Function has_fileno

invoke/util.py:73–94

Cleanly determine whether ``stream`` has a useful ``.fileno()``. .. note:: This function helps determine if a given file-like object can be used with various terminal-oriented modules and functions such as `select`, `termios`, and `tty`. For most of those, a fileno

(stream: IO)

def has_fileno(stream: IO) -> bool:
    """
    Cleanly determine whether ``stream`` has a useful ``.fileno()``.

    .. note::
        This function helps determine if a given file-like object can be used
        with various terminal-oriented modules and functions such as `select`,
        `termios`, and `tty`. For most of those, a fileno is all that is
        required; they'll function even if ``stream.isatty()`` is ``False``.

    :param stream: A file-like object.

    :returns:
        ``True`` if ``stream.fileno()`` returns an integer, ``False`` otherwise
        (this includes when ``stream`` lacks a ``fileno`` method).

    .. versionadded:: 1.0
    """
    try:
        return isinstance(stream.fileno(), int)
    except (AttributeError, io.UnsupportedOperation):
        return False


def isatty(stream: IO) -> Union[bool, Any]: