Visual LISP, AutoLISP and General Customization

[#1]

I've got a subroutine that gets the centroid of a closed polygon (lwpoly).  It appears to fail if the polygon has any zero length line segments.  I've added a trap that catches the error and "highlights" the offending polygon, but it stops there and does not return to the main function that called the subroutine.  Is there a way to get back to the main function from the trap?

Here's the subroutine (original function by _gile (Autodesk LISP Forum 9-18-2006):

(defun return-centroid (lwpoly space / obj Region Centroid)
(setq *error* trap1)
(setq obj (vlax-ename->vla-object lwpoly))
(setq Region (vlax-invoke space 'addRegion (list obj)))
(setq Centroid (trans (vlax-get (car Region) 'Centroid) 1 0))
(vla-delete (car Region))
Centroid
)

(defun trap1 (errmsg)
(prompt "\nUnable to determine centroid of highlighted polygon")
(setq centroid nil)
(command "pedit" pe "w" 10 "")
(setq *error* temperr)
)

[#2]

The LISP (*error*) handler oncly cleans things up, it doesn't return to the program flow.  What I've done for invalid centroids is use the (vl-catch-all-apply...) and (vl-catch-all-error-p...) functions when getting the Centroid property, allowing me to check if getting the property threw an error or not while still continuing with the program flow.

[#3]

Thanks.  Looks like I'll have to add the vl-catch-all functions.