶1: remove_all() unclear for symlink/

Late 41; 27.10.15.31 ¶3: Would be useful for remove_all() to report successful removal count on error

Late 42; 27.10.15.33 ¶1: resize_file() Postcondition missing argument
Status: Accept with modifications

Check the post-Issaquah working paper. This may have already been fixed as editorial.

Change 27.10.15.33 [fs.op.resize_file]:

Postcondition: file_size(p) == new_size.

Late 43; 27.10.15.33 ¶3: Add POSIX ftruncate() equivalent function

Recommend opening issue. Such a feature might be useful in 27.9 [file.streams] for C++2n.

Late 44; 27.10.15.38: system_complete() name inconsistent with similar functions in subclause

Late 45; 27.10.15.38 ¶6: Remove system_complete() unless it can be made reliable

Late 46; 27.10.15.40 ¶2: Question about weakly_canonical() Effects

Late 47; 27.10.15.40 ¶4: weakly_canonical() suggested caching is incorrect