One more thing, I also removed the '&' from "&str" in: readError = H5Aread(attribHandler,attribType,&str);
Binh-Minh ________________________________ From: Hdf-forum <[email protected]> on behalf of Binh-Minh Ribler <[email protected]> Sent: Monday, July 27, 2015 3:07 PM To: HDF Users Discussion List Subject: Re: [Hdf-forum] Weird H5Aread() error in HDF5 files - possibly a bug Hi Samer, I think it has something to do with variable-length vs. fixed-length string for the attribute. I tried your program and got segfault too. Then I saw that you passed in an un-allocated "str" to HDF5Attribute<std::string>::readAttribute() for an attribute which seemed to be a fixed-length type, so I allocated "str" and the segfault went away. Here is the output. Does it look right? Success read file into memory: 0 12:21:12.222 21:22:11.444 1000 Program ended normally I removed the free too. Binh-Minh ________________________________ From: Hdf-forum <[email protected]> on behalf of Samer Afach <[email protected]> Sent: Thursday, July 23, 2015 5:35 PM To: HDF Users Discussion List Subject: Re: [Hdf-forum] Weird H5Aread() error in HDF5 files - possibly a bug Dear Gerd, Dear experts in hdf: The problem is even beyond reading the string (the string I wrote is a scalar). Here I present the problem. To make the problem clearer, I created a compilable minimal example by truncating parts of my program and resorting it, in order to show the problem's weird behavior. Please compile the main.cpp file with g++ main.cpp -std=c++11 -lhdf5_hl -lhdf5 -lhdf5_hl_cpp -lhdf5_cpp -lszip -lz -ldl -o exe The program creates a data file, writes it, reads it again to a string buffer, then opens it with H5LTopen_file_image(). This will cause the program to crash when trying to read attributes. Nothing works properly with image opening for some reason. I even introduced std::vector<char> to ensure contiguity in memory. On the other hand, the provided Example.hdf5, which was provided by a colleague, and produced with Labview, and is only different that it uses a compound type, can be read by my program with no problems at all. All you have to do, is uncomment the part of the code that has the file name Example.hdf5 in main.cpp, and see how attributes get printed with no problems. I really, really would appreciate your help. I'm so shocked because my software was supposed to be ready today and I was supposed to present it, and this problem suddenly happened. Now I'm giving excuses to people on why it's not done. I've been working on this for more than 8 hours with no result. Thank you, and I really appreciate any efforts. All the best, Samer On 23.07.2015 21:16, Gerd Heber wrote: Is the string a (1) fixed-length or (2) variable-length string? (What does h5dump say? Or programmatically via "htri_t H5Tis_variable_str( hid_t dtype_id )"...) Your code should work fine for (2) and a scalar attribute, but won't work with (1). You'd have to allocate the buffer for the string(s) in (1) yourself. G. -----Original Message----- From: Hdf-forum [mailto:[email protected]] On Behalf Of [email protected]<mailto:[email protected]> Sent: Thursday, July 23, 2015 11:55 AM To: HDF Users Discussion List Subject: [Hdf-forum] Weird H5Aread() error in HDF5 files - possibly a bug Dear pros: So a colleague of mine created an HDF5 for testing purposes using Labview, and I used my C++ program to read attributes from it, and that worked with the attached function with no problem. Now I created my own HDF5 files with exactly the same structure, but with the difference that I'm using non-compound types. The attribute names are exactly the same. So I started my program and loaded my new files exactly like I do with the other files I got from my colleague, and got a crash. I pursued the issue with a debugger and found the situation attached in the image. It's a very weird situation that I can't understand. On the right, you'll find that all values are positive and read return is zero (so no error), and yet the assignment operator is throwing an error and the variable str, which is char*, is not accessible. How could this happen? I could provide any additional information you require. Thank you for any help you provide. All the best, Samer _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected]<mailto:[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
