Specifies the display format for either date values, time values,
    or both.

    You must specify a numeric argument with the DATE and TIME
    portions of the SET DATE FORMAT statement. This numeric argument
    is the same as the numeric portion of certain OpenVMS Run-Time
    Library formats. The formats are documented in the OpenVMS run-
    time library documentation. (This statement only accepts numbers
    that reference OpenVMS format date and time logical names; it
    does not support the ANSI/ISO date and time data types.)

    The SET DATE FORMAT DATE and SET DATE FORMAT TIME statements
    change only the output for the date or time formats. If you want
    to change the input format, use the logical name LIB$DT_INPUT_
    FORMAT. You must run the command procedure SYS$MANAGER:LIB$DT_
    STARTUP.COM before using any of the run-time library date-time
    routines for input or output formats other than the default. The
    LIB$DT_STARTUP.COM procedure also defines spellings for date and
    time elements in languages other than English. See the OpenVMS
    run-time library documentation for more information on LIB$DT_
    INPUT_FORMAT.