Searching a HDF5 dataset

Question

I\'m currently exploring HDF5. I\'ve read the interesting comments from the thread \"Evaluating HDF5\" and I understand that HDF5 is a solution of choice for storing the dat

Answer 1

H5Lexists was introduced for this in HDF5 1.8.0:

http://www.hdfgroup.org/HDF5/doc/RM/RM_H5L.html#Link-Exists

You can also iterate over the things that are in an HDF5 file with H5Literate:

http://www.hdfgroup.org/HDF5/doc/RM/RM_H5L.html#Link-Iterate

But you can also manually check for previous versions by trying to open a dataset. We use code like this to deal with any version of HDF5:

bool DoesDatasetExist(const std::string& rDatasetName)
{
#if H5_VERS_MAJOR>=1 && H5_VERS_MINOR>=8
    // This is a nice method for testing existence, introduced in HDF5 1.8.0
    htri_t dataset_status = H5Lexists(mFileId, rDatasetName.c_str(), H5P_DEFAULT);
    return (dataset_status>0);
#else
    bool result=false;
    // This is not a nice way of doing it because the error stack produces a load of 'HDF failed' output.
    // The "TRY" macros are a convenient way to temporarily turn the error stack off.
    H5E_BEGIN_TRY
    {
        hid_t dataset_id = H5Dopen(mFileId, rDatasetName.c_str());
        if (dataset_id>0)
        {
            H5Dclose(dataset_id);
            result = true;
        }
    }
    H5E_END_TRY;
    return result;
#endif
}