VMS Help RTL Routines, LIB$, LIB$GETDVI  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The Get Device/Volume Information routine provides a simplified
    interface to the $GETDVI system service. It returns information
    about the primary and secondary device characteristics of an I/O
    device. The calling process need not have a channel assigned to
    the device about which it wants information.

    Format

      LIB$GETDVI  item-code [,channel] [,device-name]

                  [,longword-integer-value] [,resultant-string]

                  [,resultant-length]

1 - Returns

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

2 - Arguments

 item-code

    OpenVMS usage:longword_signed
    type:         longword (signed)
    access:       read only
    mechanism:    by reference

    Code specifying the item of information you are requesting. The
    item-code argument is the address of a signed longword containing
    the item code. All valid $GETDVI item codes whose names begin
    with DVI$_ are accepted.

 channel

    OpenVMS usage:channel
    type:         word (unsigned)
    access:       read only
    mechanism:    by reference

    OpenVMS I/O channel assigned to the device for which LIB$GETDVI
    returns information. The channel argument is the address of an
    unsigned word containing the channel specification. If channel is
    not specified, device-name is used instead. You must specify
    either channel or device-name, but not both. If neither is
    specified, the error status SS$_IVDEVNAM is returned.

 device-name

    OpenVMS usage:device_name
    type:         character string
    access:       read only
    mechanism:    by descriptor

    Name of the device for which LIB$GETDVI returns information.
    The device-name argument is the address of a descriptor pointing
    to the device name string. If this string contains a colon, the
    colon and the characters that follow it are ignored.

    The device-name may be either a physical device name or a logical
    name. If the first character in the string is an underscore
    character (_),  the name is considered a physical device name.
    Otherwise, the name is considered a logical name, and logical
    name translation is performed until either a physical device name
    is found or the system default number of translations has been
    performed.

    If device-name is not specified, channel is used instead. You
    must specify either channel or device-name, but not both. If
    neither is specified, the error status SS$_IVDEVNAM is returned.
    The device name must not be longer than 255 characters.

 longword-integer-value

    OpenVMS usage:longword_signed
    type:         longword (signed)
    access:       write only
    mechanism:    by reference

    Numeric value of the information requested. The longword-integer-
    value argument is the address of a signed longword containing the
    numeric value. If an item is listed as only returning a string
    value, this argument is ignored.

 resultant-string

    OpenVMS usage:char_string
    type:         character string
    access:       write only
    mechanism:    by descriptor

    String representation of the information requested. The
    resultant-string argument is the address of a descriptor pointing
    to this information. If resultant-string is not specified and if
    the value returned has only a string representation, the error
    status LIB$_INVARG is returned.

 resultant-length

    OpenVMS usage:word_unsigned
    type:         word (unsigned)
    access:       write only
    mechanism:    by reference

    Number of significant characters written to resultant-string by
    LIB$GETDVI. The resultant-length argument is the address of an
    unsigned word containing this length.