Function _isreservedname

Lib/ntpath.py:318–331

Return true if the filename is reserved by the system.

(name)

    return any(_isreservedname(name) for name in reversed(path.split(sep)))

def _isreservedname(name):
    """Return true if the filename is reserved by the system."""
    # Trailing dots and spaces are reserved.
    if name[-1:] in ('.', ' '):
        return name not in ('.', '..')
    # Wildcards, separators, colon, and pipe (*?"<>/\:|) are reserved.
    # ASCII control characters (0-31) are reserved.
    # Colon is reserved for file streams (e.g. "name:stream[:type]").
    if _reserved_chars.intersection(name):
        return True
    # DOS device names are reserved (e.g. "nul" or "nul .txt"). The rules
    # are complex and vary across Windows versions. On the side of
    # caution, return True for names that may not be reserved.
    return name.partition('.')[0].rstrip(' ').upper() in _reserved_names


# Expand paths beginning with '~' or '~user'.