VMS Help CLI Routines, CLI$PRESENT, Argument  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 entity_desc

    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by descriptor
    Character string containing the label (or name if no label is
    defined) of the entity. The entity_desc argument is the address
    of a string descriptor that points to an entity that may appear
    on a command line. An entity can be expressed as one of the
    following:

    o  A parameter, qualifier, or keyword name or label

    o  A keyword path

    A keyword path is used to reference keywords that are accepted
    by parameters, qualifiers, or other keywords. A keyword path
    contains a list of entity names separated by periods. See the
    description of the entity_desc argument in the CLI$GET_VALUE
    routine for more information about specifying keyword paths as
    arguments for CLI routines.

    The entity_desc argument can contain parameter, qualifier, or
    keyword names, or can contain labels that were assigned with
    the LABEL clause in the command definition file. If the LABEL
    clause was used to assign a label to a qualifier, parameter, or
    keyword, you must specify the label in the entity_desc argument.
    Otherwise, you must use the actual name of the qualifier,
    parameter, or keyword.

    If the entity_desc argument does not exist in the command table,
    CLI$PRESENT signals a syntax error (by means of the signaling
    mechanism described in the OpenVMS Programming Concepts Manual).