Specifying a NULL object.

[wizman]

here's what i tried se7en:

 

 

(setq acsp (vla-get-modelspace (vla-get-activedocument
       (vlax-get-acad-object)
       )))
;=>
;#<VLA-OBJECT IAcadModelSpace2 133ba2f4> 



(setq mtx (vlax-invoke
	     acsp 'AddMText '(1. 1. 0.) 0.0 "My_text")
       )
;=>
;#<VLA-OBJECT IAcadMText 13099764>



(vlax-invoke
   acsp
   'Addleader
   (apply 'append (list '(0. 0. 0.) '(1. 1. 0.)))
   mtx
   acLineWithArrow
) ;_ vlax-invoke
;=>
;#<VLA-OBJECT IAcadLeader 131a74e4>  ;;; ok







;;;now releasing mtx object





(vlax-release-object mtx)
;=>
;0


;;;inspecting mtx
;=>
;#<VLA-OBJECT 00000000> ;null object




;;;try again with a null object

(vlax-invoke
   acsp
   'Addleader
   (apply 'append (list '(0. 0. 0.) '(1. 1. 0.)))
   mtx
   acLineWithArrow
) ;_ vlax-invoke
;=>
;; error: null interface pointer: #<VLA-OBJECT 00000000>

[VovKa]

Se7en, i'd rather say that vlax-vbNull is not a null or nil, it's just a 'global' variable that is equal to 1