NAME
    Input -- Identify the program's initial input file handle
SYNOPSIS
    file = Input()
    D0
    BPTR Input(void)
FUNCTION
    Input() is used to identify the initial input stream allocated when
    the program was initiated.  Never close the filehandle returned by
    Input!
RESULTS
    file - BCPL pointer to a file handle
SEE ALSO
    Output(), SelectInput()