file locking (F_GETLK) porting workaround anyone???

file locking (F_GETLK) porting workaround anyone???

[hardon]

Any known workaround for the unimplemented F_GETLK, file locking func???
Whats the big deal with this thing anyway??
If we don't need the lockers pid, just try std. lock and check for errors, 
right??

Gunnar Dalsnes.


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Re: file locking (F_GETLK) porting workaround anyone???

[Corinna Vinschen]

On Mon, Jul 09, 2001 at 09:56:20AM +0200, hardon wrote:
> Any known workaround for the unimplemented F_GETLK, file locking func???
> Whats the big deal with this thing anyway??
> If we don't need the lockers pid, just try std. lock and check for errors, 
> right??

You're welcome to contribute F_GETLK and F_SETLK(W) in Cygwin if you've
found a way to implement them correctly.

Corinna

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Re: Re: file locking (F_GETLK) porting workaround anyone???

[Gunnar Andre Dalsnes]

At 09.07.01 10:28, you wrote:
>On Mon, Jul 09, 2001 at 09:56:20AM +0200, hardon wrote:
>> Any known workaround for the unimplemented F_GETLK, file locking func???
>> Whats the big deal with this thing anyway??
>> If we don't need the lockers pid, just try std. lock and check for errors, 
>> right??
>
>You're welcome to contribute F_GETLK and F_SETLK(W) in Cygwin if you've
>found a way to implement them correctly.

What's wrong with F_SETLK(W)? Missing signal interrupt support? 
If so, could consistent asynchronous file IO (on NT) fix this?
LockFileEx do support asynchronous IO.

Proper implementation of F_GETLK could be done (on NT) with use of a kernel mode filesystem filter driver.


>Corinna
>
>-- 
>Corinna Vinschen                  Please, send mails regarding Cygwin to
>Cygwin Developer                                mailto:cygwin@cygwin.com
>Red Hat, Inc.
>
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Re: Re: file locking (F_GETLK) porting workaround anyone???

[Corinna Vinschen]

On Mon, Jul 16, 2001 at 01:10:59AM +0200, Gunnar Andre Dalsnes wrote:
> At 09.07.01 10:28, you wrote:
> >On Mon, Jul 09, 2001 at 09:56:20AM +0200, hardon wrote:
> >> Any known workaround for the unimplemented F_GETLK, file locking func???
> >> Whats the big deal with this thing anyway??
> >> If we don't need the lockers pid, just try std. lock and check for errors, 
> >> right??
> >
> >You're welcome to contribute F_GETLK and F_SETLK(W) in Cygwin if you've
> >found a way to implement them correctly.
> 
> What's wrong with F_SETLK(W)? Missing signal interrupt support? 
> If so, could consistent asynchronous file IO (on NT) fix this?
> LockFileEx do support asynchronous IO.

At least three problems here:

- LockFileEx() is not implemented on 9x/ME.
- Lock requests given to LockFileEx() may not overlap existing locked
  regions of the file.
- There's not nearly a functionality similar to F_GETLK in the Win32 API.

Corinna

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