The help info is actually correct; I have no idea why they have different names for this constant in VBA and Lisp. Autodesk works in mysterious ways sometimes.
If you want to use the LDD constant names in Lisp (which you should - it makes your code more readable, and slightly more-likely to continue working in future versions of Autocad), you have to explicitly link the type library as follows:
(vl-load-com)
; import the Land type library
; this should only be done once, so first check to see if a
; constant defined by the type library already exists...
(if (null vll-kCurve)
(vlax-import-type-library
:tlb-filename "landauto.tlb"
:methods-prefix "vll-"
:properties-prefix "vll-"
:constants-prefix "vll-"
) ;_ vlax-import-type-library
) ;_ if
(defun c:testfunc ()
(setq acadObj (vlax-get-acad-object)
aeccApp (vla-getInterfaceObject acadObj "Aecc.Application")
aeccProj (vll-get-activeProject aeccApp)
cogoPoints (vll-get-cogoPoints aeccProj)
aeccPref (vll-get-preferences aeccProj)
alignPref (vll-get-profile aeccPref)
egLayer (vll-getString alignPref vll-kEgLayer)
) ; setq
) ;_ defun
This has the advantage that the LDD commands are now registered in the Lisp editor, so (after you run the
if statement above) the editor will highlight them. This makes it easy to tell if you spelled something wrong, or are trying to use a nonexistent constant name, etc. The resulting Lisp also runs faster, although most of the time this isn't noticeable.
If you want, you can define different prefixes for methods, properties, and constants, although I haven't found any use for this. I just prefix everything "vll-" because it's like "vla-" except with an "L" for "Land".