[Hdf-forum] Following external links - permissions

[Quincey Koziol]

Hi Allen,

On Dec 19, 2009, at 1:33 PM, allen wrote:

> Hi Quincey,
> 
> I am currently using 1.8.2.
> 
> One other clue, this only happens when I utilize one particular piece of code (a third party lib). If I skip it then the link is followed fine later (I access it in multiple places). So I think the link and the permissions are okay but how this third party code opens the link initially tends to make it inaccessible later on. So my guess is that this particular piece of code pooches something. I have not started looking at it yet. (Probably will be able to as my hard drive on that machine died Friday night).
> 
> Some random thoughts if the file was initially opened as RDONLY with that link accessed. If opening the file again as RDWR would that force the access to that link to fail?

	Yes, that would cause the second access to fail.

> If there a way to see what groups are currently  open?

	You can use the H5Fget_obj_count/H5Fget_obj_ids routines to investigate this.

	Quincey


> Cheers,
> 
> Allen
> 
> 
> Allen Sanderson
> SCI Institute
> University of Utah
> www.sci.utah.edu
> 
> 
> 
> On Dec 18, 2009, at 10:22 PM, Quincey Koziol wrote:
> 
>> Hi Allen,
>> 
>> On Dec 18, 2009, at 7:07 PM, Allen Sanderson wrote:
>> 
>>> One followup could this problem be related to perhaps already having the one link open ??? and then trying to open it again???
>> 
>> 	Hmm, are you using the latest release (1.8.4)?
>> 
>> 	Quincey
>> 
>>> 
>>> 
>>> Cheers,
>>> 
>>> Allen 
>>> 
>>> 
>>> 
>>> 
>>> On Dec 18, 2009, at 6:02 PM, Allen Sanderson wrote:
>>> 
>>>> I have a file with two external links that at are both at the top level:
>>>> 
>>>> HDF5 "DATA.h5" {
>>>> GROUP "/" {
>>>>     EXTERNAL_LINK "Mesh" {
>>>>       TARGETFILE "Mesh.h5"
>>>>       TARGETPATH "/Mesh"
>>>>          GROUP "/Mesh" {
>>>>       }
>>>>     }
>>>>    EXTERNAL_LINK "Step#0" {
>>>>       TARGETFILE "step_0.h5"
>>>>       TARGETPATH "/Step#0"
>>>>          GROUP "/Step#0" {
>>>>       }
>>>>     }
>>>>   }
>>>> }
>>>> 
>>>> When I open the main file, DATA.h5 as RDONLY I am able to traverse both links as one would expect. 
>>>> 
>>>> However, when I open the main file, DATA.h5 as RDWR the group "/Mesh" succeeds but the "Step#0" fails. Both links are created in the exact same manner. 
>>>> 
>>>>  if( H5Lcreate_external(MESH_NAME, "/Mesh",
>>>> 			 file_id, "Mesh",
>>>> 			 H5P_DEFAULT, H5P_DEFAULT) < 0 ) {
>>>>  }
>>>> 
>>>> So I am at a loss as to why the access is different. I tried to follow through and understand more on the Property list that is set to teh default. ie this var:
>>>> hid_t lapl_id	IN: Link access property list identifier.
>>>> 
>>>> but I did not get far. Should I be setting something here???? 
>>>> 
>>>>  
>>>> Cheers,
>>>> 
>>>> Allen
>>>> 
>>>> 
>>>> Allen Sanderson
>>>> SCI Institute
>>>> University of Utah
>>>> www.sci.utah.edu
>>>> 
>>>> 
>>>> 
>>>> _______________________________________________
>>>> Hdf-forum is for HDF software users discussion.
>>>> Hdf-forum at hdfgroup.org
>>>> http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
>>> 
>>> _______________________________________________
>>> Hdf-forum is for HDF software users discussion.
>>> Hdf-forum at hdfgroup.org
>>> http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
>> 
>> _______________________________________________
>> Hdf-forum is for HDF software users discussion.
>> Hdf-forum at hdfgroup.org
>> http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
> 
> _______________________________________________
> Hdf-forum is for HDF software users discussion.
> Hdf-forum at hdfgroup.org
> http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org

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