open files

Jim Salter jim at
Fri Feb 20 19:19:26 GMT 2004

Jason, this is absolutely great info on the Win32 file locking system 
and sounds like a very very interesting patch indeed.

A quick question, though - how hard would it be to use backup semantics 
as a default for an additional mount for the entire filesystem, rather 
than trying to tack it into rsync?  For example, we already have 
/cygdrive/c for the root c: filesystem, what if there were a 
/semantics/cygdrive/c to automatically attempt to use backup semantics 
if necessary on any file operations made on any of the files on the c: 

Just a thought.  Definitely not a kvetch.  But that would be an INSANELY 
useful addition to the cygwin package as a whole, and for the purists, 
file locking functionality definitely belongs more in the mounting of 
the filesystem itself than it does in rsync accessing a filesystem.


 > Jason M. Felice wrote:
> ... Since Windows
> programs can't rely on being able to open files that other programs have
> open, there would be no way to write a useful tape backup program.  To
> fix, they added "backup semantics".  If your process has permission to
> do so, it can request backup semantics which will allow it to open files
> which are already open.  
> ...
> The patch I'm working on will do this.  I'm promising people it'll be
> done by Monday (I hit a little roadblock in getting Cygwin to cooperate,
> hopefully I'll still be able to finish by then).  

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