OpenEuphoria

Re: DOS undocumented feature

• Posted by Kat <gertie at PELL.NET> Jul 21, 2002
• 468 views

On 21 Jul 2002, at 12:15, Robert Craig wrote:

> 
> Ricardo Forno writes:
> > While trying to enhance your DUPFILE.EXW program
> > with some additional options, I discovered what seems
> > to be an undocumented feature of DOS under
> > Windows 98 SE. This happens only in a DOS window,
> > not when you restart in DOS mode.
> > As you know, . means the current directory, and .. means the parent
> > directory. But ... means the parent of the parent directory,
> > .... the parent of the parent of the parent, and so on.
> 
> That apparently doesn't work on XP. Only . and .. work.
> 
> > So, maybe the number of possible platforms should be increased.
> 
> I'm not sure what you mean. dupfile.exw works (more or less) on all
> platforms. Only "." and ".." are reported by the system calls that dir()
> uses. I guess "..." and "...." are supported artificially by the
> Win 98 command-line processor.

Which means you can write Eu code to artificially support it too, Ricardo. 
Same as adding a huge long path with create_directory().
 
> > Do you know why some files processed by DUPFILE.EXW when run
> > through ex raise a "Critical error" condition?
> 
> That's what DOS does when a DOS program tries to open a locked file.
> Not very helpful. It will help if you close all your Windows apps
> before scanning the whole drive with ex dupfile.exw.

Even less helpful, Rob. What about checking the file attributes before any 
operations on them, Ricardo?

Kat