hdf5/HDF5Examples/C/H5D/h5ex_d_extern.c
Allen Byrne fc88fcde10
Develop merge examples (#3851)
* Merge examples repo into library

* Change grepTest to be more fault-tolerant

* Update examples macro file

* Exclude all Fortran examples from doxygen
2023-11-27 15:30:15 -06:00

129 lines
3.4 KiB
C

/************************************************************
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.
************************************************************/
#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 = H5I_INVALID_HID;
hid_t space = H5I_INVALID_HID;
hid_t dset = H5I_INVALID_HID;
hid_t dcpl = H5I_INVALID_HID;
herr_t status;
hsize_t dims[2] = {DIM0, DIM1};
char name[NAME_BUF_SIZE];
int wdata[DIM0][DIM1]; /* Write buffer */
int rdata[DIM0][DIM1]; /* Read buffer */
hsize_t 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, H5P_DEFAULT, dcpl, H5P_DEFAULT);
/*
* 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, H5P_DEFAULT);
/*
* 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;
}