VMS Help System Services, $MTACCESS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Allows installations to provide their own routine to interpret
    and output the accessibility field in the VOL1 and HDR1 labels of
    an ANSI labeled magnetic tape.

    Format

      SYS$MTACCESS  lblnam ,[uic] ,[std_version] ,[access_char]

                    ,[access_spec] ,type

    C Prototype

      int sys$mtaccess  ( unsigned int *lblnam, unsigned int uic,

                        unsigned int std_version, unsigned int

                        access_char, unsigned int access_spec,

                        unsigned int type);

1 - Arguments

 lblnam

    OpenVMS usage:address
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    ANSI label to be processed. The lblnam argument is the address
    of a longword containing the label. On input, the label passed
    is either the VOL1 or HDR1 label read from the magnetic tape; on
    output of labels, the value of this field is 0. The type of label
    passed is determined by type.

 uic

    OpenVMS usage:uic
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    UIC of the user performing the operation. The uic argument is a
    longword containing the UIC.

 std_version

    OpenVMS usage:longword_unsigned
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Decimal equivalent of the ANSI standard version read from the
    VOL1 label. The std_version argument is a longword containing the
    standard version number.

 access_char

    OpenVMS usage:longword_unsigned
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Accessibility character specified by the user. The access_char
    argument is a byte containing the accessibility character used
    for the output of labels.

 access_spec

    OpenVMS usage:longword_unsigned
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Value specifying whether the accessibility character passed in
    access_char was specified by the user.

    The access_spec argument is a byte containing one of the
    following values:

    Value            Meaning

    MTA$K_           Yes
    CHARVALID
    MTA$K_NOCHAR     No

    This argument is used only for the output of labels.

 type

    OpenVMS usage:longword_unsigned
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Type of accessibility field to process.

    The type argument is a byte containing one of the following
    values:

    Value            Meaning

    MTA$K_INVOL1     Input a VOL1 label
    MTA$K_INHDR1     Input a HDR1 label
    MTA$K_OUTVOL1    Output a VOL1 label
    MTA$K_OUTHDR1    Output a HDR1 label