How to write HDF5 dataset in C++ instead of C - c++

Question

English is not my native language; please excuse typing errors. This is code to read dataset from 400+ files with for loop to input in an big array.
float (*HaloPos)[3];//3D-positon(x-y-z)
int Nhalo= 1000000;//Suppose there are 1000000 particles in total number.
void readh5(int numfiles)
{
char fname[256];
int i, npart_cum;
hid_t hdf5_file, hdf5_grp, hdf5_dataspace_in_file;
hid_t hdf5_datatype, hddf5_dataspace_in_memory, hdf5_dataset;
hsize_t dims[2], count[2];
hsize_t start[2];
for(int task = 0; task < numfiles; task ++)
{
sprintf(fname,"%s.%d.hdf5",FILE_DIR,task);
cout<<"file name is"<<fname<<endl;
cout.flush();
read_header_attributes_in_hdf5(fname);
cout<<"npart = "<<header.npart<<endl;
cout.flush();
if(task == 0)
{
Nhalo = header.npartTotal[1];
npart_cum[1] = 0;
}
if(header.npart[1] > 0){
Group grp = file.openGroup("/PartType1");
read_halo(file, grp, task, npart_cum);
grp.close();
}
cout<<"task="<<task<<"halo particles have been read in."<<endl;
cout.flush();
file.close();
npart_cum += header.npart[1];
}
}
static void read_halo(H5File file, Group grp, int task, int npre)
{
hid_t hdf5_dataset;
/*--*/
if(task == 0)
if(!(HaloPos = malloc(sizeof(float)*Nhalo*3)))
exit(100);
printf("allocate positions\n");
fflush(stdout);
hdf5_dataset = H5Dopen(hdf5_grp,"Coordinates");
> get_float3(hdf5_file, hdf5_grp, hdf5_dataset, &HaloPos[npre][0]);
H5Dclose(hdf5_dataset);
}
static void read_header_attributes_in_hdf5(char *fname)
{
hid_thdf5_file,G hdf5_headergrphdf5_attribute;
hdf5_file = H5Fopen(fname, H5F_ACC_RDONLY, H5P_DEFAULT);
hdf5_headergrp = H5Gopen(hdf5_file, "/Header");
hdf5_attribute = H5Aopen_name(hdf5_headergrp, "NumPart_ThisFile");
H5Aread(hdf5_attribute, H5T_NATIVE_INT, &header.npart);
H5Aclose(hdf5_attribute);
}
static void get_float3(H5File file, Group grp, DataSet dset, float *fvec){
/* Open the dataset */
hid_t hdf5_datatype, hdf5_dataspace;
H5T_class_t hdf5_class;
H5T_order_t hdf5_order;
int status_n, rank;
hsize_t dims_out[2];
herr_t status;
hdf5_datatype = H5Dget_type(hdf5_dataset);
hdf5_class = H5Tget_class(hdf5_datatype);
if(hdf5_class != H5T_FLOAT)
exit(53);
hdf5_dataspace = H5Dget_space(hdf5_dataset); /* dataspace handle */
rank = H5Sget_simple_extent_ndims(hdf5_dataspace);
if(rank != 2)
exit(54);
status_n = H5Sget_simple_extent_dims(hdf5_dataspace, dims_out, NULL);
if(dims_out[1] != 3)
exit(55);
status = H5Dread(hdf5_dataset, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL,
H5P_DEFAULT, fvec);
H5Tclose(hdf5_datatype);
}
}
The code is not complete, but the main thing I want to ask everyone is how to use dataset.read instead of H5Dread to read the data and add after the array after one loop
In my limited experience with C++
actually I tried using vector replace array, but I want to know how to write in c++
After I changed background in c++. The code I just changed
status = H5Dread(hdf5_dataset, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL,
H5P_DEFAULT, fvec);
to
dataset.read(fvec,datatype);
And I found the dataset read defination is different in c and c++
in c++
void read ( void * buf,
const DataType & mem_type,
const DataSpace & mem_space = DataSpace::ALL,
const DataSpace & file_space = DataSpace::ALL,
const DSetMemXferPropList & xfer_plist = DSetMemXferPropList::DEFAULT
) const
void read ( H5std_string & buf,
const DataType & mem_type,
const DataSpace & mem_space = DataSpace::ALL,
const DataSpace & file_space = DataSpace::ALL,
const DSetMemXferPropList & xfer_plist = DSetMemXferPropList::DEFAULT
) const
and in c
H5Dread (hid_t dset_id, hid_t mem_type_id, hid_t mem_space_id, hid_t file_space_id, hid_t dxpl_id, void *buf)
Could someone help about how to write in c++?Thanks in advance.