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);