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+/*
+ * This example shows how to create a compound data type,
+ * write an array which has the compound data type to the file,
+ * and read back fields' subsets.
+ */
+
+#include "hdf5.h"
+
+#define FILE "SDScompound.h5"
+#define DATASETNAME "ArrayOfStructures"
+#define LENGTH 10
+#define RANK 1
+
+int
+main(void)
+{
+
+ /* First structure and dataset*/
+ typedef struct s1_t {
+ int a;
+ float b;
+ double c;
+ } s1_t;
+ s1_t s1[LENGTH];
+ hid_t s1_tid; /* File datatype identifier */
+
+ /* Second structure (subset of s1_t) and dataset*/
+ typedef struct s2_t {
+ double c;
+ int a;
+ } s2_t;
+ s2_t s2[LENGTH];
+ hid_t s2_tid; /* Memory datatype handle */
+
+ /* Third "structure" ( will be used to read float field of s1) */
+ hid_t s3_tid; /* Memory datatype handle */
+ float s3[LENGTH];
+
+ int i;
+ hid_t file, dataset, space; /* Handles */
+ herr_t status;
+ hsize_t dim[] = {LENGTH}; /* Dataspace dimensions */
+
+
+ /*
+ * Initialize the data
+ */
+ for (i = 0; i< LENGTH; i++) {
+ s1[i].a = i;
+ s1[i].b = i*i;
+ s1[i].c = 1./(i+1);
+ }
+
+ /*
+ * Create the data space.
+ */
+ space = H5Screate_simple(RANK, dim, NULL);
+
+ /*
+ * Create the file.
+ */
+ file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+
+ /*
+ * Create the memory data type.
+ */
+ s1_tid = H5Tcreate (H5T_COMPOUND, sizeof(s1_t));
+ H5Tinsert(s1_tid, "a_name", HOFFSET(s1_t, a), H5T_NATIVE_INT);
+ H5Tinsert(s1_tid, "c_name", HOFFSET(s1_t, c), H5T_NATIVE_DOUBLE);
+ H5Tinsert(s1_tid, "b_name", HOFFSET(s1_t, b), H5T_NATIVE_FLOAT);
+
+ /*
+ * Create the dataset.
+ */
+ dataset = H5Dcreate(file, DATASETNAME, s1_tid, space, H5P_DEFAULT);
+
+ /*
+ * Wtite data to the dataset;
+ */
+ status = H5Dwrite(dataset, s1_tid, H5S_ALL, H5S_ALL, H5P_DEFAULT, s1);
+
+ /*
+ * Release resources
+ */
+ H5Tclose(s1_tid);
+ H5Sclose(space);
+ H5Dclose(dataset);
+ H5Fclose(file);
+
+ /*
+ * Open the file and the dataset.
+ */
+ file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT);
+
+ dataset = H5Dopen(file, DATASETNAME);
+
+ /*
+ * Create a data type for s2
+ */
+ s2_tid = H5Tcreate(H5T_COMPOUND, sizeof(s2_t));
+
+ H5Tinsert(s2_tid, "c_name", HOFFSET(s2_t, c), H5T_NATIVE_DOUBLE);
+ H5Tinsert(s2_tid, "a_name", HOFFSET(s2_t, a), H5T_NATIVE_INT);
+
+ /*
+ * Read two fields c and a from s1 dataset. Fields in the file
+ * are found by their names "c_name" and "a_name".
+ */
+ status = H5Dread(dataset, s2_tid, H5S_ALL, H5S_ALL, H5P_DEFAULT, s2);
+
+ /*
+ * Display the fields
+ */
+ printf("\n");
+ printf("Field c : \n");
+ for( i = 0; i < LENGTH; i++) printf("%.4f ", s2[i].c);
+ printf("\n");
+
+ printf("\n");
+ printf("Field a : \n");
+ for( i = 0; i < LENGTH; i++) printf("%d ", s2[i].a);
+ printf("\n");
+
+ /*
+ * Create a data type for s3.
+ */
+ s3_tid = H5Tcreate(H5T_COMPOUND, sizeof(float));
+
+ status = H5Tinsert(s3_tid, "b_name", 0, H5T_NATIVE_FLOAT);
+
+ /*
+ * Read field b from s1 dataset. Field in the file is found by its name.
+ */
+ status = H5Dread(dataset, s3_tid, H5S_ALL, H5S_ALL, H5P_DEFAULT, s3);
+
+ /*
+ * Display the field
+ */
+ printf("\n");
+ printf("Field b : \n");
+ for( i = 0; i < LENGTH; i++) printf("%.4f ", s3[i]);
+ printf("\n");
+
+ /*
+ * Release resources
+ */
+ H5Tclose(s2_tid);
+ H5Tclose(s3_tid);
+ H5Dclose(dataset);
+ H5Fclose(file);
+
+ return 0;
+}