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Re: [Patch] unlink

At 11:36 PM 10/30/2004 -0400, Christopher Faylor wrote:
>On Sat, Oct 30, 2004 at 10:30:54PM -0400, Pierre A. Humblet wrote:
>>At 01:39 PM 10/30/2004 -0400, you wrote:
>>>On Fri, Oct 29, 2004 at 06:01:51PM -0400, Pierre A. Humblet wrote:
>>>>Here is a patch that should allow unlink() to handle
>>>>nul etc.. on local disks.
>>>>It's a cut and paste of Corinna's open on NT and the
>>>>existing CreateFile.
>>>>It works on normal files. I haven't tested with the
>>>>special names because I forgot how to create them !
>>>>Feedback welcome.
>>>>XXXXX This should NOT be applied in 1.5.12 XXXXXX
>>>>2004-10-29  Pierre Humblet <>
>>>>	* (nt_delete): New function.
>>>>	(unlink): Call nt_delete instead of CreateFile and remove
>>>>	unreachable code.
>>>Corinna suggested something similar to me a couple of months ago but I
>>>wanted to wait for things to settle down somewhat after the original
>>>use of NtCreateFile.
>>>On reflection, however, wouldn't it be a little easier just to prepend
>>>the path being deleted with a: \\.\ so that "rm nul" would eventually
>>>translate to DeleteFile("\\.\c:\foo\null") (I'm not using true C
>>>backslash quoting here)?  I don't know if that would work on Windows 9x,
>>That would work on NT, but then one would need to check if the input
>>path didn't already have the form //./xx, worry about exceeding max 
>>pathlength, etc...
>Other than being able to delete special filenames is there any other
>benefit to using NtCreateFile to delete files?

I can only think of speed. But I don't see a downside either, given that
we use it in open().

>If path length was an issue we could use '//?/' instead since the length
>restriction is a lot larger there.  So, it would be something like:
>  char *path;
>  char newpath[strlen (win32_name) + 4] = "\\\\?\";
>  if  (win32_name[0] != '\\')
>      path = strcat (newpath, win32_name);
>  else
>      path = win32_name;
>and then you'd use path throughout from then on.

Have you tried it? According to MSDN you need to use the Unicode version
if you do that.
"In the ANSI version of this function, the name is limited to MAX_PATH 
characters. To extend this limit to 32,767 wide characters, call the Unicode 
version of the function and prepend "\\?\" to the path"


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