Function open

Lib/dbm/dumb.py:293–319

Open the database file, filename, and return corresponding object. The flag argument, used to control how the database is opened in the other DBM implementations, supports only the semantics of 'c' and 'n' values. Other values will default to the semantics of 'c' value: the databas

(file, flag='c', mode=0o666)

def open(file, flag='c', mode=0o666):
    """Open the database file, filename, and return corresponding object.

    The flag argument, used to control how the database is opened in the
    other DBM implementations, supports only the semantics of 'c' and 'n'
    values.  Other values will default to the semantics of 'c' value:
    the database will always opened for update and will be created if it
    does not exist.

    The optional mode argument is the UNIX mode of the file, used only when
    the database has to be created.  It defaults to octal code 0o666 (and
    will be modified by the prevailing umask).

    """

    # Modify mode depending on the umask
    try:
        um = _os.umask(0)
        _os.umask(um)
    except AttributeError:
        pass
    else:
        # Turn off any bits that are set in the umask
        mode = mode & (~um)
    if flag not in ('r', 'w', 'c', 'n'):
        raise ValueError("Flag must be one of 'r', 'w', 'c', or 'n'")
    return _Database(file, mode, flag=flag)