<html><head><title> HDF5 Draft API Example Code </title></head><body> <center> <h1>HDF5: API Example Code</h1> </center> <P>Example programs/sections of code below: <dl COMPACT> <dt><a href="#Example1">#1</a> <dd>A simple example showing how to create a file. <dt><a href="#Example2">#2</a> <dd>A example showing how to create a homogenous multi-dimensional dataset. <dt><a href="#Example3">#3</a> <dd>A example showing how to read a generic dataset. </dl> <hr> <h2><a name="Example1">Simple Example showing how to create a file.</a></h2> <P>Notes:<br> This example creates a new HDF5 file and allows write access. If the file exists already, the H5F_ACC_TRUNC flag would also be necessary to overwrite the previous file's information. <P>Code: <code> <pre> hid_t file_id; file_id=<A HREF="H5.apiv2.html#File-Create">H5Fcreate</a>("example1.h5",H5F_ACC_EXCL,H5P_DEFAULT_TEMPLATE,H5P_DEFAULT_TEMPLATE); <A HREF="H5.apiv2.html#File-Close">H5Fclose</a>(file_id); </pre> </code> <hr> <h2><a name="Example2">Example showing how create a homogenous multi-dimensional dataset.</a></h2> <P>Notes:<br> This example creates a 4-dimensional dataset of 32-bit floating-point numbers, corresponding to the current Scientific Dataset functionality. <P>Code: <code> <pre> 1 hid_t file_id; /* new file's ID */ 2 hid_t dim_id; /* new dimensionality's ID */ 3 int rank=4; /* the number of dimensions */ 4 hsize_t dims[4]={6,5,4,3}; /* the size of each dimension */ 5 hid_t dataset_id; /* new dataset's ID */ 6 float buf[6][5][4][3]; /* storage for the dataset's data */ 7 herr_t status; /* function return status */ 8 9 file_id = H5Fcreate ("example3.h5", H5F_ACC_TRUNC, H5P_DEFAULT, 10 H5P_DEFAULT); 11 assert (file_id >= 0); 12 13 /* Create & initialize a dimensionality object */ 14 dim_id = H5Screate_simple (rank, dims); 15 assert (dim_id >= 0); 16 17 /* Create & initialize the dataset object */ 18 dataset_id = H5Dcreate (file_id, "Simple Object", H5T_NATIVE_FLOAT, 19 dim_id, H5P_DEFAULT); 20 assert (dataset_id >= 0); 21 22 <initialize data array> 23 24 /* Write the entire dataset out */ 25 status = H5Dwrite (dataset_id, H5T_NATIVE_FLOAT, H5S_ALL, H5S_ALL, 26 H5P_DEFAULT, buf); 27 assert (status >= 0); 28 29 /* Release the IDs we've created */ 30 H5Sclose (dim_id); 31 H5Dclose (dataset_id); 32 H5Fclose (file_id); </pre> </code> <hr> <h2><a name="Example3">Example showing how read a generic dataset.</a></h2> <P>Notes:<br> This example shows how to get the information for and display a generic dataset. <P>Code: <code> <pre> 1 hid_t file_id; /* file's ID */ 2 hid_t dataset_id; /* dataset's ID in memory */ 3 hid_t space_id; /* dataspace's ID in memory */ 4 uintn nelems; /* number of elements in array */ 5 double *buf; /* pointer to the dataset's data */ 6 herr_t status; /* function return value */ 7 8 file_id = H5Fopen ("example6.h5", H5F_ACC_RDONLY, H5P_DEFAULT); 9 assert (file_id >= 0); 10 11 /* Attach to a datatype object */ 12 dataset_id = H5Dopen (file_id, "dataset1"); 13 assert (dataset_id >= 0); 14 15 /* Get the OID for the dataspace */ 16 space_id = H5Dget_space (dataset_id); 17 assert (space_id >= 0); 18 19 /* Allocate space for the data */ 20 nelems = H5Sget_npoints (space_id); 21 buf = malloc (nelems * sizeof(double)); 22 23 /* Read in the dataset */ 24 status = H5Dread (dataset_id, H5T_NATIVE_DOUBLE, H5S_ALL,, H5S_ALL, 25 H5P_DEFAULT, buf); 26 assert (status >= 0); 27 28 /* Release the IDs we've accessed */ 29 H5Sclose (space_id); 30 H5Dclose (dataset_id); 31 H5Fclose (file_id); </pre> </code>