error-handling - 第一次错误后处理DCL ON ERROR Action ？

Question

OpenVMS DCL命令HELP ON EXAMPLE显示:

ON

Examples

   1.$ ON SEVERE_ERROR THEN CONTINUE

     A command procedure that contains this statement continues
     to execute normally when a warning or error occurs during
     execution. When a severe error occurs, the ON statement signals
     the procedure to execute the next statement anyway. Once
     the statement has been executed as a result of the severe
     error condition, the default action (ON ERROR THEN EXIT) is
     reinstated.

根据帮助，如果 [-]x.for和 [-]y.for都不存在，那么将不执行最后两行:

$ on error then $ continue
$ rename [-]x.for []
$ rename [-]y.for []
$ type *.for

是否可以像在第一行中那样在脚本的每一行之间不放置 ON ERROR语句来设置 ON ERROR处理？

Answer 1

如果发生ON ERROR，则必须重新建立它。看起来像你
不知道是否存在任何文件。所以ON ERROR需要是
在第一个失败的命令后重新建立。

您可以在子例程中执行此操作，例如:

$ on error then $ gosub on_error
$ rename [-]x.for []
$ rename [-]y.for []
$ on error then $ exit
$ type *.for
$ exit
$
$ on_error:
$ on error then $ gosub on_error
$ return

另外，您可以通过禁用错误检查(SET
中午):

$ set noon
$ rename [-]x.for []
$ rename [-]y.for []
$ set on
$ type *.for

或仅针对严重错误建立错误处理(ON SEVERE_ERROR):

$ on severe_error then $ exit
$ rename [-]x.for []
$ rename [-]y.for []
$ on error then $ exit
$ type *.for