1 files changed, 89 insertions, 0 deletions
diff --git a/HDF5Examples/C/Perf/h5efc.c b/HDF5Examples/C/Perf/h5efc.c
new file mode 100644
index 0000000..8e50c1d
--- /dev/null
+++ b/HDF5Examples/C/Perf/h5efc.c
@@ -0,0 +1,89 @@
+/************************************************************
+
+  This example shows how to use the external file cache.
+
+  This file is intended for use with HDF5 Library version
+  1.8.7 or newer
+
+ ************************************************************/
+
+#include "hdf5.h"
+
+#define FILE      "h5efc.h5"
+#define EXT_FILE1 "h5efc1.h5"
+#define EXT_FILE2 "h5efc2.h5"
+#define EXT_FILE3 "h5efc3.h5"
+
+int
+main(void)
+{
+    hid_t  file1, file2, group, fapl; /* Handles */
+    herr_t status;
+
+    /*
+     * Create file access property list and set it to allow caching of open
+     * files visited through external links.
+     */
+    fapl   = H5Pcreate(H5P_FILE_ACCESS);
+    status = H5Pset_elink_file_cache_size(fapl, 8);
+
+    /*
+     * Create a new file using the file access property list.
+     */
+    file1 = H5Fcreate(FILE, H5F_ACC_TRUNC, H5P_DEFAULT, fapl);
+
+    /*
+     * Create files to serve as targets for external links.
+     */
+    file2  = H5Fcreate(EXT_FILE1, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    status = H5Fclose(file2);
+    file2  = H5Fcreate(EXT_FILE2, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    status = H5Fclose(file2);
+    file2  = H5Fcreate(EXT_FILE3, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
+    status = H5Fclose(file2);
+
+    /*
+     * Create external links to the target files.
+     */
+    status = H5Lcreate_external(EXT_FILE1, "/", file1, "link_to_1", H5P_DEFAULT, H5P_DEFAULT);
+    status = H5Lcreate_external(EXT_FILE2, "/", file1, "link_to_2", H5P_DEFAULT, H5P_DEFAULT);
+    status = H5Lcreate_external(EXT_FILE3, "/", file1, "link_to_3", H5P_DEFAULT, H5P_DEFAULT);
+
+    /*
+     * Open and close the targets of all three external links (these will be the
+     * root groups of the target files).  The target files should be held open
+     * by the root file's external file cache after traversal.
+     */
+    group  = H5Gopen(file1, "/link_to_1", H5P_DEFAULT);
+    status = H5Gclose(group);
+    group  = H5Gopen(file1, "/link_to_2", H5P_DEFAULT);
+    status = H5Gclose(group);
+    group  = H5Gopen(file1, "/link_to_3", H5P_DEFAULT);
+    status = H5Gclose(group);
+
+    /*
+     * Open and close the targets of all three external links again.  The target
+     * files should already be held open by the root file's external file cache,
+     * so the library will not actually have to issue an "open" system call.
+     */
+    group  = H5Gopen(file1, "/link_to_1", H5P_DEFAULT);
+    status = H5Gclose(group);
+    group  = H5Gopen(file1, "/link_to_2", H5P_DEFAULT);
+    status = H5Gclose(group);
+    group  = H5Gopen(file1, "/link_to_3", H5P_DEFAULT);
+    status = H5Gclose(group);
+
+    /*
+     * Release the root file's external file cache.  This will close all the
+     * external link target files.
+     */
+    status = H5Frelease_file_cache(file1);
+
+    /*
+     * Close and release resources.
+     */
+    status = H5Pclose(fapl);
+    status = H5Fclose(file1);
+
+    return 0;
+}