Hi Jim, On Apr 22, 2014, at 10:17 AM, "Rowe, Jim" <j.r...@questintegrity.com> wrote:
> Elena, > Ok, thank you—sound like a personals ad. ;-) Can you clarify how SWMR mode > is used? When an HDF5 file is open by writer process for SWMR access, the flag is set up by the HDF5 library so no other writer process can open the file. Any number of processes can open the file for reading. > Is that part of building it thread-safe? No. > That functionality would address most of the issues for my app. We hope so! All, SWMR is still "under construction" (we are looking into a few performance issues and documentation needs more work). Below are some pointers to source and documentation. SWMR prototype source code is available from ftp://ftp.hdfgroup.uiuc.edu/pub/outgoing/SWMR/src/ Please check the README file in ftp directory. It contains installation instructions, the list of the file systems on which SWMR runs and the programming model to follow. Documentation is available at http://www.hdfgroup.org/projects/SWMR/. Please be aware that SWMR writer will create files that are not readable by the HDF5 1.8.* libraries and tools. One will need to run h5repack from the SWMR distribution to create 1.8 file; solution for the 1.8 - 1.10 forward compatibility is in the works. We are planning to organize a Web seminar on SWMR in June. Please send me an email if you are interested in participating. Thank you! Elena > > Warm Regards, > Jim > > From: Hdf-forum [mailto:hdf-forum-boun...@lists.hdfgroup.org] On Behalf Of > Elena Pourmal > Sent: Monday, April 21, 2014 10:22 PM > To: HDF Users Discussion List > Subject: Re: [Hdf-forum] Access violation after deleting link and recreating > dataset > > Hi Jim, > > On Apr 20, 2014, at 11:56 PM, "Rowe, Jim" <j.r...@questintegrity.com> wrote: > > > Thank you, Elena. I think my problem was due to multi-threading issues in my > client app. A separate thread(s) was accessing the file through a different > fileid. I’ve reworked my thread synchronization and am preventing multiple > instances from getting created and all is looking good. > > Is there a simple way to just open the file for exclusive access? Similar to > share_exlusive flag for windows OpenFile function. It seems that would > prevent other threads > and processes from accessing it. Unless I am missing something, the only H5f > open flags are read-only and read/write. > > Unfortunately, there is no a simple way to open the file for exclusive access > with the current HDF5. We contemplated the idea for the next major release, > but implemented it only for the SWMR (single writer-multiple reader) mode. > > Preventing file access by multiple writers or single writer/multiple readers > without using SWMR mode will definitely make HDF5 little-bit more > user-friendly ;-)! We may implement in the future. > > Thank you! > > Elena > > > Warm Regards, > Jim > > From: Hdf-forum [mailto:hdf-forum-boun...@lists.hdfgroup.org] On Behalf Of > Elena Pourmal > Sent: Thursday, April 17, 2014 6:08 PM > To: HDF Users Discussion List > Subject: Re: [Hdf-forum] Access violation after deleting link and recreating > dataset > > Jim, > > A short program that demonstrates the issue would be helpful. > > I just tried in C and couldn't make it to fail (probably haven't try hard :-) > > #include "hdf5.h" > #define FILE "dset.h5" > > int main() { > > hid_t file_id, dataset_id, dataspace_id; /* identifiers */ > hsize_t dims[2]; > herr_t status; > > > /* Create the data space for the dataset. */ > dims[0] = 4; > dims[1] = 6; > dataspace_id = H5Screate_simple(2, dims, NULL); > > /* Create a new file using default properties. */ > file_id = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT); > > /* Create the dataset. */ > dataset_id = H5Dcreate2(file_id, "/dset", H5T_STD_I32BE, dataspace_id, > H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT); > > status = H5Dclose(dataset_id); > > /* Delete the dataset. */ > H5Ldelete (file_id, "/dset", H5P_DEFAULT); > H5Fflush(file_id, H5F_SCOPE_GLOBAL); > > dataset_id = H5Dcreate2(file_id, "/dset", H5T_STD_I32BE, dataspace_id, > H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT); > status = H5Dclose(dataset_id); > > status = H5Sclose(dataspace_id); > status = H5Fclose(file_id); > } > > Elena > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Elena Pourmal The HDF Group http://hdfgroup.org > 1800 So. Oak St., Suite 203, Champaign IL 61820 > 217.531.6112 > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > > > > > > On Apr 17, 2014, at 5:01 PM, "Rowe, Jim" <j.r...@questintegrity.com> wrote: > > > > Hello- I am consistently getting access violations after doing the following: > > H5L.Delete(_H5FileId, dataSetPath); > H5F.flush(_H5FileId, H5F.Scope.GLOBAL); > // setup for create call omitted > H5D.create( … ) //creates same structure dataset to same dataSetPath > > My intent is to completely clear out the dataset by removing and recreating > it. Is there a preferred way to do this? Is H5L not the right call? > > Any help would be appreciated. > > Warm Regards, > Jim > _______________________________________________ > Hdf-forum is for HDF software users discussion. > Hdf-forum@lists.hdfgroup.org > http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > Hdf-forum@lists.hdfgroup.org > http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > Hdf-forum@lists.hdfgroup.org > http://mail.lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org
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