2016-11-28 23:28 GMT+01:00 Landon Clipp <[email protected]>: > Also one more possible issue I'd add onto my list there: it is possible > that the file is corrupt. So try ruling that out by making an empty HDF5 > file in the same directory as the one you're trying to access and run the > same functions, only opening this new file instead. > Ah yes, sorry I should have been more clear: In my case I wasn't debugging a particular failure, just looking for a way to get as much info out of HDF5 as possible to present together with an error message to the user (it's a GUI application) (see also my response to Rob just now).
Thanks for this suggestion and the ones below as well though. They will surely help when things truly hit the fan :) Elvis > Regards, > Landon > > On Nov 28, 2016 4:26 PM, "Landon Clipp" <[email protected]> wrote: > >> Mark, >> >> I get what you mean. I have rarely found the error output of HDF5 to be >> of much use, although sometimes it can be helpful. For instance just off >> the top of my head, I've been getting errors about HDF attributes. I've >> called H5Aclose and I get errors about the argument not being an attribute. >> Turns out the variable I passed was never initialized. So in that case it's >> helpful. >> >> One thing to realize is that the error is most likely NOT reading in the >> library itself. I recommend that you use a debugger like GDB to find >> exactly what you are passing into the function and to see if every value >> you're passing in makes sense. That's really the only way to go about it. >> >> It all comes down to this: H5Fopen is failing and there are a finite >> number of issues we can address. >> >> 1. Does the file exist, and if so are you providing the correct path to >> it (relative or absolute)? Do you have read/write permission for the file? >> 2. Have you misspelled the file? >> 3. Are you providing either DF_ACC_RDWR or DF_ACC_RDONLY to the second >> argument? Only those two arguments are valid. >> 4. What file access property list are you providing? You should be able >> to rule out providing a buggy access property by just passing in the >> default parameter. >> >> I guarantee that your error lies in one of these issues. I recommend you >> make the second and third arguments the read only and default respectively. >> That will isolate the problem to your first argument and whether or not you >> have appropriate file permissions. >> >> Regards, >> Landon >> >> On Nov 28, 2016 3:33 PM, "Miller, Mark C." <[email protected]> wrote: >> >>> "Hdf-forum on behalf of Rob Latham" wrote: >>> >>> >>> I think you are going to have to share your output with the list. >>> Whenever *I* run hdf5 and get an error I get screenfuls of information. >>> >>> For example, here's a simple hdf5 program trying to open a file for >>> which I have removed all read and write permissions: >>> >>> HDF5-DIAG: Error detected in HDF5 (1.8.16) thread 0: >>> #000: ../../../hdf5-1.8.16/src/H5F.c line 604 in H5Fopen(): unable to >>> open file >>> major: File accessibilty >>> minor: Unable to open file >>> #001: ../../../hdf5-1.8.16/src/H5Fint.c line 992 in H5F_open(): >>> unable to open file: time = Mon Nov 28 14:41:40 2016 >>> , name = 'try.h5', tent_flags = 1 >>> major: File accessibilty >>> minor: Unable to open file >>> #002: ../../../hdf5-1.8.16/src/H5FD.c line 993 in H5FD_open(): open >>> failed >>> major: Virtual File Layer >>> minor: Unable to initialize object >>> #003: ../../../hdf5-1.8.16/src/H5FDsec2.c line 339 in >>> H5FD_sec2_open(): unable to open file: name = 'try.h5', errno = 13, >>> error message = 'Permission denied', flags = 1, o_flags = 2 >>> major: File accessibilty >>> minor: Unable to open file >>> >>> >>> >>> I am not sure how other users feel about this and it may not even be the >>> original poster's ( Elvis Stansvik) complaint but a big challenge I have >>> with interpreting HDF5 errors *is* the "...screenfuls of information". >>> >>> It is challenging to paw through it to discover the root cause. >>> >>> For example, in the above error stack, we get information about why sec2 >>> VFD failed..."errno=13 ("Permission enied") but what are 'flags' and >>> 'o_flags' there? Are these params to sec2 open call? That has only an >>> 'oflag' argument and not an additional 'flags' argument. And, their numeric >>> values, '1' and '2' are too informatvie either. What about similar info at >>> the HDF5 public interface (e.g. H5Fopen)? What was passed for 'flags' >>> there. Oh, maybe 'flags' in the #003 trace *is* the 'flags' argument caller >>> passed to H5Fopen and 'o_flags' is what HDF5 lib passed to sec2 open call? >>> I could see having 'flags' emitted in the #000 trace if that is indeed the >>> argument passed as 'flags' to H5Fopen. and 'oflags' not 'o_flags' emitted >>> in the #003 trace. Finally, it would be *much* more helpful to see the >>> symbolic constants for the flags and not their numerics. >>> >>> So, I personally find grocking HDF5 error stack output very awkward. >>> >>> It may be that it is awkward enough for others that no one really is >>> able to find the information they needed in it (e.g. the signal to noise >>> ratio is just way too low). >>> >>> My two cents. >>> >>> Mark >>> >>> -- >>> Mark C. Miller, LLNL >>> >>> "In the end, we will remember not the words of >>> our enemies but the silence of our friends" - MLK >>> >>> _______________________________________________ >>> Hdf-forum is for HDF software users discussion. >>> [email protected] >>> http://lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org >>> Twitter: https://twitter.com/hdf5 >>> >> > _______________________________________________ > Hdf-forum is for HDF software users discussion. > [email protected] > http://lists.hdfgroup.org/mailman/listinfo/hdf-forum_lists.hdfgroup.org > Twitter: https://twitter.com/hdf5 >
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