zone-id

    OpenVMS usage:identifier
    type:         longword (unsigned)
    access:       write only
    mechanism:    by reference

    Zone identifier. The zone-id argument is the address of a
    longword that receives the identifier of the newly created zone.

 user-argument

    OpenVMS usage:user_arg
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference

    User argument. The user-argument argument is the address of an
    unsigned longword containing the user argument. LIB$CREATE_USER_
    VM_ZONE copies the value of user-argument and supplies the value
    to all user procedures invoked.

 user-allocation-procedure

    OpenVMS usage:procedure
    type:         procedure value
    access:       function call (before return)
    mechanism:    by value

    User allocation routine.

 user-deallocation-procedure

    OpenVMS usage:procedure
    type:         procedure value
    access:       function call (before return)
    mechanism:    by value

    User deallocation routine.

 user-reset-procedure

    OpenVMS usage:procedure
    type:         procedure value
    access:       function call (before return)
    mechanism:    by value

    User routine invoked each time LIB$RESET_VM_ZONE is called for
    the zone.

 user-delete-procedure

    OpenVMS usage:procedure
    type:         procedure value
    access:       function call (before return)
    mechanism:    by value

    User routine invoked when LIB$DELETE_VM_ZONE is called for the
    zone.

 zone-name

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

    Name to be associated with the zone being created. The optional
    zone-name argument is the address of a descriptor pointing to the
    zone name. If zone-name is not specified, the zone will not have
    an associated name.