H5Acreate example: Show how to create an attribute for a dataset and a group
file=H5Fopen("example.h5", H5F_ACC_RDWR, H5P_DEFAULT);
/* Describe the size of the array and create the data space */
dimsf[0] = H5S_UNLIMITED;
dimsf[1] = H5S_UNLIMITED;
dataspace = H5Screate_simple(rank, dimsf, NULL);
dataset=H5Dcreate(file,"Dataset1",H5T_UINT8,dataspace,H5P_DEFAULT);
<Write data to first dataset>
/* Create an attribute for the dataset */
attr=H5Acreate(dataset,"Attr1",H5T_INT32,H5S_SCALAR,H5P_DEFAULT);
/* Write attribute information */
H5Awrite(attr,H5T_INT32,&attr_data);
group=H5Gcreate(file,"/Group One",0);
/* Create an attribute for the dataset */
attr=H5Acreate(group,"Attr1",H5T_INT32,H5S_SCALAR,H5P_DEFAULT);
/* Write attribute information */
H5Awrite(attr,H5T_INT32,&attr_data);