context

    OpenVMS usage:context
    type:         longword (unsigned)
    access:       modify
    mechanism:    by reference
    Message context information to be passed to message routines.
    The context argument is the address of a longword that contains
    message context information returned by MAIL$MESSAGE_BEGIN.

 in_item_list

    OpenVMS usage:itmlst_3
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Item list specifying options for the routine. The in_item_list
    argument is the address of a list of item descriptors, each of
    which specifies an option and provides the information needed to
    perform the operation.

    The item list is terminated by longword value of 0.