Arguments

curveEnt  (ename or vla-object) the COM object of any "curve" entity

Return

double;  the perimeter of the curve or NIL

Example

last entity is a CIRCLE with radius = 1.0 :
(setq ent (vlax-ename->vla-object (entlast)))  #<VLA-OBJECT IAcadCircle 000000004E8E3920>
(vlax-curve-getperimeter ent)  6.28318530717959

Remarks

this function is specific for BricsCAD, not available in AutoLISP !