Change system variable, offset, change system variable back
Accepted solution
@Anonymous wrote:
....
I'd like to write a routine called BUFFER that will change OFFSETGAPTYPE to 1, allow me to run the OFFSET command, then change OFFSETGAPTYPE back to 0. ....
What you need is to allow for User input to complete the OFFSET command, before going on to re-set the System Variable. This is done by checking the CMDACTIVE System Variable:
(defun c:buffer()
(setvar "offsetgaptype" 1)
(command "offset")
(while (> (getvar 'cmdactive) 0) (command pause))
(setvar "offsetgaptype" 0)
(princ)
)
Kent Cooper, AIA 
@Anonymous wrote:
.... I'm not sure you would need cmdactive part as it worked without it.
Really? It didn't for me:
Command: BUFFER
; error: Unknown (command-s) failure.
Help for (command-s) says you need to supply everything it will need for a completed command, to quote:
"The command that is being executed must be started and completed in the same command-s function."
That would explain the failure, but if you're not getting a failure, I'm intrigued -- how can that be? I'm in Acad2016 where I am at the moment, but that quote is still there in the 2018 AutoLisp Reference, so it doesn't seem like it can be a version-related difference.
Kent Cooper, AIA
@john.uhden wrote:
I think this is a slight improvement on @Ranjit_Singh's offering:
....... I think you needed the cmdactive part anyway.
I don't understand. Try the below code on your system.
(defun c:buffer() (setvar "offsetgaptype" 1) (command-s "offset") (setvar "offsetgaptype" 0) (princ) )
Does it not allow you to do everything within the command and then exit and still reset the variable? It does at my end.
(defun c:somefunc ( / ) (command-s "._offset") (setvar 'offsetgaptype 2) (command-s "._offset") (setvar 'offsetgaptype 1) (command-s "._offset") (setvar 'offsetgaptype 0) )
I agree that adding *error* trap is a good habit but it is certainly not needed in the context of this problem. Am I missing something?
@Anonymous wrote:
If you use the script that @Ranjit_Singh posted (copied below) then it works as described and it doesn't contain the cmdactive line. I'm currently working in AutoCAD 2018. ....
That's what I used, and I got the error I posted earlier.
Kent Cooper, AIA
@Ranjit_Singh wrote:
.... Does it not allow you to do everything within the command and then exit and still reset the variable? It does at my end
.... adding *error* trap is a good habit but it is certainly not needed in the context of this problem. Am I missing something?
It doesn't for me. I've now tried it on two different Acad2106 installations, one on a Windows 7 computer and one Windows 10. Could it be a version difference? If so, Help for 2018 needs to be modified to no longer say what I quoted before.
As for the *error* handler, what I think you are missing is that someone might start the command and ESCape out of it in mid-command, in which case surely the System Variable would not be reset. But I can't confirm that, since I can't run the command at all.
Kent Cooper, AIA
Kent1Cooper wrote:................As for the *error* handler, what I think you are missing is that someone might start the command and ESCape ...........
I did that in the previous post (post #8 first video). The video shows how the variable resets after finishing the command, as well as, when the command is simply cancelled. Here I present it again.
Maybe post a screencast of the error you are encountering.
Ranjit.Singh wrote.... Maybe post a screencast of the error you are encountering.
I'm not set up to do a screencast here, but it wouldn't reveal anything except what I showed in Post 7 -- I type in the command name and immediately get the error.
There must be some new capability and/or restorative feature in 2018, if that's what you're using. [I haven't been able to get my 2018 to run yet -- a checking-license problem, though it doesn't hang up until the third time it says it's checking, which also started happening in 2017 that was working before -- I guess it's time to buckle down and straighten that out.] Do you still have an older version around to try it on, for comparison? And it makes me wonder -- what if you write a routine that changes some System Variable and does not include setting it back? If you run the routine [with or without cancelling mid-way], does the System Variable get re-set anyway?
OR: Do you have your AutoCAD set up to operate with some special all-purpose restore-everything *error* handler in place of AutoCAD's own? Or have you loaded some routine that includes an *error* handler that does something like that, but is not localized, so that AutoCAD's own is not restored as it should be? Either would certainly be possible, and would explain the whole situation.
Kent Cooper, AIA
@Ranjit_Singh wrote:
.... I also find it very convenient for you to say “I'm not set up to do a screencast here, but it wouldn't reveal anything ....” and kind of hint that I have customized the system. What do I gain from doing that? How long does it take to do a screencast? Plus if someone is making a claim that Autodesk needs to correct their hep documents I believe they should provide a little bit more matter than just a statement ; error: Unknown (command-s) failure. Pretty easy to type that. An expert elite member needs to take a little more effort. Don’t you think so? Maybe you can take a screenshot. ....
You misunderstood. The question about whether you have customized your system had nothing whatever to do with screencasting. It was about whether you might have built in something that does what an *error* handler would do [specifically, changes back a System Variable value], without your having included an *error* handler in the routine.
I didn't type in the error message, as easy as that would be -- I copied/pasted it out of the command history. If you really think a screenshot could possibly reveal anything more about it, I'll put in that little bit more effort -- here you go, including the pasting in of the command definition itself. A screencast could not reveal anything more -- there would be nothing at all to see beyond this.
What immediately precedes that is the drawing of a rectangle, to be sure there would be something in the drawing to use the command on, if it had worked. That was the only thing I did in the drawing before what you see.
Kent Cooper, AIA