TheSwamp

Code Red => AutoLISP (Vanilla / Visual) => Topic started by: highflyingbird on June 27, 2012, 09:03:08 AM

Title: A safearray is a kind of reference?
Post by: highflyingbird on June 27, 2012, 09:03:08 AM

A safearray is a kind of  reference?
It means ,when we copy a safearray , if  the element in origin has been changed,the copy one changed also.
Let's see this test:

Code - Auto/Visual Lisp: [Select]

1. (defun c:test (/ lst oArray rArray value1 value2 List->SafeArray)
2.   (defun List->SafeArray (L DataType)
3.     (vlax-safearray-fill
4.       (vlax-make-safearray DataType
5.         (cons 0 (1- (length L)))
6.       )
7.       L
8.     )
9.   )
10.   (setq lst '(1 2 3 4 5 6))
11.   (setq oArray (list->safearray lst vlax-vbInteger))    ;Make a new safearray
12.   (setq rArray oArray)                                  ;->just a kind of reference
13.  
14.   (vlax-safearray-put-element oArray 0 7)               ;Change the first element to a new value
15.  
16.   (setq value1 (vlax-safearray-get-element oArray 0))   ;Get the 1st element value from origin
17.   (setq value2 (vlax-safearray-get-element rArray 0))   ;The copy one has been changed at the same time!!!
18.   (= value1 value2)                                     ;they are equal. --> T
19.  
20.   (vlax-safearray-put-element rArray 5 8)               ;do another test
21.  
22.   (setq value1 (vlax-safearray-get-element rArray 5))   ;Get the 1st element value from the copy
23.   (setq value2 (vlax-safearray-get-element oArray 5))   ;The origin has been changed at the same time!!!
24.   (= value1 value2)                                     ;they are equal.  --> T
25.  
26.   (princ)
27. )
28.  

Title: Re: A safearray is a kind of reference?
Post by: irneb on June 27, 2012, 09:43:02 AM

It does seem so yes. I'm guessing it's implemented along the same lines as a selection set (e.g. using ssadd / ssdel modifies the original).