[讨论]：为什么lisp程序中途退出后,不能恢复捕捉设置,如何修改？

wyihui

下面是一个在直线端点加画箭头的lisp,是这样的情况,若将命令完整执行完,结束后不会更改原来的捕捉设置,若中途按Esc退出,则退出后捕捉设置不能还原到操作前的状态。
请问如何修改?请高人将安全改好后的代码贴出来,让我学习一下,本菜鸟感激不尽.

这是我的lisp：

(defun C:JT (/ LNENT LNAME PCKPT EPT EPT1 EPT2 ANG1 DD PT2 PW)
  ;draws an arrowhead on the end of a line
  (setq XOSMODE (getvar "osmode"))
  (setvar "osmode" 512)
  ;;snap nearest
  (setq        LNENT (entsel "Pick near end of line") ;select end of line
        LNAME (car LNENT) ;extract entity name
        PCKPT (cadr LNENT) ;extract selection point
        EPT   (osnap PCKPT "endp") ;set endpt of selected line
        EPT1  (cdr (assoc 10 (entget LNAME))) ;extract start pt of line
        EPT2  (cdr (assoc 11 (entget LNAME)))
  ;extract other endpt of line
  ) ;_ end of setq
  (if (equal EPT EPT1) ;test desired endpt is same as start pnt
    (setq ANG1 (angle EPT1 EPT2)) ;if it is set variable for line angle
    (setq ANG1 (angle EPT2 EPT1))
  ;if not - line angle in other direction
  ) ;_ end of if
  (setq PT2 (polar EPT ANG1 350))
  ;set arrowhead length, based on current dimscale
  (setq PW 80) ;set arrowhead width
  (setvar "osmode" 0)
  (command "PLINE" EPT "W" "0" PW PT2 "") ;draw arrowhead
  (setvar "OSMODE" XOSMODE)
) ;_ end of defun

(princ
)

原地踏步

应定义一个错误函数，恢复原来的设置。

A332372

多段线宽度变了，你个沙雕沙雕沙雕沙雕沙雕