Hmm. I know at least some of the VFD's in HDF5 maintain 'internal' knowledge of the file's current offset apart from the underlying FILE* stream or int fd desriptor to which they refer. So, if you did get in there and do a seek or read operation, you'd need to make sure you returned the FILE* stream of int fd to the state it was in BEFORE you did anything. Otherwise, HDF5 and the underlying file object wouldn't agree about where they are pointing.
Out of curiosity, what does get_vfd_handle return for the core vfd? Does it return the actual buffer the core vfd is writing to? Is it even implemented for core? Mark On Fri, 2010-03-26 at 13:26, Andrew Collette wrote: > Hi, > > Does anyone know if it's possible to read/modify the user block > associated with an open HDF5 file? The documentation for > H5Fget_vfd_handle says not to use the returned handle to modify the > file... is it safe to do things like seeking and reading? > > Thanks, > Andrew Collette > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > [email protected] > http://*mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org -- Mark C. Miller, Lawrence Livermore National Laboratory ================!!LLNL BUSINESS ONLY!!================ [email protected] urgent: [email protected] T:8-6 (925)-423-5901 M/W/Th:7-12,2-7 (530)-753-851 _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
