file mapped bigarray and Unix.unlink

file mapped bigarray and Unix.unlink

[Matthieu Dubuget]

Hello,

I have difficulties to delete one file (name: fn, file descriptor:
fdesc) with "Unix.unlink fn".

I suspect that this is because I have a bigarray ba mapped with fdesc.
Is it a possible reason?

At some point, I want to delete fn because the saving operation was
cancelled by the user.

I assure that the binding to ba is lost.

Then, I close the file handle with
"Unix.close fdesc;"

At this point,
"Unix.rename fn g;" works, but
 
"Unix.unlink fn;" fails with : Permission denied error.


following my idea that this can be due to the fact that fn is mapped in
memory, I tried to insert a Gc.compact, in order for ba to be erased:

Unix.close fdesc;
Gc.compact ();
Unix.unlink fn;

but got the same error message.

Any idea?

Salutations

Matt

Re: [Caml-list] file mapped bigarray and Unix.unlink

[Matthieu Dubuget]

Solved! Sorry for the noise.

The operating systems takes time to free the file descriptor.
The strategy I adopted is to spawn a recursive thread that
periodically try to erase the file until success.

Salutations

Re: [Caml-list] file mapped bigarray and Unix.unlink

[David MENTRE]

Hello Mathieu,

2009/7/2 Matthieu Dubuget <matthieu.dubuget@gmail.com>:
> The strategy I adopted is to spawn a recursive thread that
> periodically try to erase the file until success.

That seems the wrong solution to me. The unlink syscall should work
immediately or you have another reason why it only works after a
certain time.

Yours,
david

Re: [Caml-list] file mapped bigarray and Unix.unlink

[Matthieu Dubuget]

| Sujet : « Re: [Caml-list] file mapped bigarray and Unix.unlink »
| Pour : « matthieu.dubuget@gmail.com »
| De : « David MENTRE <dmentre@linux-france.org> »
| Le  Thu Jul 02 2009 11:49:33 GMT+0200 (CEST)
> Hello Mathieu,
>
> 2009/7/2 Matthieu Dubuget <matthieu.dubuget@gmail.com>:
>   
>> The strategy I adopted is to spawn a recursive thread that
>> periodically try to erase the file until success.
>>     
>
> That seems the wrong solution to me. The unlink syscall should work
> immediately or you have another reason why it only works after a
> certain time.
>
> Yours,
> david
>   

I agree… but:
- I'm already late (I know, that's a bad reason)
- I don't know what could be the reason(s) for this delay

Thanks

Matt

Re: [Caml-list] file mapped bigarray and Unix.unlink

[Florian Hars]

Matthieu Dubuget schrieb:
> Any idea?

You are probably using windows, which is a bit weird about operations
on open files.

- Florian.

Re: [Caml-list] file mapped bigarray and Unix.unlink

[Dario Teixeira]

Hi,

> > The strategy I adopted is to spawn a recursive thread that
> > periodically try to erase the file until success.
> 
> That seems the wrong solution to me. The unlink syscall should work
> immediately or you have another reason why it only works after a
> certain time.

I second David's discomfort.  Have you considered issuing a sync after
the unlink?  For efficiency reasons the OS may not actually be deleting
the file immediately after the unlink; the sync should force it to do it.

Cheers,
Dario Teixeira