summaryrefslogtreecommitdiffstats
path: root/HDF5Examples/C/H5T/16/h5ex_t_objref.c
diff options
context:
space:
mode:
Diffstat (limited to 'HDF5Examples/C/H5T/16/h5ex_t_objref.c')
-rw-r--r--HDF5Examples/C/H5T/16/h5ex_t_objref.c158
1 files changed, 158 insertions, 0 deletions
diff --git a/HDF5Examples/C/H5T/16/h5ex_t_objref.c b/HDF5Examples/C/H5T/16/h5ex_t_objref.c
new file mode 100644
index 0000000..4c35239
--- /dev/null
+++ b/HDF5Examples/C/H5T/16/h5ex_t_objref.c
@@ -0,0 +1,158 @@
+/************************************************************
+
+ This example shows how to read and write object references
+ to a dataset. The program first creates objects in the
+ file and writes references to those objects to a dataset
+ with a dataspace of DIM0, then closes the file. Next, it
+ reopens the file, dereferences the references, and outputs
+ the names of their targets 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_t_objref.h5"
+#define DATASET "DS1"
+#define DIM0 2
+
+int
+main(void)
+{
+ hid_t file, space, dset, obj; /* Handles */
+ herr_t status;
+ hsize_t dims[1] = {DIM0};
+ hobj_ref_t wdata[DIM0], /* Write buffer */
+ *rdata; /* Read buffer */
+ H5G_obj_t objtype;
+ ssize_t size;
+ char *name;
+ int ndims, i;
+
+ /*
+ * Create a new file using the default properties.
+ */
+ file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+
+ /*
+ * Create a dataset with a scalar dataspace.
+ */
+ space = H5Screate(H5S_SCALAR);
+ obj = H5Dcreate(file, "DS2", H5T_STD_I32LE, space, H5P_DEFAULT);
+ status = H5Dclose(obj);
+ status = H5Sclose(space);
+
+ /*
+ * Create a group.
+ */
+ obj = H5Gcreate(file, "G1", H5P_DEFAULT);
+ status = H5Gclose(obj);
+
+ /*
+ * Create references to the previously created objects. Passing -1
+ * as space_id causes this parameter to be ignored. Other values
+ * besides valid dataspaces result in an error.
+ */
+ status = H5Rcreate(&wdata[0], file, "G1", H5R_OBJECT, -1);
+ status = H5Rcreate(&wdata[1], file, "DS2", H5R_OBJECT, -1);
+
+ /*
+ * Create dataspace. Setting maximum size to NULL sets the maximum
+ * size to be the current size.
+ */
+ space = H5Screate_simple(1, dims, NULL);
+
+ /*
+ * Create the dataset and write the object references to it.
+ */
+ dset = H5Dcreate(file, DATASET, H5T_STD_REF_OBJ, space, H5P_DEFAULT);
+ status = H5Dwrite(dset, H5T_STD_REF_OBJ, H5S_ALL, H5S_ALL, H5P_DEFAULT, wdata);
+
+ /*
+ * Close and release resources.
+ */
+ status = H5Dclose(dset);
+ status = H5Sclose(space);
+ status = H5Fclose(file);
+
+ /*
+ * Now we begin the read section of this example. Here we assume
+ * the dataset has the same name and rank, but can have any size.
+ * Therefore we must allocate a new array to read in data using
+ * malloc().
+ */
+
+ /*
+ * Open file and dataset.
+ */
+ file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT);
+ dset = H5Dopen(file, DATASET);
+
+ /*
+ * Get dataspace and allocate memory for read buffer.
+ */
+ space = H5Dget_space(dset);
+ ndims = H5Sget_simple_extent_dims(space, dims, NULL);
+ rdata = (hobj_ref_t *)malloc(dims[0] * sizeof(hobj_ref_t));
+
+ /*
+ * Read the data.
+ */
+ status = H5Dread(dset, H5T_STD_REF_OBJ, H5S_ALL, H5S_ALL, H5P_DEFAULT, rdata);
+
+ /*
+ * Output the data to the screen.
+ */
+ for (i = 0; i < dims[0]; i++) {
+ printf("%s[%d]:\n ->", DATASET, i);
+ /*
+ * Open the referenced object, get its name and type.
+ */
+ obj = H5Rdereference(dset, H5R_OBJECT, &rdata[i]);
+ objtype = H5Rget_obj_type(dset, H5R_OBJECT, &rdata[i]);
+
+ /*
+ * Get the length of the name, allocate space, then retrieve
+ * the name.
+ */
+ size = 1 + H5Iget_name(obj, NULL, 0);
+ name = (char *)malloc(size);
+ size = H5Iget_name(obj, name, size);
+
+ /*
+ * Print the object type and close the object.
+ */
+ switch (objtype) {
+ case H5G_GROUP:
+ printf("Group");
+ status = H5Gclose(obj);
+ break;
+ case H5G_DATASET:
+ printf("Dataset");
+ status = H5Dclose(obj);
+ break;
+ case H5G_TYPE:
+ printf("Named Datatype");
+ status = H5Tclose(obj);
+ }
+
+ /*
+ * Print the name and deallocate space for the name.
+ */
+ printf(": %s\n", name);
+ free(name);
+ }
+
+ /*
+ * Close and release resources.
+ */
+ free(rdata);
+ status = H5Dclose(dset);
+ status = H5Sclose(space);
+ status = H5Fclose(file);
+
+ return 0;
+}