30 Input/output library [input.output]

30.10 File systems [filesystems]

30.10.7 Class path [fs.class.path]

30.10.7.4 path members [fs.path.member]

30.10.7.4.3 path appends [fs.path.append]

The append operations use operator/= to denote their semantic effect of appending preferred-separator when needed.
path& operator/=(const path& p);
Effects: If p.is_­absolute() || (p.has_­root_­name() && p.root_­name() != root_­name()), then operator=(p).
Otherwise, modifies *this as if by these steps:
  • If p.has_­root_­directory(), then removes any root directory and relative path from the generic format pathname.
    Otherwise, if !has_­root_­directory() && is_­absolute() is true or if has_­filename() is true, then appends path​::​preferred_­separator to the generic format pathname.
  • Then appends the native format pathname of p, omitting any root-name from its generic format pathname, to the native format pathname.
[Example
:
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:
// 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.
template <class Source> path& operator/=(const Source& source); template <class Source> path& append(const Source& source);
Effects: Equivalent to: return operator/=(path(source));
template <class InputIterator> path& append(InputIterator first, InputIterator last);
Effects: Equivalent to: return operator/=(path(first, last));