Hi Ed,
> Do me a favor, compile and run this program.
Sure, I'll let you know in a few minutes what my prognosis is... :-)
Quincey
> When I chage this program to use a contiguous dataset, and take out
> the H5Dextend call, everything works. But using an extendable dataset,
> it give me a seg fault.
>
> Obviously I'm doing something wrong with respect to my setting up or
> using the chunked dataset. I'm going to reread the docs and see what
> they say again...
>
> Ed
>
>
> /*
> Why doesn't this work?
> */
>
> #include <hdf5.h>
>
> int main(void);
>
> #define BAIL(e) do { \
> printf("Bailing out in file %s, line %d, error:%d.\n", __FILE__, __LINE__,
> e); \
> goto exit; \
> } while (0)
>
> #define DATASET_NAME "eds_ds"
>
> int
> main()
> {
> hid_t hdfid = 0, datasetid = 0, plistid = 0, type = 0;
> hid_t mem_space = 0, file_space = 0;
> float data = 99.9;
> hssize_t ndata;
> hssize_t coord[1][1];
> int retval = 0;
>
> /* Create a file. */
> if ((hdfid = H5Fcreate("aaa_test.h5", H5F_ACC_TRUNC, H5P_DEFAULT,
> H5P_DEFAULT)) < 0)
> BAIL(-1);
>
> /* Store floats. */
> if ((type = H5Tcopy(H5T_NATIVE_FLOAT)) < 0)
> BAIL(-2);
>
> /* Reading and writing to memory always happens one element at a
> time. */
> {
> hsize_t dimsize1[] = {1};
> if ((mem_space = H5Screate_simple(1, dimsize1, NULL)) < 0)
> BAIL(-3);
> }
>
> /* Crate an extendable dataset, of rank 1, with 1 datum in it. */
> {
> hsize_t maxdim = H5S_UNLIMITED, start_ndata = 1, chunk_size = 1;
> if ((file_space = H5Screate_simple(1, &start_ndata, &maxdim)) < 0)
> BAIL(-4);
> if ((plistid = H5Pcreate(H5P_DATASET_CREATE)) < 0)
> BAIL(-4);
> if (H5Pset_chunk(plistid, 1, &chunk_size) < 0)
> BAIL(-4);
> if ((datasetid = H5Dcreate(hdfid, DATASET_NAME,
> type, file_space, plistid)) < 0)
> BAIL(-4);
> }
>
> /* Write one value. */
> if ((file_space = H5Dget_space(datasetid)) < 0)
> BAIL(-4);
> ndata = H5Sget_simple_extent_npoints(file_space);
> printf("number of data in dataset: %d\n", (int)ndata);
> coord[0][0] = 0;
> if (H5Sselect_elements(file_space, H5S_SELECT_SET, 1,
> (const hssize_t **)coord) < 0)
> BAIL(-4);
> if (H5Dwrite(datasetid, type, mem_space, file_space,
> H5P_DEFAULT, &data) < 0)
> BAIL(-4);
> H5Dclose(datasetid);
> datasetid = 0;
>
> /* Read the value just written. */
> {
> float thefloat;
>
> if ((datasetid = H5Dopen(hdfid, DATASET_NAME)) < 0)
> BAIL(-3);
> if ((file_space = H5Dget_space(datasetid)) < 0)
> BAIL(-3);
> ndata = H5Sget_simple_extent_npoints(file_space);
> printf("number of data in dataset: %d\n", (int)ndata);
> coord[0][0] = 0;
> if (H5Sselect_elements(file_space, H5S_SELECT_SET, 1,
> (const hssize_t **)coord) < 0)
> BAIL(-4);
> if (H5Dread(datasetid, type, mem_space, file_space,
> H5P_DEFAULT, &thefloat) < 0)
> BAIL(-3);
> printf("the float: %f\n", thefloat);
> H5Dclose(datasetid);
> datasetid = 0;
> }
>
> /* Add another datum. */
> {
> hsize_t extend_size = 2;
> float secfloat = 88.8;
> if ((datasetid = H5Dopen(hdfid, DATASET_NAME)) < 0)
> BAIL(-3);
> if (H5Dextend(datasetid, &extend_size) < 0)
> BAIL(-10);
> if ((file_space = H5Dget_space(datasetid)) < 0)
> BAIL(-4);
> ndata = H5Sget_simple_extent_npoints(file_space);
> printf("number of data in dataset: %d\n", (int)ndata);
> coord[0][0] = 1;
> if (H5Sselect_elements(file_space, H5S_SELECT_SET, 1,
> (const hssize_t **)coord) < 0)
> BAIL(-4);
> if (H5Dwrite(datasetid, type, mem_space, file_space,
> H5P_DEFAULT, &secfloat) < 0)
> BAIL(-4);
> H5Dclose(datasetid);
> datasetid = 0;
> }
>
> /* Read the value just written. */
> {
> float thefloat;
>
> if ((datasetid = H5Dopen(hdfid, DATASET_NAME)) < 0)
> BAIL(-3);
> if ((file_space = H5Dget_space(datasetid)) < 0)
> BAIL(-3);
> ndata = H5Sget_simple_extent_npoints(file_space);
> printf("number of data in dataset: %d\n", (int)ndata);
> coord[0][0] = 1;
> if (H5Sselect_elements(file_space, H5S_SELECT_SET, 1,
> (const hssize_t **)coord) < 0)
> BAIL(-4);
> if (H5Dread(datasetid, type, mem_space, file_space,
> H5P_DEFAULT, &thefloat) < 0)
> BAIL(-3);
> printf("the float: %f\n", thefloat);
> H5Dclose(datasetid);
> datasetid = 0;
> }
>
> exit:
> if (datasetid > 0) H5Dclose(datasetid);
> if (type > 0) H5Tclose(type);
> if (mem_space > 0) H5Sclose(mem_space);
> if (file_space > 0) H5Sclose(file_space);
> if (plistid > 0) H5Pclose(plistid);
> return retval;
> }
>
