From 65aa6ae71a4d33401f96ff2e5d91e349eb92706a Mon Sep 17 00:00:00 2001
From: Eric Fiselier "/" has a filename of "/".
*this = parent_path(), except that if parent_path() == root_path(), clear().
+ Effects: *this = parent_path(), except that if parent_path() == root_name(), clear().
Returns: *this.