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+/************************************************************
+
+ This example shows how to read and write data to an
+ external dataset. The program first writes integers to an
+ external dataset with dataspace dimensions of DIM0xDIM1,
+ then closes the file. Next, it reopens the file, reads
+ back the data, and outputs the name of the external data
+ file and the data to the screen.
+
+ This file is intended for use with HDF5 Library version 1.6
+
+ ************************************************************/
+
+#include "hdf5.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+#define FILE "h5ex_d_extern.h5"
+#define EXTERNAL "h5ex_d_extern.data"
+#define DATASET "DS1"
+#define DIM0 4
+#define DIM1 7
+#define NAME_BUF_SIZE 32
+
+int
+main(void)
+{
+ hid_t file, space, dset, dcpl; /* Handles */
+ herr_t status;
+ hsize_t dims[2] = {DIM0, DIM1};
+ char name[NAME_BUF_SIZE];
+ int wdata[DIM0][DIM1], /* Write buffer */
+ rdata[DIM0][DIM1], /* Read buffer */
+ i, j;
+
+ /*
+ * Initialize data.
+ */
+ for (i = 0; i < DIM0; i++)
+ for (j = 0; j < DIM1; j++)
+ wdata[i][j] = i * j - j;
+
+ /*
+ * Create a new file using the default properties.
+ */
+ file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+
+ /*
+ * Create dataspace. Setting maximum size to NULL sets the maximum
+ * size to be the current size.
+ */
+ space = H5Screate_simple(2, dims, NULL);
+
+ /*
+ * Create the dataset creation property list, set the external
+ * file.
+ */
+ dcpl = H5Pcreate(H5P_DATASET_CREATE);
+ status = H5Pset_external(dcpl, EXTERNAL, 0, H5F_UNLIMITED);
+
+ /*
+ * Create the external dataset.
+ */
+ dset = H5Dcreate(file, DATASET, H5T_STD_I32LE, space, dcpl);
+
+ /*
+ * Write the data to the dataset.
+ */
+ status = H5Dwrite(dset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata[0]);
+
+ /*
+ * Close and release resources.
+ */
+ status = H5Pclose(dcpl);
+ status = H5Dclose(dset);
+ status = H5Sclose(space);
+ status = H5Fclose(file);
+
+ /*
+ * Now we begin the read section of this example.
+ */
+
+ /*
+ * Open file and dataset using the default properties.
+ */
+ file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT);
+ dset = H5Dopen(file, DATASET);
+
+ /*
+ * Retrieve dataset creation property list.
+ */
+ dcpl = H5Dget_create_plist(dset);
+
+ /*
+ * Retrieve and print the name of the external file. Here we
+ * manually set the last field in name to null, in case the name of
+ * the file is longer than the buffer.
+ */
+ status = H5Pget_external(dcpl, 0, NAME_BUF_SIZE, name, NULL, NULL);
+ name[NAME_BUF_SIZE - 1] = '\0';
+ printf("%s is stored in file: %s\n", DATASET, name);
+
+ /*
+ * Read the data using the default properties.
+ */
+ status = H5Dread(dset, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, rdata[0]);
+
+ /*
+ * Output the data to the screen.
+ */
+ printf("%s:\n", DATASET);
+ for (i = 0; i < DIM0; i++) {
+ printf(" [");
+ for (j = 0; j < DIM1; j++)
+ printf(" %3d", rdata[i][j]);
+ printf("]\n");
+ }
+
+ /*
+ * Close and release resources.
+ */
+ status = H5Pclose(dcpl);
+ status = H5Dclose(dset);
+ status = H5Fclose(file);
+
+ return 0;
+}