Hello to everybody! ------------------------- Sorry for disturbing you all with the question that may not be very clever! In some code that one can see in this NG and in others here, for example, the answer of L.E. (Hi, Luis! ;^) from: * autodesk.autocad.2000general * 05/05/2001 by Albert Giuliano * Re: a button for toggling vport locking?? I see the next object realesing method at the end of a function: (if (vlax-object-released-p obj) (setq obj nil) (vlax-release-object obj) ) and some others. My questions: -------------- 1. Why do set 'obj' to 'nil'? Is it nesessery or it's a "dump" operation? 2. If *there are no* 'obj', you'll get an error! So, why do not examine the existense of 'obj' first: (if obj (if (not (vlax-object-released-p obj)) (vlax-release-objectobj) ) ) or examine that it IS and it IS a VLA-object and then release it and set it to 'nil': (if (= (type obj) 'VLA-OBJECT) (if (vlax-object-released-p obj) (setq obj nil) (progn (vlax-release-object obj) (setq obj nil) ) ; - 'progn' ) ; - 'if obj NOT RELEASED YET' ) ; - 'if obj EXISTS' What do you think about that? Thank you all for your time and help and ideas!
See below. The above will not work, because vlax-release-object requires a valid vla-object, but the expression before it sets the obj variable to nil. See above. As to the remainder, you should not conditionally test an object to see if you need to release it. You should write your code to explicitly release it if you created it, and do that only once. If the object is not valid, that means there is an error somewhere else in the code, and allowing (vlax-release-object) to _fail_ will serve to indicate that. By testing the validity of the vla-object and not releasing it if it isn't valid, you may be concealing another error in the code. Try to avoid writing code that hides errors.
Tony, Luis' code _does_ work. I'm sure you simply missed that he is setting the variable to nil if it has already been released (then statement), and releases it if it was not released (else statement). However, Luis is not setting the variable to nil in the else clause, so it isn't really complete either. We all appreciate you wise comments about avoiding concealing errors. -- R. Robert Bell "Tony Tanzillo" <tony.tanzillo/at/caddzone/dot/com> wrote in message See below. The above will not work, because vlax-release-object requires a valid vla-object, but the expression before it sets the obj variable to nil. See above. As to the remainder, you should not conditionally test an object to see if you need to release it. You should write your code to explicitly release it if you created it, and do that only once. If the object is not valid, that means there is an error somewhere else in the code, and allowing (vlax-release-object) to _fail_ will serve to indicate that. By testing the validity of the vla-object and not releasing it if it isn't valid, you may be concealing another error in the code. Try to avoid writing code that hides errors.
Hi Robert! -------------- I think so and I was very astonished about this... My comments STILL half-wise for a years... Searching this NG I found a very interesting discussion: "vlax-release-object...cont'd" started by Cliff Middleton Sep/27/01 with participation of you Robert & John Uhden & Tony Tanzillo & Frank Oquendo & Owen Wengerd & Luis Esquivel & others... It's cool! And many others about that. So I made a conclusion: ============================ 1. Not to set VLA-objects to NIL *before* releasing them. 2. Release them and NOT to set them to NIL after if they are locals. 3. Don't use globals like ACAD and DOC ("no globals - no problem...") 4. Release VLA-objects ALWAYS if they were: a) external (applications like Excel) - not tryed yet... b) created with (vla-add-... ) c) created with (vlax-ename->vla-object ...) d) selection sets (it seems to me that I had some problems wich were gone after releasing SSs) Is it true? Thank you all!
Your summary looks good to me. I can't think of anything else at the moment. -- R. Robert Bell Hi Robert! -------------- .... Searching this NG I found a very interesting discussion: "vlax-release-object...cont'd" started by Cliff Middleton Sep/27/01 with participation of you Robert & John Uhden & Tony Tanzillo & Frank Oquendo & Owen Wengerd & Luis Esquivel & others... It's cool! And many others about that. So I made a conclusion: ============================ 1. Not to set VLA-objects to NIL *before* releasing them. 2. Release them and NOT to set them to NIL after if they are locals. 3. Don't use globals like ACAD and DOC ("no globals - no problem...") 4. Release VLA-objects ALWAYS if they were: a) external (applications like Excel) - not tryed yet... b) created with (vla-add-... ) c) created with (vlax-ename->vla-object ...) d) selection sets (it seems to me that I had some problems wich were gone after releasing SSs) Is it true?
Humble question: Why should we explicitly release VLA-objects when the symbols are local to the function? Aren't they released and cleaned up automatically when the function ends or the symbol goes out of scope? e.g. (given e = ename) (defun foo (/ e Obj) (if (setq e (car (entsel "\nSelect an object: "))) (progn (setq Obj (vlax-ename->vla-object e)) (..do something interesting here..) (vlax-release-object obj) ;<-- do I need this? If so, why? ) ) (princ) ) Matt
Hi Luis! ----------- From: fishspawned <> Newsgroups: autodesk.autocad.2000general Subject: a button for toggling vport locking?? Date: Thu, 3 May 2001 06:39:26 -0700 Albert Giuliano said that was your code... hm... a piece of self-criticism... And how do you do it all without releasing them??? Thank your for your good (and not good) ideas! ; )
Hello Matt! --------------- You have to read a great and very didactic discussions about that in this NG! For example: vlax-release-object...cont'd Posted by: Middleton, Cliff Date: Sep/27/01 - 05:15 (GMT) In this NG! and Vlax-release-object help neede in VLisp (8 replies) Posted by: McManamy, Rodney Date: Jul/26/00 - 21:20 (GMT) Search the Web-side of the Autodesk NG: http://discussion.autodesk.com/forum.jspa?forumID=130 something like "release" or "releasing" as I did! You'll be satisfied! ; )
Glad to hear you Luis! ------------------------- Hm! I use them local! But it seems to me that I got reactor crashes before I've heard about VLA-objects releasing ... I will try! Thank for good NEWS!
Hi Matt! --------- See my reply to Luis: before he sad he don't use releasing now I WAS certain in fact that NOT releasing Objects cause AutoCAD closes unexpectedly and such a problems!.. I HAD permanent errors and AutoCAD crashes when DIDN'T (vlax-release-object obj) in Reactors. Maybe it's a problem only in reactors? Maybe it was a problem only IN MY reactors?.. So I was surprised a lot by Luis post... Now I would know: HOW DOES HE LIVES without releasinig VLA-objects in his code (and reactors???)... My English don't allow me to paraphrase the long discussions in here about that. I *would* release them in my code, because of possible errors and AutoCAD crashes (in my reactors) - the only place when I try to use the new VLA possibilities. In my other code I rarely use VLA-functions & VLA-objects yet. Many happy LISP to you! ; )
