2761. directory_entry comparisons are members

Section: 30.11.11.3 [fs.dir.entry.obs] Status: NAD Submitter: Ville Voutilainen Opened: 2016-08-03 Last modified: 2017-03-19

Priority: 2

View all other issues in [fs.dir.entry.obs].

View all issues with NAD status.

Discussion:

The comparison operators for directory_entry are member functions (30.11.11.3 [fs.dir.entry.obs]).

That means that a directory_entry can be compared with a path, but a path cannot be compared with a directory_entry, because the left-hand side is not subject to conversions. This seems unfortunate.

Note that the comparisons for path are non-members (30.11.7.6 [fs.path.nonmember]).

The meta-p/r is to turn the directory_entry comparisons into non-member functions.

[2016-08 Chicago]

Wed PM: Priority 2

[2016-10-05 Ville provides concrete wording]

[2016-10 Telecon]

This (comparing a path with a directory_entry) works today w/o any changes. Closing as NAD.

Proposed resolution:

This wording is relative to N4606.

  1. In 30.11.11 [fs.class.directory_entry] synopsis, edit as follows:

    namespace std::filesystem {
    class directory_entry {
    public:
      […]
      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
    };
    
    bool operator< (const directory_entry& lhs, const directory_entry& rhs) noexcept;
    bool operator==(const directory_entry& lhs, const directory_entry& rhs) noexcept;
    bool operator!=(const directory_entry& lhs, const directory_entry& rhs) noexcept;
    bool operator<=(const directory_entry& lhs, const directory_entry& rhs) noexcept;
    bool operator> (const directory_entry& lhs, const directory_entry& rhs) noexcept;
    bool operator>=(const directory_entry& lhs, const directory_entry& rhs) noexcept;
    
    }
    
  2. In 30.11.11.3 [fs.dir.entry.obs]/6-11, edit as follows:

    bool operator==(const directory_entry& lhs, const directory_entry& rhs) const noexcept;
    

    -6- Returns: pathobjectlhs.path() == rhs.pathobjectpath().

    bool operator!=(const directory_entry& lhs, const directory_entry& rhs) const noexcept;
    

    -7- Returns:: pathobjectlhs.path() != rhs.pathobjectpath().

    bool operator< (const directory_entry& lhs, const directory_entry& rhs) const noexcept;
    

    -8- Returns:: pathobjectlhs.path() < rhs.pathobjectpath().

    bool operator<<=(const directory_entry& lhs, const directory_entry& rhs) const noexcept;
    

    -9- Returns:: pathobjectlhs.path() <= rhs.pathobjectpath().

    bool operator> (const directory_entry& lhs, const directory_entry& rhs) const noexcept;
    

    -10- Returns:: pathobjectlhs.path() > rhs.pathobjectpath().

    bool operator>=(const directory_entry& lhs, const directory_entry& rhs) const noexcept;
    

    -11- Returns:: pathobjectlhs.path() >= rhs.pathobjectpath().