When the decc$to_vms function evaluates a UNIX style path string,
    if it determines the first element to be a logical name, then:

    o  For rooted logicals or devices, it appends ":[000000]" to the
       logical name.

       For example, if log1 is a rooted logical ($DEFINE LOG1
       [DIR_NAME.]) then /log1/filename.ext translates to
       LOG1:[000000]FILENAME.EXT.

    o  For nonrooted logicals, it appends just a colon (:)  to the
       logical name.

       For example, if log2 is a nonrooted logical ($ DEFINE
       LOG2 [DIR_NAME]), then /log2/filename.ext translates to
       LOG2:FILENAME.EXT.

    o  If the first element is a search-list logical, the translation
       proceeds by evaluating the first element in the search list,
       and translating the path as previously described.

    The preceding three cases lead to predictable, expected results.

    In the case where the first element is a search list that
    consists of a mixture of rooted and nonrooted logicals,
    translating paths as described previously can lead to different
    behavior from that of older versions of OpenVMS (before OpenVMS
    Version 7.3-1):

    o  Before OpenVMS Version 7.3-1, regardless of the contents of
       the logical, the decc$to_vms function appended only a colon
       (:).  For search lists that consisted of a mixture of rooted
       and nonrooted logicals, this resulted in certain expected
       behaviors.

    o  For OpenVMS Version 7.3-1 and later, if the first element
       of the mixed search list is a rooted logical, then decc$to_
       vms appends ":[000000]" to the logical name, resulting in
       different behavior from that of OpenVMS releases prior to
       Version 7.3-1.

    DECC$NO_ROOTED_SEARCH_LISTS controls how the decc$to_vms function
    resolves search-list logicals and provides a means to restore the
    OpenVMS behavior prior to Version 7.3-1.

    With DECC$NO_ROOTED_SEARCH_LISTS enabled:

    o  If a logical is detected in a file specification, and it is
       a search list, then a colon (:)  is appended when forming the
       OpenVMS file specification.

    o  If it is not a search list, the behavior is the same as with
       DECC$NO_ROOTED_SEARCH_LISTS disabled.

    Enabling this feature logical provides the pre-Version 7.3-1
    behavior for search list logicals.

    With DECC$NO_ROOTED_SEARCH_LISTS disabled:

    o  If a logical is detected in a file specification, and it is
       a rooted logical (or a search list whose first element is a
       rooted logical), then ":[000000]" is appended when forming the
       OpenVMS file specification.

    o  If it is a nonrooted logical (or a search list whose first
       element is a nonrooted logical), then just a colon (:)  is
       appended.

    Disabling this feature logical provides the behavior for OpenVMS
    Version 7.3-1 and later.