efn

    OpenVMS usage:ef_number
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Number of the event flag that is set when the service completes.
    If this argument is omitted, event flag 0 is used.

 flags

    OpenVMS usage:mask_longword
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    Flags specifying options for the service. The flags argument is
    a longword bit mask in which each bit corresponds to an option
    flag. The $DDTMDEF macro defines symbolic names for the option
    flag listed in $FORGET_RM Option Flag. All undefined bits must be
    0. If this argument is omitted, no flags are used.

    Table SYS-18 $FORGET_RM Option Flag

    Flag Name      Description

    DDTM$M_SYNC    Specifies successful synchronous completion by
                   returning SS$_SYNCH. When SS$_SYNCH is returned,
                   the AST routine is not called, the event flag is
                   not set, and the I/O status block is not filled
                   in.

 iosb

    OpenVMS usage:io_status_block
    type:         quadword (unsigned)
    access:       write only
    mechanism:    by reference
    The I/O status block in which the completion status of the
    service is returned as a condition value.

    Refer to the VSI OpenVMS System Services Reference Manual to view
    the I/O status block diagram.

 astadr

    OpenVMS usage:ast_procedure
    type:         procedure entry mask
    access:       call without stack unwinding
    mechanism:    by reference
    The AST routine executed when the service completes, if SS$_
    NORMAL is returned in R0. The astadr argument is the address of
    the entry mask of this routine. The routine is executed in the
    same access mode as that of the caller of the $FORGET_RM service.

 astprm

    OpenVMS usage:user_arg
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    The AST parameter that is passed to the AST routine specified by
    the astadr argument.

 rm_id

    OpenVMS usage:identifier
    type:         longword (unsigned)
    access:       read only
    mechanism:    by value
    The identifier of the RMI to be deleted from the calling process.