Allen, Thank you for your report! On Jan 14, 2010, at 12:37 PM, Allen Sanderson wrote:
> HI, > > This morning I was able to track down a bug with a file with external links > where the file was opened twice simultaneously. The first open was read only. > The second open was read write. However, if I create the file with the exact > same hierarchy but without links I do not see the bug. I found this odd. > > Here is the sequence > > fp1 = open file read only > > gp1 = open /group using fp1 (note /group is an eternal link) > > fp2 = open file read/write > > dp2 = open /group/dataset using fp2 > > the last open fails. I can understand the failure given the gp1 is read only > and dp2 which is under it is trying to perhaps do a write which could cause > some problems. So it fails. > > However, if the file has the same hierarchy but without the link it does not > fail. I found this behavior strange as I would have expected both to behave > the same. > > Obviously, one solution is not to open the file twice which is certainly > possible but also having both opens be read/write also works. But I am more > concerned with the inconsistency. > yes, good point. Could you please send us an error stack from the failed program? In our defense :-) RM entry for H5Fopen states "A file can often be opened with a new H5Fopen call without closing an already-open identifier established in a previous H5Fopen or H5Fcreate call. Each such H5Fopen call will return a unique identifier and the file can be accessed through any of these identifiers as long as the identifier remains valid. In such multiply-opened cases, all the open calls should use the same flags argument." Elena > > Cheers, > > Allen > > > Allen Sanderson > SCI Institute > University of Utah > www.sci.utah.edu > > > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > [email protected] > http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
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