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3098. Misleading example for filesystem::path::filename()

Section: 31.12.6.5.9 [fs.path.decompose] Status: New Submitter: Jonathan Wakely Opened: 2018-04-06 Last modified: 2020-09-06

Priority: 3

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Discussion:

The example in [fs.path.decompose] p7 includes:

path("//host").filename();  // yields ""

This result isn't guaranteed, it depends whether the implementation interprets "//host" as a root-name or as a root-directory (with a redundant directory-separator) followed by the filename "host".

The example should make it clear that this interpretation is allowed.

Previous resolution [SUPERSEDED]:

This wording is relative to N4727.

1. Edit 31.12.6.5.9 [fs.path.decompose] as indicated:

   path filename() const;
   

   -6- Returns: relative_path().empty() ? path() : *--end().

   [Example:

   path("/foo/bar.txt").filename(); // yields "bar.txt"
   path("/foo/bar").filename();     // yields "bar"
   path("/foo/bar/").filename();    // yields ""
   path("/").filename();            // yields ""
   path("//host").filename();       // yields "" or "host"
   path(".").filename();            // yields "."
   path("..").filename();           // yields ".."
   

   — end example]

[2018-04-10, Jonathan comments and provides revised wording]

Based on the reflector discussion I'd like to change the P/R to Billy's suggestion of simply removing that line from the example.

[2018-06-18 after reflector discussion]

Priority set to 3

Proposed resolution:

This wording is relative to N4741.

1. Edit 31.12.6.5.9 [fs.path.decompose] as indicated:

   path filename() const;
   

   -6- Returns: relative_path().empty() ? path() : *--end().

   [Example:

   path("/foo/bar.txt").filename(); // yields "bar.txt"
   path("/foo/bar").filename();     // yields "bar"
   path("/foo/bar/").filename();    // yields ""
   path("/").filename();            // yields ""
   path("//host").filename();       // yields ""
   path(".").filename();            // yields "."
   path("..").filename();           // yields ".."
   

   — end example]