context

    OpenVMS usage:context
    type:         longword (unsigned)
    access:       modify
    mechanism:    by reference
    User context information to be passed to other user routines. The
    context argument is the address of a longword that contains user
    context information.

    You should specify the value of this argument as 0 in the first
    of a sequence of calls to MAIL routines. In following calls, you
    should specify the user context value returned by the previous
    routine.

 in_item_list

    OpenVMS usage:itmlst_3
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Item list specifying options for the routine. This routine does
    not use the in_item_list argument.

 out_item_list

    OpenVMS usage:itmlst_3
    type:         longword
    access:       write only
    mechanism:    by reference
    Item list specifying the information you want the routine to
    return. The out_item_list argument is the address of a list of
    item descriptors, each of which describes an item of information.
    The list of item descriptors is terminated by longword value of
    0.