diff options
Diffstat (limited to 'doxygen/examples/H5O_examples.c')
| -rw-r--r-- | doxygen/examples/H5O_examples.c | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/doxygen/examples/H5O_examples.c b/doxygen/examples/H5O_examples.c new file mode 100644 index 0000000..296acd1 --- /dev/null +++ b/doxygen/examples/H5O_examples.c @@ -0,0 +1,193 @@ +/* -*- c-file-style: "stroustrup" -*- */ + +#include "hdf5.h" + +#include <stdio.h> +#include <stdlib.h> + +#define H5P_DEFAULTx2 H5P_DEFAULT, H5P_DEFAULT + +int +main(void) +{ + int ret_val = EXIT_SUCCESS; + + //! <!-- [create] --> + { + __label__ fail_file; + hid_t file, group; + char src_path[] = "/a/few/groups"; + + if ((file = H5Fcreate("o1.h5", H5F_ACC_TRUNC, H5P_DEFAULTx2)) == H5I_INVALID_HID) { + ret_val = EXIT_FAILURE; + goto fail_file; + } + + // create a few groups + { + __label__ fail_group, fail_lcpl; + hid_t lcpl; + if ((lcpl = H5Pcreate(H5P_LINK_CREATE)) == H5I_INVALID_HID) { + ret_val = EXIT_FAILURE; + goto fail_lcpl; + } + if (H5Pset_create_intermediate_group(lcpl, 1) < 0) { + ret_val = EXIT_FAILURE; + goto fail_group; + } + if ((group = H5Gcreate(file, src_path, lcpl, H5P_DEFAULTx2)) == H5I_INVALID_HID) { + ret_val = EXIT_FAILURE; + goto fail_group; + } + + H5Gclose(group); +fail_group: + H5Pclose(lcpl); +fail_lcpl:; + } + + // create a copy + if (H5Ocopy(file, ".", file, "copy of", H5P_DEFAULTx2) < 0) { + ret_val = EXIT_FAILURE; + } + + H5Fclose(file); +fail_file:; + } + //! <!-- [create] --> + + //! <!-- [read] --> + { + __label__ fail_info, fail_file; + hid_t file; + char path[] = "/a/few/groups"; + H5O_info2_t info; + + if ((file = H5Fopen("o1.h5", H5F_ACC_RDONLY, H5P_DEFAULT)) == H5I_INVALID_HID) { + ret_val = EXIT_FAILURE; + goto fail_file; + } + + // retrieve information about the object + if (H5Oget_info_by_name(file, path, &info, H5O_INFO_BASIC | H5O_INFO_NUM_ATTRS, H5P_DEFAULT) < 0) { + ret_val = EXIT_FAILURE; + goto fail_info; + } + + // determine the object type + switch (info.type) { + case H5O_TYPE_GROUP: + printf("HDF5 group\n"); + break; + case H5O_TYPE_DATASET: + printf("HDF5 dataset\n"); + break; + case H5O_TYPE_NAMED_DATATYPE: + printf("HDF5 datatype\n"); + break; + default: + printf("UFO?\n"); + break; + } + // print basic information + printf("Reference count: %u\n", info.rc); + printf("Attribute count: %lld\n", info.num_attrs); + +fail_info: + H5Fclose(file); +fail_file:; + } + //! <!-- [read] --> + + //! <!-- [update] --> + { + __label__ fail_obj, fail_incr, fail_file; + hid_t file, obj; + char path[] = "/a/few/groups"; + H5O_info2_t info; + + if ((file = H5Fopen("o1.h5", H5F_ACC_RDWR, H5P_DEFAULT)) == H5I_INVALID_HID) { + ret_val = EXIT_FAILURE; + goto fail_file; + } + + // open an object by path name + if ((obj = H5Oopen(file, path, H5P_DEFAULT)) == H5I_INVALID_HID) { + ret_val = EXIT_FAILURE; + goto fail_obj; + } + + // bump its reference count (by 1) + if (H5Oincr_refcount(obj) < 0) { + ret_val = EXIT_FAILURE; + goto fail_incr; + } + + // confirm the new reference count + if (H5Oget_info(obj, &info, H5O_INFO_BASIC) < 0) { + ret_val = EXIT_FAILURE; + goto fail_incr; + } + printf("Reference count: %u\n", info.rc); + +fail_incr: + H5Oclose(obj); +fail_obj: + H5Fclose(file); +fail_file:; + } + //! <!-- [update] --> + + //! <!-- [delete] --> + { + __label__ fail_obj, fail_delete, fail_file; + hid_t file, obj; + char path[] = "/a/few/groups"; + H5O_info2_t info; + + if ((file = H5Fopen("o1.h5", H5F_ACC_RDWR, H5P_DEFAULT)) == H5I_INVALID_HID) { + ret_val = EXIT_FAILURE; + goto fail_file; + } + + // open an object by path name + if ((obj = H5Oopen(file, path, H5P_DEFAULT)) == H5I_INVALID_HID) { + ret_val = EXIT_FAILURE; + goto fail_obj; + } + + // render it inaccessible from the root group by deleting the one and + // only link to it; this drops the reference count by 1 + if (H5Ldelete(file, path, H5P_DEFAULT) < 0) { + ret_val = EXIT_FAILURE; + goto fail_delete; + } + + // confirm the new reference count + if (H5Oget_info(obj, &info, H5O_INFO_BASIC) < 0) { + ret_val = EXIT_FAILURE; + goto fail_delete; + } + printf("Reference count: %u\n", info.rc); + + // if we close the file at this point, we'd be creating a tombstone, + // an object that cannot be reached and that cannot be reclaimed by the + // freespace manager; decrement the reference count to zero to prevent that + if (H5Idec_ref(obj) < 0) { + ret_val = EXIT_FAILURE; + goto fail_delete; + } + else + // attempting to close the object would be like a double H5Oclose and fail + goto fail_obj; + +fail_delete: + H5Oclose(obj); +fail_obj: + H5Fclose(file); +fail_file:; + } + //! <!-- [delete] --> + + return ret_val; +} |