/************************************************************

  This example shows how to commit a named datatype to a
  file, and read back that datatype.  The program first
  defines a compound datatype, commits it to a file, then
  closes the file.  Next, it reopens the file, opens the
  datatype, and outputs the names of its fields to the
  screen.

 ************************************************************/

#include "hdf5.h"
#include <stdio.h>
#include <stdlib.h>

#define FILE     "h5ex_t_commit.h5"
#define DATATYPE "Sensor_Type"

int
main(void)
{
    hid_t file, filetype, strtype;
    /* Handles */
    herr_t      status;
    H5T_class_t typeclass;
    char       *name;
    int         nmembs, i;

    /*
     * Create a new file using the default properties.
     */
    file = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);

    /*
     * Create variable-length string datatype.
     */
    strtype = H5Tcopy(H5T_C_S1);
    status  = H5Tset_size(strtype, H5T_VARIABLE);

    /*
     * Create the compound datatype.  Because the standard types we are
     * using may have different sizes than the corresponding native
     * types, we must manually calculate the offset of each member.
     */
    filetype = H5Tcreate(H5T_COMPOUND, 8 + sizeof(char *) + 8 + 8);
    status   = H5Tinsert(filetype, "Serial number", 0, H5T_STD_I64BE);
    status   = H5Tinsert(filetype, "Location", 8, strtype);
    status   = H5Tinsert(filetype, "Temperature (F)", 8 + sizeof(char *), H5T_IEEE_F64BE);
    status   = H5Tinsert(filetype, "Pressure (inHg)", 8 + sizeof(char *) + 8, H5T_IEEE_F64BE);

    /*
     * Commit the compound datatype to the file, creating a named
     * datatype.
     */
    status = H5Tcommit(file, DATATYPE, filetype, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);

    /*
     * Close and release resources.
     */
    status = H5Tclose(filetype);
    status = H5Tclose(strtype);
    status = H5Fclose(file);

    /*
     * Now we begin the read section of this example.
     */

    /*
     * Open file.
     */
    file = H5Fopen(FILE, H5F_ACC_RDONLY, H5P_DEFAULT);

    /*
     * Open the named datatype.
     */
    filetype = H5Topen(file, DATATYPE, H5P_DEFAULT);

    /*
     * Output the data to the screen.
     */
    printf("Named datatype: %s:\n", DATATYPE);
    /*
     * Get datatype class.  If it isn't compound, we won't print
     * anything.
     */
    typeclass = H5Tget_class(filetype);
    if (typeclass == H5T_COMPOUND) {
        printf("   Class: H5T_COMPOUND\n");
        nmembs = H5Tget_nmembers(filetype);
        /*
         * Iterate over compound datatype members.
         */
        for (i = 0; i < nmembs; i++) {
            /*
             * Get the member name and print it.  Note that
             * H5Tget_member_name allocates space for the string in
             * name, so we must release it after use.
             */
            name = H5Tget_member_name(filetype, i);
            printf("   %s\n", name);
#if H5_VERSION_GE(1, 10, 0) && !defined(H5_USE_18_API) && !defined(H5_USE_16_API)
            H5free_memory(name);
#else
            free(name);
#endif
        }
    }

    /*
     * Close and release resources.
     */
    status = H5Tclose(filetype);
    status = H5Fclose(file);

    return 0;
}