Merge pull request #621 in HDFFV/hdf5 from ~DEROBINS/hdf5_der:h5pl_commit to develop

* commit '9bcf8b2f2568083449ae3f9b6c2efbf6ed7f413a':
  Minor tweaks in response to code review.
  Fixed a failing Java plugin test.
  Major rework of H5PL package code before bringing VOL changes over.

17 files changed, 2235 insertions, 1015 deletions

diff --git a/MANIFEST b/MANIFEST
index e5a038d..c7729e8 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -799,8 +799,11 @@
 ./src/H5PBpkg.h
 ./src/H5PBprivate.h
 ./src/H5PL.c
+./src/H5PLint.c
 ./src/H5PLmodule.h
+./src/H5PLpath.c
 ./src/H5PLpkg.h
+./src/H5PLplugin_cache.c
 ./src/H5PLprivate.h
 ./src/H5PLpublic.h
 ./src/H5PLextern.h
diff --git a/bin/trace b/bin/trace
index 3f532ab..cf41238 100755
--- a/bin/trace
+++ b/bin/trace
@@ -76,7 +76,7 @@ $Source = "";
                "off_t"                      => "o",
                "H5O_type_t"                 => "Ot",
                "H5P_class_t"                => "p",
-               "hobj_ref_t"		    => "r",
+               "hobj_ref_t"                 => "r",
                "H5R_type_t"                 => "Rt",
                "char"                       => "s",
                "unsigned char"              => "s",
@@ -124,7 +124,7 @@ $Source = "";
                "H5G_iterate_t"              => "x",
                "H5G_info_t"                 => "x",
                "H5I_free_t"                 => "x",
-               "H5I_search_func_t"         => "x",
+               "H5I_search_func_t"          => "x",
                "H5L_class_t"                => "x",
                "H5L_elink_traverse_t"       => "x",
                "H5L_iterate_t"              => "x",
diff --git a/java/test/TestH5PL.java b/java/test/TestH5PL.java
index aa59478..8ce708b 100644
--- a/java/test/TestH5PL.java
+++ b/java/test/TestH5PL.java
@@ -70,26 +70,74 @@ public class TestH5PL {
     @Test
     public void TestH5PLpaths() {
         try {
-            int original_entries = H5.H5PLsize();
-            H5.H5PLappend("path_one");
-            int plugin_entries = H5.H5PLsize();
-            assertTrue("H5.H5PLsize: "+plugin_entries, (original_entries+1) == plugin_entries);
-            H5.H5PLprepend("path_two");
-            plugin_entries = H5.H5PLsize();
-            assertTrue("H5.H5PLsize: "+plugin_entries, (original_entries+2) == plugin_entries);
-            H5.H5PLinsert("path_three", original_entries);
-            plugin_entries = H5.H5PLsize();
-            assertTrue("H5.H5PLsize: "+plugin_entries, (original_entries+3) == plugin_entries);
-            String first_path = H5.H5PLget(original_entries);
-            assertTrue("First path was : "+first_path + " ",first_path.compareToIgnoreCase("path_three")==0);
-            H5.H5PLreplace("path_four", original_entries);
-            first_path = H5.H5PLget(original_entries);
-            assertTrue("First path changed to : "+first_path + " ",first_path.compareToIgnoreCase("path_four")==0);
-            H5.H5PLremove(original_entries);
-            first_path = H5.H5PLget(original_entries);
-            assertTrue("First path now : "+first_path + " ",first_path.compareToIgnoreCase("path_two")==0);
-            plugin_entries = H5.H5PLsize();
-            assertTrue("H5.H5PLsize: "+plugin_entries, (original_entries+2) == plugin_entries);
+            // Get the original number of paths
+            int nStartPaths = H5.H5PLsize();
+
+            int nPaths;                     /* # paths from H5PLSize()      */
+            int nTruePaths = nStartPaths;   /* What the # paths should be   */
+            int index;                      /* Path table index             */
+            String path;                    /* Path from H5PLget()          */
+
+            // APPEND a path and ensure it was added correctly
+            String pathAppend = "path_append";
+            H5.H5PLappend(pathAppend);
+
+            nPaths = H5.H5PLsize();
+            nTruePaths++;
+            assertTrue("# paths should be " + nTruePaths + " but was " + nPaths, nTruePaths == nPaths);
+
+            index = nTruePaths - 1;
+            path = H5.H5PLget(index);
+            assertTrue("Path should be " + pathAppend + " but was " + path, path.compareToIgnoreCase(pathAppend) == 0);
+
+            // PREPEND a path and ensure it was added correctly
+            String pathPrepend = "path_prepend";
+            H5.H5PLprepend(pathPrepend);
+
+            nPaths = H5.H5PLsize();
+            nTruePaths++;
+            assertTrue("# paths should be " + nTruePaths + " but was " + nPaths, nTruePaths == nPaths);
+
+            index = 0;
+            path = H5.H5PLget(index);
+            assertTrue("Path should be " + pathPrepend + " but was " + path, path.compareToIgnoreCase(pathPrepend) == 0);
+
+            // INSERT a path and ensure it was added correctly
+            // Inserting at the index == # of start paths ensures we're in the middle
+            String pathInsert = "path_insert";
+            index = nStartPaths;
+            H5.H5PLinsert(pathInsert, index);
+
+            nPaths = H5.H5PLsize();
+            nTruePaths++;
+            assertTrue("# paths should be " + nTruePaths + " but was " + nPaths, nTruePaths == nPaths);
+
+            path = H5.H5PLget(index);
+            assertTrue("Path should be " + pathInsert + " but was " + path, path.compareToIgnoreCase(pathInsert) == 0);
+
+            // REPLACE the path we just added and ensure it updated correctly
+            String pathReplace = "path_replace";
+            index = nStartPaths;
+            H5.H5PLreplace(pathReplace, index);
+
+            nPaths = H5.H5PLsize();
+            assertTrue("# paths should be " + nTruePaths + " but was " + nPaths, nTruePaths == nPaths);
+
+            path = H5.H5PLget(index);
+            assertTrue("Path should be " + pathReplace + " but was " + path, path.compareToIgnoreCase(pathReplace) == 0);
+
+            // REMOVE the path we just replaced and check that the table was compacted
+            // The (index+1) path should move down to fill the space when the path is removed.
+            index = nStartPaths;
+            String pathRemove = H5.H5PLget(index + 1);
+            H5.H5PLremove(index);
+
+            nPaths = H5.H5PLsize();
+            nTruePaths--;
+            assertTrue("# paths should be " + nTruePaths + " but was " + nPaths, nTruePaths == nPaths);
+
+            path = H5.H5PLget(index);
+            assertTrue("Path should be " + pathRemove + " but was " + path, path.compareToIgnoreCase(pathRemove) == 0);
         }
         catch (Throwable err) {
             err.printStackTrace();
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 178c954..96ea589 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -516,6 +516,9 @@ IDE_GENERATED_PROPERTIES ("H5PB" "${H5PB_HDRS}" "${H5PB_SOURCES}" )
 
 set (H5PL_SOURCES
     ${HDF5_SRC_DIR}/H5PL.c
+    ${HDF5_SRC_DIR}/H5PLint.c
+    ${HDF5_SRC_DIR}/H5PLpath.c
+    ${HDF5_SRC_DIR}/H5PLplugin_cache.c
 )
 
 set (H5PL_HDRS
diff --git a/src/H5PL.c b/src/H5PL.c
index 65d6c91..fc42554 100644
--- a/src/H5PL.c
+++ b/src/H5PL.c
@@ -22,135 +22,28 @@
 /***********/
 #include "H5private.h"      /* Generic Functions            */
 #include "H5Eprivate.h"     /* Error handling               */
-#include "H5MMprivate.h"    /* Memory management            */
 #include "H5PLpkg.h"        /* Plugin                       */
-#include "H5Zprivate.h"     /* Filter pipeline              */
 
 
 /****************/
 /* Local Macros */
 /****************/
-#ifdef H5_HAVE_WIN32_API
-#define H5PL_EXPAND_ENV_VAR {                                                            \
-        long bufCharCount;                                                               \
-        char *tempbuf;                                                                   \
-        if(NULL == (tempbuf = (char *)H5MM_malloc(H5PL_EXPAND_BUFFER_SIZE)))             \
-            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for expanded path")                          \
-        if((bufCharCount = ExpandEnvironmentStringsA(dl_path, tempbuf, H5PL_EXPAND_BUFFER_SIZE)) > H5PL_EXPAND_BUFFER_SIZE) { \
-            tempbuf = (char *)H5MM_xfree(tempbuf);                                       \
-            HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "expanded path is too long")      \
-        }                                                                                \
-        if(bufCharCount == 0) {                                                          \
-            tempbuf = (char *)H5MM_xfree(tempbuf);                                       \
-            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "failed to expand path")          \
-        }                                                                                \
-        dl_path = (char *)H5MM_xfree(dl_path);                                           \
-        dl_path = tempbuf;                                                               \
- }
-#else
-#define H5PL_EXPAND_ENV_VAR
-#endif /* H5_HAVE_WIN32_API */
-
-/****************************/
-/* Macros for supporting
- * both Windows and Unix */
-/****************************/
-/* Windows support
- *
- * SPECIAL WINDOWS NOTE
- *
- * Some of the Win32 API functions expand to fooA or fooW depending on
- * whether UNICODE or _UNICODE are defined. You MUST explicitly use
- * the A version of the functions to force char * behavior until we
- * work out a scheme for proper Windows Unicode support.
- *
- * If you do not do this, people will be unable to incorporate our
- * source code into their own CMake builds if they define UNICODE.
- */
-#ifdef H5_HAVE_WIN32_API
-
-#define H5PL_PATH_SEPARATOR     ";"
-
-/* Handle for dynamic library */
-#define H5PL_HANDLE HINSTANCE
-
-/* Get a handle to a plugin library.  Windows: TEXT macro handles Unicode strings */
-#define H5PL_OPEN_DLIB(S) LoadLibraryExA(S, NULL, LOAD_WITH_ALTERED_SEARCH_PATH)
-
-/* Get the address of a symbol in dynamic library */
-#define H5PL_GET_LIB_FUNC(H,N) GetProcAddress(H,N)
-
-/* Close dynamic library */
-#define H5PL_CLOSE_LIB(H) FreeLibrary(H)
-
-/* Clear error - nothing to do */
-#define H5PL_CLR_ERROR
-
-/* maximum size for expanding env vars */
-#define H5PL_EXPAND_BUFFER_SIZE 32767
-
-typedef const void *(__cdecl *H5PL_get_plugin_info_t)(void);
-
-/* Unix support */
-#else /* H5_HAVE_WIN32_API */
-
-#define H5PL_PATH_SEPARATOR     ":"
-
-/* Handle for dynamic library */
-#define H5PL_HANDLE void *
-
-/* Get a handle to a plugin library.  Windows: TEXT macro handles Unicode strings */
-#define H5PL_OPEN_DLIB(S) dlopen(S, RTLD_LAZY)
-
-/* Get the address of a symbol in dynamic library */
-#define H5PL_GET_LIB_FUNC(H,N) dlsym(H,N)
-
-/* Close dynamic library */
-#define H5PL_CLOSE_LIB(H) dlclose(H)
-
-/* Clear error */
-#define H5PL_CLR_ERROR HERROR(H5E_PLUGIN, H5E_CANTGET, "can't dlopen:%s", dlerror())
-
-typedef const void *(*H5PL_get_plugin_info_t)(void);
-#endif /* H5_HAVE_WIN32_API */
-
-/* Whether to preload pathnames for plugin libraries */
-#define H5PL_DEFAULT_PATH       H5_DEFAULT_PLUGINDIR
-
-/* Special symbol to indicate no plugin loading */
-#define H5PL_NO_PLUGIN          "::"
 
 
 /******************/
 /* Local Typedefs */
 /******************/
 
-/* Type for the list of info for opened plugin libraries */
-typedef struct H5PL_table_t {
-    H5PL_type_t pl_type;            /* plugin type          */
-    int         pl_id;              /* ID for the plugin    */
-    H5PL_HANDLE handle;             /* plugin handle        */
-} H5PL_table_t;
-
 
 /********************/
 /* Local Prototypes */
 /********************/
 
-static herr_t H5PL__init_path_table(void);
-static htri_t H5PL__find(H5PL_type_t plugin_type, int type_id, char *dir, const void **info);
-static htri_t H5PL__open(H5PL_type_t pl_type, char *libname, int plugin_id, const void **pl_info);
-static htri_t H5PL__search_table(H5PL_type_t plugin_type, int type_id, const void **info);
-static herr_t H5PL__close(H5PL_HANDLE handle);
-
 
 /*********************/
 /* Package Variables */
 /*********************/
 
-/* Package initialization variable */
-hbool_t H5_PKG_INIT_VAR = FALSE;
-
 
 /*****************************/
 /* Library Private Variables */
@@ -161,145 +54,43 @@ hbool_t H5_PKG_INIT_VAR = FALSE;
 /* Local Variables */
 /*******************/
 
-/* Table for opened plugin libraries */
-static size_t           H5PL_table_alloc_g = 0;
-static size_t           H5PL_table_used_g = 0;
-static H5PL_table_t     *H5PL_table_g = NULL;
-
-/* Table of location paths for plugin libraries */
-static char             *H5PL_path_table_g[H5PL_MAX_PATH_NUM];
-static size_t           H5PL_num_paths_g = 0;
-static hbool_t          H5PL_path_found_g = FALSE;
-
-/* Enable all plugin libraries */
-static unsigned int     H5PL_plugin_g = H5PL_ALL_PLUGIN;
-
-
-
-/*--------------------------------------------------------------------------
-NAME
-   H5PL__init_package -- Initialize interface-specific information
-USAGE
-    herr_t H5PL__init_package()
-RETURNS
-    Non-negative on success/Negative on failure
-DESCRIPTION
-    Initializes any interface-specific data or routines.
-
---------------------------------------------------------------------------*/
-herr_t
-H5PL__init_package(void)
-{
-    char        *preload_path;
-
-    FUNC_ENTER_PACKAGE_NOERR
-
-    /* Retrieve pathnames from HDF5_PLUGIN_PRELOAD if the user sets it
-     * to tell the library to load plugin libraries without search.
-     */
-    if(NULL != (preload_path = HDgetenv("HDF5_PLUGIN_PRELOAD")))
-        /* Special symbol "::" means no plugin during data reading. */
-        if(!HDstrcmp(preload_path, H5PL_NO_PLUGIN))
-            H5PL_plugin_g = 0;
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5PL__init_package() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5PL_term_package
- *
- * Purpose:     Terminate the H5PL interface: release all memory, reset all
- *              global variables to initial values. This only happens if all
- *              types have been destroyed from other interfaces.
+ * Function:    H5PLset_loading_state
  *
- * Return:      Success:    Positive if any action was taken that might
- *                          affect some other interface; zero otherwise.
- *              Failure:    Negative.
- *
- * Programmer:  Raymond Lu
- *              20 February 2013
- *
- *-------------------------------------------------------------------------
- */
-int
-H5PL_term_package(void)
-{
-    int  n = 0;
-
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    if(H5_PKG_INIT_VAR) {
-        size_t u;       /* Local index variable */
-
-        /* Close opened dynamic libraries */
-        if(H5PL_table_g) {
-            for(u = 0; u < H5PL_table_used_g; u++)
-                H5PL__close((H5PL_table_g[u]).handle);
-
-            /* Free the table of dynamic libraries */
-            H5PL_table_g = (H5PL_table_t *)H5MM_xfree(H5PL_table_g);
-            H5PL_table_used_g = H5PL_table_alloc_g = 0;
-
-            n++;
-        } /* end if */
-
-        /* Free the table of search paths */
-        if(H5PL_num_paths_g > 0) {
-            for(u = 0; u < H5PL_num_paths_g; u++)
-                if(H5PL_path_table_g[u])
-                    H5PL_path_table_g[u] = (char *)H5MM_xfree(H5PL_path_table_g[u]);
-            H5PL_num_paths_g = 0;
-            H5PL_path_found_g = FALSE;
-
-            n++;
-        } /* end if */
-
-        /* Mark the interface as uninitialized */
-        if(0 == n)
-            H5_PKG_INIT_VAR = FALSE;
-    } /* end if */
-
-    FUNC_LEAVE_NOAPI(n)
-} /* end H5PL_term_package() */
-
-
-/*-------------------------------------------------------------------------
- * Function: H5PLset_loading_state
+ * Purpose:     Control the loading of dynamic plugin types.
  *
- * Purpose: Control the loading of dynamic plugin types.
+ *              The plugin_control_mask parameter is a bitfield that controls
+ *              whether certain classes of plugins (e.g.: filters,
+ *              VOL drivers) will be loaded by the library.
  *
- * This function will not allow plugin types if the pathname from the HDF5_PLUGIN_PRELOAD
- * environment variable is set to the special "::" string.
+ *              plugin bit = 0, will prevent the use of that dynamic plugin type.
+ *              plugin bit = 1, will allow the use of that dynamic plugin type.
  *
- * plugin bit = 0, will prevent the use of that dynamic plugin type.
- * plugin bit = 1, will allow the use of that dynamic plugin type.
+ *              A list of pre-defined masks can be found in H5PLpublic.h.
+ *              Set the mask to 0 to disable all plugins.
  *
- * H5PL_TYPE_FILTER changes just dynamic filters
- * A H5PL_ALL_PLUGIN will enable all dynamic plugin types
- * A zero value will disable all dynamic plugin types
+ *              This function will not allow plugin types if the pathname
+ *              from the HDF5_PLUGIN_PRELOAD environment variable is set to
+ *              the special "::" string.
  *
- * Return: Non-negative or success
+ * Return:      Success:    Non-negative
+ *              Failture:   Negative
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PLset_loading_state(unsigned int plugin_type)
+H5PLset_loading_state(unsigned int plugin_control_mask)
 {
-    char *preload_path;
-    herr_t ret_value = SUCCEED; /* Return value */
+    herr_t  ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE1("e", "Iu", plugin_type);
-
-    /* change the bit value of the requested plugin type(s) */
-    H5PL_plugin_g = plugin_type;
+    H5TRACE1("e", "Iu", plugin_control_mask);
 
-    /* check if special ENV variable is set and disable all plugin types */
-    if(NULL != (preload_path = HDgetenv("HDF5_PLUGIN_PRELOAD")))
-        /* Special symbol "::" means no plugin during data reading. */
-        if(!HDstrcmp(preload_path, H5PL_NO_PLUGIN))
-            H5PL_plugin_g = 0;
+    /* Set the plugin control mask */
+    if(H5PL__set_plugin_control_mask(plugin_control_mask) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_CANTSET, FAIL, "error setting plugin control mask")
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -307,27 +98,35 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function: H5PLget_loading_state
+ * Function:    H5PLget_loading_state
  *
- * Purpose: Query state of the loading of dynamic plugin types.
+ * Purpose:     Get the bitmask that controls whether certain classes
+ *              of plugins (e.g.: filters, VOL drivers) will be loaded
+ *              by the library.
  *
- * This function will return the state of the global flag.
+ *              Zero if all plugin types are disabled
+ *              Negative if all plugin types are enabled
+ *              Positive if one or more of the plugin types are enabled
  *
- * Return: Zero if all plugin types are disabled, negative if all
- * plugin types are enabled, positive if one or more of the plugin types are enabled.
+ * Return:      Success:    Non-negative
+ *              Failture:   Negative
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PLget_loading_state(unsigned int *plugin_type)
+H5PLget_loading_state(unsigned int *plugin_control_mask)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    herr_t ret_value = SUCCEED;     /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE1("e", "*Iu", plugin_type);
+    H5TRACE1("e", "*Iu", plugin_control_mask);
+
+    if (NULL == plugin_control_mask)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_control_mask parameter cannot be NULL")
 
-    if(plugin_type)
-        *plugin_type = H5PL_plugin_g;
+    /* Set the plugin control mask */
+    if(H5PL__get_plugin_control_mask(plugin_control_mask) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_CANTGET, FAIL, "error getting plugin control mask")
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -335,674 +134,282 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5PL_load
- *
- * Purpose:     Given the plugin type and identifier, this function searches
- *              and/or loads a dynamic plugin library first among the already
- *              opened libraries then in the designated location paths.
- *
- * Return:      Non-NULL on success/NULL on failure
- *
- * Programmer:  Raymond Lu
- *              13 February 2013
- *
- *-------------------------------------------------------------------------
- */
-const void *
-H5PL_load(H5PL_type_t type, int id)
-{
-    htri_t      found;               /* Whether the plugin was found */
-    const void  *plugin_info = NULL;
-    const void  *ret_value = NULL;
-
-    FUNC_ENTER_NOAPI(NULL)
-
-    switch(type) {
-        case H5PL_TYPE_FILTER:
-            if((H5PL_plugin_g & H5PL_FILTER_PLUGIN) == 0)
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTLOAD, NULL, "required dynamically loaded plugin filter '%d' is not available", id)
-            break;
-
-        case H5PL_TYPE_ERROR:
-        case H5PL_TYPE_NONE:
-        default:
-            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTLOAD, NULL, "required dynamically loaded plugin '%d' is not valid", id)
-    } /* end switch */
-
-    /* Initialize the location paths for dynamic libraries, if they aren't
-     * already set up.
-     */
-    if(FALSE == H5PL_path_found_g)
-        if(H5PL__init_path_table() < 0)
-            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINIT, NULL, "can't initialize search path table")
-
-    /* Search in the table of already loaded plugin libraries */
-    if((found = H5PL__search_table(type, id, &plugin_info)) < 0)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, NULL, "search in table failed")
-
-    /* If not found, iterate through the path table to find the right dynamic library */
-    if(!found) {
-        size_t       i;                   /* Local index variable */
-
-        for(i = 0; i < H5PL_num_paths_g; i++) {
-            if((found = H5PL__find(type, id, H5PL_path_table_g[i], &plugin_info)) < 0)
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, NULL, "search in paths failed")
-
-            /* Break out if found */
-            if(found) {
-                HDassert(plugin_info);
-                break;
-            } /* end if */
-        } /* end for */
-    } /* end if */
-
-    /* Check if we found the plugin */
-    if(found)
-        ret_value = plugin_info;
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5PL_load() */
-
-
-/*-------------------------------------------------------------------------
- * Function: H5PLappend
+ * Function:    H5PLappend
  *
- * Purpose: Insert a plugin path at the end of the list.
+ * Purpose:     Insert a plugin search path at the end of the list.
  *
- * Return: Non-negative or success.
+ * Return:      Success:    Non-negative
+ *              Failture:   Negative
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PLappend(const char *plugin_path)
+H5PLappend(const char *search_path)
 {
     herr_t ret_value = SUCCEED; /* Return value */
-    char        *dl_path = NULL;
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE1("e", "*s", plugin_path);
-    if(H5PL_num_paths_g == H5PL_MAX_PATH_NUM)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "too many directories in path for table")
-    if(NULL == plugin_path)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "no path provided")
-    if(NULL == (dl_path = H5MM_strdup(plugin_path)))
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
+    H5TRACE1("e", "*s", search_path);
 
-    H5PL_EXPAND_ENV_VAR
+    /* Check args */
+    if (NULL == search_path)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_path parameter cannot be NULL")
+    if (0 == HDstrlen(search_path))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_path parameter cannot have length zero")
 
-    H5PL_path_table_g[H5PL_num_paths_g] = dl_path;
-    H5PL_num_paths_g++;
+    /* Append the search path to the path table */
+    if (H5PL__append_path(search_path) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTAPPEND, FAIL, "unable to append search path")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5PLappend() */
 
-
+
 /*-------------------------------------------------------------------------
- * Function: H5PLprepend
+ * Function:    H5PLprepend
  *
- * Purpose: Insert a plugin path at the beginning of the list.
+ * Purpose:     Insert a plugin search path at the beginning of the list.
  *
- * Return: Non-negative or success.
+ * Return:      Success:    Non-negative
+ *              Failture:   Negative
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PLprepend(const char *plugin_path)
+H5PLprepend(const char *search_path)
 {
     herr_t ret_value = SUCCEED; /* Return value */
-    char        *dl_path = NULL;
-    unsigned int plindex;
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE1("e", "*s", plugin_path);
-    if(H5PL_num_paths_g == H5PL_MAX_PATH_NUM)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "too many directories in path for table")
-    if(NULL == plugin_path)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "no path provided")
-    if(NULL == (dl_path = H5MM_strdup(plugin_path)))
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
+    H5TRACE1("e", "*s", search_path);
 
-    H5PL_EXPAND_ENV_VAR
+    /* Check args */
+    if (NULL == search_path)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_path parameter cannot be NULL")
+    if (0 == HDstrlen(search_path))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_path parameter cannot have length zero")
 
-    for (plindex = (unsigned int)H5PL_num_paths_g; plindex > 0; plindex--)
-        H5PL_path_table_g[plindex] = H5PL_path_table_g[plindex - 1];
-    H5PL_path_table_g[0] = dl_path;
-    H5PL_num_paths_g++;
+    /* Prepend the search path to the path table */
+    if (H5PL__prepend_path(search_path) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINSERT, FAIL, "unable to prepend search path")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5PLprepend() */
 
-
+
 /*-------------------------------------------------------------------------
- * Function: H5PLreplace
+ * Function:    H5PLreplace
  *
- * Purpose: Replace the path at the specified index.
+ * Purpose:     Replace the path at the specified index. The path at the
+ *              index must exist.
  *
- * Return: Non-negative or success.
+ * Return:      Non-negative or success.
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PLreplace(const char *plugin_path, unsigned int index)
+H5PLreplace(const char *search_path, unsigned int index)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
-    char        *dl_path = NULL;
+    unsigned    num_paths;              /* Current number of stored paths */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "*sIu", plugin_path, index);
-    if(NULL == plugin_path)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "no path provided")
-    if(index >= H5PL_MAX_PATH_NUM)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "index path out of bounds for table")
-    if(NULL == (dl_path = H5MM_strdup(plugin_path)))
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
+    H5TRACE2("e", "*sIu", search_path, index);
 
-    H5PL_EXPAND_ENV_VAR
+    /* Check args */
+    if (NULL == search_path)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_path parameter cannot be NULL")
+    if (0 == HDstrlen(search_path))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_path parameter cannot have length zero")
 
-    if(H5PL_path_table_g[index])
-        H5PL_path_table_g[index] = (char *)H5MM_xfree(H5PL_path_table_g[index]);
-    H5PL_path_table_g[index] = dl_path;
+    /* Check index */
+    num_paths = H5PL__get_num_paths();
+    if (0 == num_paths)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "path table is empty")
+    else if (index >= num_paths)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index path out of bounds for table - can't be more than %u", (num_paths - 1))
+
+    /* Insert the search path into the path table */
+    if (H5PL__replace_path(search_path, index) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINSERT, FAIL, "unable to replace search path")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5PLreplace() */
 
-
+
 /*-------------------------------------------------------------------------
- * Function: H5PLinsert
+ * Function:    H5PLinsert
  *
- * Purpose: Insert a plugin path at the specified index, moving other paths after the index.
+ * Purpose:     Insert a plugin search path at the specified index, moving
+ *              other paths after the index.
  *
- * Return: Non-negative or success.
+ * Return:      Success:    Non-negative
+ *              Failture:   Negative
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PLinsert(const char *plugin_path, unsigned int index)
+H5PLinsert(const char *search_path, unsigned int index)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
-    char        *dl_path = NULL;
-    unsigned int plindex;
+    unsigned    num_paths;              /* Current number of stored paths */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "*sIu", plugin_path, index);
-    if(H5PL_num_paths_g == H5PL_MAX_PATH_NUM)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "too many directories in path for table")
-    if(NULL == plugin_path)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "no path provided")
-    if(index >= H5PL_MAX_PATH_NUM)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "index path out of bounds for table")
-    if(NULL == (dl_path = H5MM_strdup(plugin_path)))
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
-
-    H5PL_EXPAND_ENV_VAR
-
-    for(plindex = (unsigned int)H5PL_num_paths_g; plindex > index; plindex--)
-        H5PL_path_table_g[plindex] = H5PL_path_table_g[plindex - 1];
-    H5PL_path_table_g[index] = dl_path;
-    H5PL_num_paths_g++;
+    H5TRACE2("e", "*sIu", search_path, index);
+
+    /* Check args */
+    if (NULL == search_path)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_path parameter cannot be NULL")
+    if (0 == HDstrlen(search_path))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "plugin_path parameter cannot have length zero")
+
+    /* Check index */
+    num_paths = H5PL__get_num_paths();
+    if ((0 != num_paths) && (index >= num_paths))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index path out of bounds for table - can't be more than %u", (num_paths - 1))
+
+    /* Insert the search path into the path table */
+    if (H5PL__insert_path(search_path, index) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINSERT, FAIL, "unable to insert search path")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5PLinsert() */
 
-
+
 /*-------------------------------------------------------------------------
- * Function: H5PLremove
+ * Function:    H5PLremove
+ *
+ * Purpose:     Remove the plugin path at the specifed index and compact
+ *              the list.
  *
- * Purpose: Remove the plugin path at the specifed index and compacting the list.
+ * Return:      Success:    Non-negative
+ *              Failture:   Negative
  *
- * Return: Non-negative or success.
+ * Return:      Non-negative or success.
  *
  *-------------------------------------------------------------------------
  */
 herr_t
 H5PLremove(unsigned int index)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
-    unsigned int plindex;
+    unsigned    num_paths;              /* Current number of stored paths */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE1("e", "Iu", index);
-    if(H5PL_num_paths_g == 0)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "no directories in table")
-    if(index >= H5PL_MAX_PATH_NUM)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "index path out of bounds for table")
-    if(NULL == H5PL_path_table_g[index])
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "no directory path at index")
-    H5PL_path_table_g[index] = (char *)H5MM_xfree(H5PL_path_table_g[index]);
-
-    H5PL_num_paths_g--;
-    for(plindex = index; plindex < (unsigned int)H5PL_num_paths_g; plindex++)
-        H5PL_path_table_g[plindex] = H5PL_path_table_g[plindex + 1];
-    H5PL_path_table_g[H5PL_num_paths_g] = NULL;
+
+    /* Check index */
+    num_paths = H5PL__get_num_paths();
+    if (0 == num_paths)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "path table is empty")
+    else if (index >= num_paths)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index path out of bounds for table - can't be more than %u", (num_paths - 1))
+
+    /* Delete the search path from the path table */
+    if (H5PL__remove_path(index) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTDELETE, FAIL, "unable to remove search path")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5PLremove() */
 
-
+
 /*-------------------------------------------------------------------------
- * Function: H5PLget
+ * Function:    H5PLget
+ *
+ * Purpose:     Query the plugin path at a specified index.
+ *
+ *  If 'path_buf' is non-NULL then up to 'buf_size' bytes will be written into
+ *  that buffer and the length of the path name will be returned.
  *
- * Purpose: Query the plugin path at the specified index.
+ *  If 'path_buf' is NULL, this function will simply return the number of
+ *  characters required to store the path name, ignoring 'path_buf' and
+ *  'buf_size'
  *
- * Return: Success: The length of path.
+ *  If an error occurs then the buffer pointed to by 'path_buf'
+ *  (NULL or non-NULL) will be unchanged and the function will return a
+ *  negative value.
  *
- *  If `pathname' is non-NULL then write up to `size' bytes into that
- *  buffer and always return the length of the pathname.
- *  Otherwise `size' is ignored and the function does not store the pathname,
- *  just returning the number of characters required to store the pathname.
- *  If an error occurs then the buffer pointed to by `pathname' (NULL or non-NULL)
- *  is unchanged and the function returns a negative value.
- *  If a zero is returned for the name's length, then there is no pathname
- *  associated with the index.
+ *  If a zero is returned for the name's length, then there is no path name
+ *  associated with the index and the 'path_buf' buffer will be unchanged.
+ *
+ * Return:  Success:    The length of path
+ *          Failure:    A negative value
  *
  *-------------------------------------------------------------------------
  */
 ssize_t
-H5PLget(unsigned int index, char *pathname/*out*/, size_t size)
+H5PLget(unsigned int index, char *path_buf, size_t buf_size)
 {
-    ssize_t      ret_value = 0;    /* Return value */
-    size_t       len = 0;          /* Length of pathname */
-    char        *dl_path = NULL;
+    unsigned    num_paths;              /* Current number of stored paths */
+    const char *path = NULL;            /* path from table */
+    size_t      path_len = 0;           /* Length of path */
+    ssize_t     ret_value = 0;          /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE3("Zs", "Iuxz", index, pathname, size);
-    if(H5PL_num_paths_g == 0)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "no directories in table")
-    if(index >= H5PL_MAX_PATH_NUM)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "index path out of bounds for table")
-    if(NULL == (dl_path = H5PL_path_table_g[index]))
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "no directory path at index")
-    len = HDstrlen(dl_path);
-    if(pathname) {
-        HDstrncpy(pathname, dl_path, MIN((size_t)(len + 1), size));
-        if((size_t)len >= size)
-            pathname[size - 1] = '\0';
+    H5TRACE3("Zs", "Iu*sz", index, path_buf, buf_size);
+
+    /* Check index */
+    num_paths = H5PL__get_num_paths();
+    if (0 == num_paths)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "path table is empty")
+    else if (index >= num_paths)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "index path out of bounds for table - can't be more than %u", (num_paths - 1))
+
+    /* Check if the search table is empty */
+    if (H5PL__get_num_paths() == 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, (-1), "plugin search path table is empty")
+
+    /* Get the path at the specified index and its length */
+    if (NULL == (path = H5PL__get_path(index)))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_BADVALUE, (-1), "no path stored at that index")
+    path_len = HDstrlen(path);
+
+    /* If the path buffer is not NULL, copy the path to the buffer */
+    if (path_buf) {
+        HDstrncpy(path_buf, path, MIN((size_t)(path_len + 1), buf_size));
+        if ((size_t)path_len >= buf_size)
+            path_buf[buf_size - 1] = '\0';
     } /* end if */
 
     /* Set return value */
-    ret_value = (ssize_t)len;
+    ret_value = (ssize_t)path_len;
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5PLget() */
 
-
+
 /*-------------------------------------------------------------------------
- * Function: H5PLsize
+ * Function:    H5PLsize
  *
- * Purpose: Query the size of the current list of plugin paths.
+ * Purpose:     Get the number of stored plugin paths.
+ *              XXX: This is a terrible name. Can it be changed?
  *
- * Return: Plugin path size
+ * Return:      SUCCEED/FAIL
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5PLsize(unsigned int *listsize)
+H5PLsize(unsigned int *num_paths)
 {
     herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE1("e", "*Iu", listsize);
+    H5TRACE1("e", "*Iu", num_paths);
 
-    *listsize = (unsigned int)H5PL_num_paths_g;
+    /* Check arguments */
+    if (!num_paths)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "num_paths parameter cannot be NULL")
+
+    /* Get the number of stored plugin paths */
+    *num_paths = H5PL__get_num_paths();
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5PLsize() */
 
-
-/*-------------------------------------------------------------------------
- * Function:    H5PL__init_path_table
- *
- * Purpose:     Initialize the path table.
- *
- * Return:      Non-negative on success/Negative on failure
- *
- * Programmer:  Quincey Koziol
- *              18 March 2013
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5PL__init_path_table(void)
-{
-    char        *dl_path = NULL;
-    char        *origin_dl_path;
-    char        *dir;
-    herr_t      ret_value = SUCCEED;    /* Return value */
-
-    FUNC_ENTER_STATIC
-
-    /* Retrieve paths from HDF5_PLUGIN_PATH if the user sets it
-     * or from the default paths if it isn't set.
-     */
-    origin_dl_path = HDgetenv("HDF5_PLUGIN_PATH");
-    if(NULL == origin_dl_path)
-        dl_path = H5MM_strdup(H5PL_DEFAULT_PATH);
-    else
-        dl_path = H5MM_strdup(origin_dl_path);
-    if(NULL == dl_path)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
-
-    H5PL_EXPAND_ENV_VAR
-
-    /* Put paths in the path table.  They are separated by ":" */
-    dir = HDstrtok(dl_path, H5PL_PATH_SEPARATOR);
-    while(dir) {
-        /* Check for too many directories in path */
-        if(H5PL_num_paths_g == H5PL_MAX_PATH_NUM)
-            HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "too many directories in path for table")
-        if(NULL == (H5PL_path_table_g[H5PL_num_paths_g] = H5MM_strdup(dir)))
-            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
-        H5PL_num_paths_g++;
-        dir = HDstrtok(NULL, H5PL_PATH_SEPARATOR);
-    } /* end while */
-
-    H5PL_path_found_g = TRUE;
-
-done:
-    if(dl_path)
-        dl_path = (char *)H5MM_xfree(dl_path);
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5PL__init_path_table() */
-
-
-/*-------------------------------------------------------------------------
- * Function:    H5PL__find
- *
- * Purpose:     Given a path, this function opens the directory and envokes
- *              another function to go through all files to find the right
- *              plugin library. Two function definitions are for Unix and
- *              Windows.
- *
- * Return:      TRUE on success,
- *              FALSE on not found,
- *              negative on failure
- *
- * Programmer:  Raymond Lu
- *              13 February 2013
- *
- *-------------------------------------------------------------------------
- */
-#ifndef H5_HAVE_WIN32_API
-static htri_t
-H5PL__find(H5PL_type_t plugin_type, int type_id, char *dir, const void **info)
-{
-    char           *pathname = NULL;
-    DIR            *dirp = NULL;
-    struct dirent  *dp;
-    htri_t         ret_value = FALSE;
-
-    FUNC_ENTER_STATIC
-
-    /* Open the directory */
-    if(!(dirp = HDopendir(dir)))
-        HGOTO_ERROR(H5E_PLUGIN, H5E_OPENERROR, FAIL, "can't open directory: %s", dir)
-
-    /* Iterates through all entries in the directory to find the right plugin library */
-    while(NULL != (dp = HDreaddir(dirp))) {
-        /* The library we are looking for should be called libxxx.so... on Unix
-         * or libxxx.xxx.dylib on Mac.
-         */
-#ifndef __CYGWIN__
-        if(!HDstrncmp(dp->d_name, "lib", (size_t)3) &&
-                (HDstrstr(dp->d_name, ".so") || HDstrstr(dp->d_name, ".dylib"))) {
-#else
-        if(!HDstrncmp(dp->d_name, "cyg", (size_t)3) &&
-                HDstrstr(dp->d_name, ".dll") ) {
-
-#endif
-            h5_stat_t   my_stat;
-            size_t      pathname_len;
-            htri_t      found_in_dir;
-
-            /* Allocate & initialize the path name */
-            pathname_len = HDstrlen(dir) + HDstrlen(dp->d_name) + 2;
-            if(NULL == (pathname = (char *)H5MM_malloc(pathname_len)))
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
-            HDsnprintf(pathname, pathname_len, "%s/%s", dir, dp->d_name);
-
-            /* Get info for directory entry */
-            if(HDstat(pathname, &my_stat) == -1)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't stat file: %s", HDstrerror(errno))
-
-            /* If it is a directory, skip it */
-            if(S_ISDIR(my_stat.st_mode))
-                continue;
-
-            /* Attempt to open the dynamic library as a filter library */
-            if((found_in_dir = H5PL__open(plugin_type, pathname, type_id, info)) < 0)
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "search in directory failed")
-            if(found_in_dir)
-                HGOTO_DONE(TRUE)    /* Indicate success */
-            pathname = (char *)H5MM_xfree(pathname);
-        } /* end if */
-    } /* end while */
-
-done:
-    if(dirp)
-        if(HDclosedir(dirp) < 0)
-            HDONE_ERROR(H5E_FILE, H5E_CLOSEERROR, FAIL, "can't close directory: %s", HDstrerror(errno))
-    pathname = (char *)H5MM_xfree(pathname);
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5PL__find() */
-#else /* H5_HAVE_WIN32_API */
-static htri_t
-H5PL__find(H5PL_type_t plugin_type, int type_id, char *dir, const void **info)
-{
-    WIN32_FIND_DATAA    fdFile;
-    HANDLE              hFind;
-    char                *pathname = NULL;
-    char                service[2048];
-    htri_t              ret_value = FALSE;
-
-    FUNC_ENTER_STATIC
-
-    /* Specify a file mask. *.* = We want everything! */
-    sprintf(service, "%s\\*.dll", dir);
-    if((hFind = FindFirstFileA(service, &fdFile)) == INVALID_HANDLE_VALUE)
-        HGOTO_ERROR(H5E_PLUGIN, H5E_OPENERROR, FAIL, "can't open directory")
-
-    do {
-        /* Find first file will always return "."
-         * and ".." as the first two directories.
-         */
-        if(HDstrcmp(fdFile.cFileName, ".") != 0 && HDstrcmp(fdFile.cFileName, "..") != 0) {
-            size_t      pathname_len;
-            htri_t      found_in_dir;
-
-            /* Allocate & initialize the path name */
-            pathname_len = HDstrlen(dir) + HDstrlen(fdFile.cFileName) + 2;
-            if(NULL == (pathname = (char *)H5MM_malloc(pathname_len)))
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
-            HDsnprintf(pathname, pathname_len, "%s\\%s", dir, fdFile.cFileName);
-
-            /* Is the entity a File or Folder? */
-            if(fdFile.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
-                continue;
-
-            if((found_in_dir = H5PL__open(plugin_type, pathname, type_id, info)) < 0)
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "search in directory failed")
-            if(found_in_dir)
-                HGOTO_DONE(TRUE)    /* Indicate success */
-            pathname = (char *)H5MM_xfree(pathname);
-        } /* end if */
-    } while(FindNextFileA(hFind, &fdFile)); /* Find the next file. */
-
-done:
-    if(hFind)
-        FindClose(hFind);
-    if(pathname)
-        pathname = (char *)H5MM_xfree(pathname);
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5PL__find() */
-#endif /* H5_HAVE_WIN32_API */
-
-
-/*-------------------------------------------------------------------------
- * Function:    H5PL__open
- *
- * Purpose:     Iterates through all files to find the right plugin library.
- *              It loads the dynamic plugin library and keeps it on the list
- *              of loaded libraries.
- *
- * Return:      TRUE on success,
- *              FALSE on not found,
- *              negative on failure
- *
- * Programmer:  Raymond Lu
- *              13 February 2013
- *
- *-------------------------------------------------------------------------
- */
-static htri_t
-H5PL__open(H5PL_type_t pl_type, char *libname, int pl_id, const void **pl_info)
-{
-    H5PL_HANDLE    handle = NULL;
-    htri_t         ret_value = FALSE;
-
-    FUNC_ENTER_STATIC
-
-    /* There are different reasons why a library can't be open, e.g. wrong architecture.
-     * simply continue if we can't open it.
-     */
-    if(NULL == (handle = H5PL_OPEN_DLIB(libname))) {
-        H5PL_CLR_ERROR; /* clear error */
-    } /* end if */
-    else {
-        H5PL_get_plugin_info_t get_plugin_info = NULL;
-
-        /* Return a handle for the function H5PLget_plugin_info in the dynamic library.
-         * The plugin library is suppose to define this function.
-         */
-        if(NULL == (get_plugin_info = (H5PL_get_plugin_info_t)H5PL_GET_LIB_FUNC(handle, "H5PLget_plugin_info"))) {
-            if(H5PL__close(handle) < 0)
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
-        } /* end if */
-        else {
-            const H5Z_class2_t *plugin_info;
-
-            /* Invoke H5PLget_plugin_info to verify this is the right library we are looking for.
-             * Move on if it isn't.
-             */
-            if(NULL == (plugin_info = (const H5Z_class2_t *)(*get_plugin_info)())) {
-                if(H5PL__close(handle) < 0)
-                    HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "can't get plugin info")
-            } /* end if */
-
-            /* Successfully found plugin library, check if it's the right one */
-            if(plugin_info->id == pl_id) {
-                /* Expand the table if it is too small */
-                if(H5PL_table_used_g >= H5PL_table_alloc_g) {
-                    size_t n = MAX(H5Z_MAX_NFILTERS, 2 * H5PL_table_alloc_g);
-                    H5PL_table_t *table = (H5PL_table_t *)H5MM_realloc(H5PL_table_g, n * sizeof(H5PL_table_t));
-
-                    if(!table)
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to extend dynamic library table")
-
-                    H5PL_table_g = table;
-                    H5PL_table_alloc_g = n;
-                } /* end if */
-
-                (H5PL_table_g[H5PL_table_used_g]).handle = handle;
-                (H5PL_table_g[H5PL_table_used_g]).pl_type = pl_type;
-                (H5PL_table_g[H5PL_table_used_g]).pl_id = plugin_info->id;
-                H5PL_table_used_g++;
-
-                /* Set the plugin info to return */
-                *pl_info = (const void *)plugin_info;
-
-                /* Indicate success */
-                ret_value = TRUE;
-            } /* end if */
-            else
-                if(H5PL__close(handle) < 0)
-                    HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
-        } /* end if */
-    } /* end else */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5PL__open() */
-
-
-/*-------------------------------------------------------------------------
- * Function:    H5PL__search_table
- *
- * Purpose:     Search in the list of already opened dynamic libraries
- *              to see if the one we are looking for is already opened.
- *
- * Return:      TRUE on success,
- *              FALSE on not found,
- *              Negative on failure
- *
- * Programmer:  Raymond Lu
- *              13 February 2013
- *
- *-------------------------------------------------------------------------
- */
-static htri_t
-H5PL__search_table(H5PL_type_t plugin_type, int type_id, const void **info)
-{
-    htri_t         ret_value = FALSE;
-
-    FUNC_ENTER_STATIC
-
-    /* Search in the table of already opened dynamic libraries */
-    if(H5PL_table_used_g > 0) {
-        size_t         i;
-
-        for(i = 0; i < H5PL_table_used_g; i++) {
-            if((plugin_type == (H5PL_table_g[i]).pl_type) && (type_id == (H5PL_table_g[i]).pl_id)) {
-                H5PL_get_plugin_info_t get_plugin_info;
-                const H5Z_class2_t   *plugin_info;
-
-                if(NULL == (get_plugin_info = (H5PL_get_plugin_info_t)H5PL_GET_LIB_FUNC((H5PL_table_g[i]).handle, "H5PLget_plugin_info")))
-                    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "can't get function for H5PLget_plugin_info")
-
-                if(NULL == (plugin_info = (const H5Z_class2_t *)(*get_plugin_info)()))
-                    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "can't get plugin info")
-
-                *info = plugin_info;
-                HGOTO_DONE(TRUE)
-            } /* end if */
-        } /* end for */
-    } /* end if */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5PL__search_table() */
-
-
-/*-------------------------------------------------------------------------
- * Function:    H5PL__close
- *
- * Purpose:     Closes the handle for dynamic library
- *
- * Return:      Non-negative on success/Negative on failure
- *
- * Programmer:  Raymond Lu
- *              13 February 2013
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5PL__close(H5PL_HANDLE handle)
-{
-    FUNC_ENTER_STATIC_NOERR
-
-    H5PL_CLOSE_LIB(handle);
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5PL__close() */
-
diff --git a/src/H5PLextern.h b/src/H5PLextern.h
index 7547ad7..cd5464d 100644
--- a/src/H5PLextern.h
+++ b/src/H5PLextern.h
@@ -11,9 +11,9 @@
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
 /*
- * Programmer:  Raymond Lu <songyulu@hdfgroup.org>
- *              13 February 2013
+ * Purpose:     Header file for writing external HDF5 plugins.
  */
+
 #ifndef _H5PLextern_H
 #define _H5PLextern_H
 
diff --git a/src/H5PLint.c b/src/H5PLint.c
new file mode 100644
index 0000000..bd6bf7d
--- /dev/null
+++ b/src/H5PLint.c
@@ -0,0 +1,381 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5. The full HDF5 copyright notice, including      *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Purpose: Internal routines for managing plugins.
+ *
+ */
+
+
+/****************/
+/* Module Setup */
+/****************/
+
+#include "H5PLmodule.h"          /* This source code file is part of the H5PL module */
+
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"      /* Generic Functions            */
+#include "H5Eprivate.h"     /* Error handling               */
+#include "H5MMprivate.h"    /* Memory management            */
+#include "H5PLpkg.h"        /* Plugin                       */
+#include "H5Zprivate.h"     /* Filter pipeline              */
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+/* Package initialization variable */
+hbool_t H5_PKG_INIT_VAR = FALSE;
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+/* Bitmask that controls whether classes of plugins
+ * (e.g.: filters, VOL drivers) can be loaded.
+ */
+static unsigned int     H5PL_plugin_control_mask_g = H5PL_ALL_PLUGIN;
+
+/* This flag will be set to FALSE if the HDF5_PLUGIN_PRELOAD
+ * environment variable was set to H5PL_NO_PLUGIN at
+ * package initialization.
+ */
+static hbool_t          H5PL_allow_plugins_g = TRUE;
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__get_plugin_control_mask
+ *
+ * Purpose:     Gets the internal plugin control mask value.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__get_plugin_control_mask(unsigned int *mask /*out*/)
+{
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE_NOERR
+
+    /* Check args - Just assert on package functions */
+    HDassert(mask);
+
+    /* Return the mask */
+    *mask = H5PL_plugin_control_mask_g;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+
+} /* end H5PL__get_plugin_control_mask() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__set_plugin_control_mask
+ *
+ * Purpose:     Sets the internal plugin control mask value.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__set_plugin_control_mask(unsigned int mask)
+{
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE_NOERR
+
+    /* Only allow setting this if plugins have not been disabled.
+     * XXX: Note that we don't consider this an error, but instead
+     *      silently ignore it. We may want to consider this behavior
+     *      more carefully.
+     */
+    if (H5PL_allow_plugins_g)
+        H5PL_plugin_control_mask_g = mask;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+
+} /* end H5PL__set_plugin_control_mask() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__init_package
+ *
+ * Purpose:     Initialize any package-specific data and call any init
+ *              routines for the package.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__init_package(void)
+{
+    char        *env_var = NULL;
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check the environment variable to determine if the user wants
+     * to ignore plugins. The special symbol H5PL_NO_PLUGIN (defined in
+     * H5PLpublic.h) means we don't want to load plugins.
+     */
+    if (NULL != (env_var = HDgetenv("HDF5_PLUGIN_PRELOAD")))
+        if (!HDstrcmp(env_var, H5PL_NO_PLUGIN)) {
+            H5PL_plugin_control_mask_g = 0;
+            H5PL_allow_plugins_g = FALSE;
+        }
+
+    /* Create the table of previously-loaded plugins */
+    if (H5PL__create_plugin_cache() < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINIT, FAIL, "can't create plugin cache")
+
+    /* Create the table of search paths for dynamic libraries */
+    if (H5PL__create_path_table() < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINIT, FAIL, "can't create plugin search path table")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__init_package() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL_term_package
+ *
+ * Purpose:     Terminate the H5PL interface: release all memory, reset all
+ *              global variables to initial values. This only happens if all
+ *              types have been destroyed from other interfaces.
+ *
+ * Return:      Success:    Positive if any action was taken that might
+ *                          affect some other interface; zero otherwise
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+H5PL_term_package(void)
+{
+    hbool_t already_closed = FALSE;
+    int     ret_value = 0;
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    if (H5_PKG_INIT_VAR) {
+
+        /* Close the plugin cache.
+         * We need to bump the return value if we did any real work here.
+         */
+        if (H5PL__close_plugin_cache(&already_closed) < 0)
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTFREE, (-1), "problem closing plugin cache")
+        if (!already_closed)
+            ret_value++;
+
+        /* Close the search path table and free the paths */
+        if (H5PL__close_path_table() < 0)
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTFREE, (-1), "problem closing search path table")
+
+        /* Mark the interface as uninitialized */
+        if (0 == ret_value)
+            H5_PKG_INIT_VAR = FALSE;
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL_term_package() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL_load
+ *
+ * Purpose:     Given the plugin type and identifier, this function searches
+ *              for and, if found, loads a dynamic plugin library.
+ *
+ *              The function searches first in the cached plugins and then
+ *              in the paths listed in the path table.
+ *
+ * Return:      Success:    A pointer to the plugin info
+ *              Failure:    NULL
+ *
+ *-------------------------------------------------------------------------
+ */
+const void *
+H5PL_load(H5PL_type_t type, int id)
+{
+    H5PL_search_params_t    search_params;
+    hbool_t                 found = FALSE;          /* Whether the plugin was found */
+    const void             *plugin_info = NULL;
+    const void             *ret_value = NULL;
+
+    FUNC_ENTER_NOAPI(NULL)
+
+    /* Check if plugins can be loaded for this plugin type */
+    switch (type) {
+        case H5PL_TYPE_FILTER:
+            if ((H5PL_plugin_control_mask_g & H5PL_FILTER_PLUGIN) == 0)
+                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTLOAD, NULL, "required dynamically loaded plugin filter '%d' is not available", id)
+            break;
+
+        case H5PL_TYPE_ERROR:
+        case H5PL_TYPE_NONE:
+        default:
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTLOAD, NULL, "required dynamically loaded plugin '%d' is not valid", id)
+    }
+
+    /* Set up the search parameters */
+    search_params.type = type;
+    search_params.id = id;
+
+    /* Search in the table of already loaded plugin libraries */
+    if(H5PL__find_plugin_in_cache(&search_params, &found, &plugin_info) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, NULL, "search in plugin cache  failed")
+
+    /* If not found, try iterating through the path table to find an appropriate plugin */
+    if (!found)
+        if (H5PL__find_plugin_in_path_table(&search_params, &found, &plugin_info) < 0)
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, NULL, "search in path table failed")
+
+    /* Set the return value we found the plugin */
+    if (found)
+        ret_value = plugin_info;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL_load() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__open
+ *
+ * Purpose:     Opens a plugin.
+ *
+ *              The success parameter will be set to TRUE and the plugin_info
+ *              parameter will be filled in on success. Otherwise, they
+ *              will be FALSE and NULL, respectively.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__open(const char *path, H5PL_type_t type, int id, hbool_t *success, const void **plugin_info)
+{
+    H5PL_HANDLE             handle = NULL;
+    H5PL_get_plugin_info_t  get_plugin_info = NULL;
+    htri_t                  ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args - Just assert on package functions */
+    HDassert(path);
+    HDassert(success);
+    HDassert(plugin_info);
+
+    /* Initialize out parameters */
+    *success = FALSE;
+    *plugin_info = NULL;
+
+    /* There are different reasons why a library can't be open, e.g. wrong architecture.
+     * If we can't open the library, just return.
+     */
+    if (NULL == (handle = H5PL_OPEN_DLIB(path))) {
+        H5PL_CLR_ERROR; /* clear error */
+        HGOTO_DONE(SUCCEED);
+    }
+
+
+    /* Return a handle for the function H5PLget_plugin_info in the dynamic library.
+     * The plugin library is suppose to define this function.
+     *
+     * NOTE: We turn off -Wpedantic in gcc to quiet a warning about converting
+     *       object pointers to function pointers, which is undefined in ANSI C.
+     *       This is basically unavoidable due to the nature of dlsym() and *is*
+     *       defined in POSIX, so it's fine.
+     */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+    if (NULL != (get_plugin_info = (H5PL_get_plugin_info_t)H5PL_GET_LIB_FUNC(handle, "H5PLget_plugin_info"))) {
+#pragma GCC diagnostic pop
+
+        const H5Z_class2_t *info;
+
+        /* Get the plugin info */
+        if (NULL == (info = (const H5Z_class2_t *)(*get_plugin_info)()))
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "can't get plugin info")
+
+        /* Check if the filter IDs match */
+        if (info->id == id) {
+
+            /* Store the plugin in the cache */
+            if (H5PL__add_plugin(type, id, handle))
+                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINSERT, FAIL, "unable to add new plugin to plugin cache")
+
+            /* Set output parameters */
+            *success = TRUE;
+            *plugin_info = (const void *)info;
+        }
+    }
+
+done:
+    if (!success && handle)
+        if (H5PL__close(handle) < 0)
+            HDONE_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__open() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__close
+ *
+ * Purpose:     Closes the handle for dynamic library
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__close(H5PL_HANDLE handle)
+{
+    FUNC_ENTER_PACKAGE_NOERR
+
+    H5PL_CLOSE_LIB(handle);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5PL__close() */
+
diff --git a/src/H5PLmodule.h b/src/H5PLmodule.h
index b441aed..945441e 100644
--- a/src/H5PLmodule.h
+++ b/src/H5PLmodule.h
@@ -11,13 +11,11 @@
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
 /*
- * Programmer:	Quincey Koziol <koziol@hdfgroup.org>
- *		Saturday, September 12, 2015
- *
- * Purpose:	This file contains declarations which define macros for the
- *		H5PL package.  Including this header means that the source file
- *		is part of the H5PL package.
+ * Purpose: This file contains declarations which define macros for the
+ *          H5PL package.  Including this header means that the source file
+ *          is part of the H5PL package.
  */
+
 #ifndef _H5PLmodule_H
 #define _H5PLmodule_H
 
diff --git a/src/H5PLpath.c b/src/H5PLpath.c
new file mode 100644
index 0000000..435802a
--- /dev/null
+++ b/src/H5PLpath.c
@@ -0,0 +1,776 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5. The full HDF5 copyright notice, including      *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Purpose: Code to implement a path table which stores plugin search paths.
+ *
+ *          The path table is implemented as a dynamic, global array which
+ *          will grow as new paths are inserted. The capacity of the path
+ *          table never shrinks (though given the low number of paths
+ *          expected and the low likelihood of paths being removed, this
+ *          seems unlikely to be a problem). Inserts and removals rework
+ *          the array so that there are no 'holes' in the in-use part
+ *          of the array.
+ *
+ *          Note that it's basically up to the user to manage the indexes
+ *          when a complicated series of insert, overwrite, and, remove
+ *          operations take place.
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#include "H5PLmodule.h"          /* This source code file is part of the H5PL module */
+
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"      /* Generic Functions            */
+#include "H5Eprivate.h"     /* Error handling               */
+#include "H5MMprivate.h"    /* Memory management            */
+#include "H5PLpkg.h"        /* Plugin                       */
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+/* Initial capacity of the path table */
+#define H5PL_INITIAL_PATH_CAPACITY      16
+
+/* The amount to add to the capacity when the table is full */
+#define H5PL_PATH_CAPACITY_ADD          16
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+static herr_t H5PL__insert_at(const char *path, unsigned int index);
+static herr_t H5PL__make_space_at(unsigned int index);
+static herr_t H5PL__replace_at(const char *path, unsigned int index);
+static herr_t H5PL__expand_path_table(void);
+static herr_t H5PL__find_plugin_in_path(const H5PL_search_params_t *search_params, hbool_t *found, const char *dir, const void **plugin_info);
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+/* Stored plugin paths to search */
+static char       **H5PL_paths_g = NULL;
+
+/* The number of stored paths */
+static unsigned     H5PL_num_paths_g = 0;
+
+/* The capacity of the path table */
+static unsigned     H5PL_path_capacity_g = H5PL_INITIAL_PATH_CAPACITY;
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__insert_at()
+ *
+ * Purpose:     Insert a path at a particular index in the path table.
+ *              Does not clobber! Will move existing paths up to make
+ *              room. Use H5PL__replace_at(index) if you want to clobber.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5PL__insert_at(const char *path, unsigned int index)
+{
+    char    *path_copy = NULL;      /* copy of path string (for storing) */
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Check args - Just assert on package functions */
+    HDassert(path);
+    HDassert(HDstrlen(path));
+
+    /* Expand the table if it is full */
+    if (H5PL_num_paths_g == H5PL_path_capacity_g)
+        if (H5PL__expand_path_table() < 0)
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't expand path table")
+
+    /* Copy the path for storage so the caller can dispose of theirs */
+    if (NULL == (path_copy = H5MM_strdup(path)))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't make internal copy of path")
+
+#ifdef H5_HAVE_WIN32_API
+    /* Clean up Microsoft Windows environment variables in the path string */
+    if(H5_expand_windows_env_vars(&path_copy))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTCONVERT, FAIL, "can't expand environment variable string")
+#endif /* H5_HAVE_WIN32_API */
+
+    /* If the table entry is in use, make some space */
+    if (H5PL_paths_g[index])
+        if (H5PL__make_space_at(index) < 0)
+            HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "unable to make space in the table for the new entry")
+
+    /* Insert the copy of the search path into the table at the specified index */
+    H5PL_paths_g[index] = path_copy;
+    H5PL_num_paths_g++;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__insert_at() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__make_space_at()
+ *
+ * Purpose:     Free up a slot in the path table, moving existing path
+ *              entries as necessary.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5PL__make_space_at(unsigned int index)
+{
+    unsigned    u;                      /* iterator */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check args - Just assert on package functions */
+    HDassert(index < H5PL_path_capacity_g);
+
+    /* Copy the paths back to make a space  */
+    for (u = H5PL_num_paths_g; u > index; u--)
+        H5PL_paths_g[u] = H5PL_paths_g[u-1];
+
+    H5PL_paths_g[index] = NULL;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__make_space_at() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__replace_at()
+ *
+ * Purpose:     Replace a path at a particular index in the path table.
+ *              The path in the table must exist and will be freed by this
+ *              function.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5PL__replace_at(const char *path, unsigned int index)
+{
+    char    *path_copy = NULL;      /* copy of path string (for storing) */
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Check args - Just assert on package functions */
+    HDassert(path);
+    HDassert(HDstrlen(path));
+
+    /* Check that the table entry is in use */
+    if (!H5PL_paths_g[index])
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTFREE, FAIL, "path entry at index %u in the table is NULL", index)
+
+    /* Copy the path for storage so the caller can dispose of theirs */
+    if (NULL == (path_copy = H5MM_strdup(path)))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't make internal copy of path")
+
+#ifdef H5_HAVE_WIN32_API
+        /* Clean up Microsoft Windows environment variables in the path string */
+        if (H5_expand_windows_env_vars(&path_copy))
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTCONVERT, FAIL, "can't expand environment variable string")
+#endif /* H5_HAVE_WIN32_API */
+
+    /* Free the existing path entry */
+    H5PL_paths_g[index] = (char *)H5MM_xfree(H5PL_paths_g[index]);
+
+    /* Copy the search path into the table at the specified index */
+    H5PL_paths_g[index] = path_copy;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__replace_at() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__create_path_table
+ *
+ * Purpose:     Create the collection of paths that will be searched
+ *              when loading plugins.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__create_path_table(void)
+{
+    char        *env_var= NULL;         /* Path string from environment variable */
+    char        *paths = NULL;          /* Delimited paths string. Either from the
+                                         * environment variable or the default.
+                                         */
+    char        *next_path = NULL;      /* A path tokenized from the paths string */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Allocate memory for the path table */
+    H5PL_num_paths_g = 0;
+    H5PL_path_capacity_g = H5PL_INITIAL_PATH_CAPACITY;
+    if (NULL == (H5PL_paths_g = (char **)H5MM_calloc((size_t)H5PL_path_capacity_g * sizeof(char *))))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path table")
+
+    /* Retrieve paths from HDF5_PLUGIN_PATH if the user sets it
+     * or from the default paths if it isn't set.
+     */
+    env_var = HDgetenv("HDF5_PLUGIN_PATH");
+    if (NULL == env_var)
+        paths = H5MM_strdup(H5PL_DEFAULT_PATH);
+    else
+        paths = H5MM_strdup(env_var);
+
+    if (NULL == paths)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path copy")
+
+    /* Separate the paths and store them */
+    /* XXX: strtok() is not thread-safe */
+    next_path = HDstrtok(paths, H5PL_PATH_SEPARATOR);
+    while (next_path) {
+
+        /* Insert the path into the table */
+        if (H5PL__append_path(next_path) < 0)
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't insert path: %s", next_path)
+
+        /* Get the next path from the environment string */
+        next_path = HDstrtok(NULL, H5PL_PATH_SEPARATOR);
+    } /* end while */
+
+done:
+    if (paths)
+        paths = (char *)H5MM_xfree(paths);
+
+    /* Try to clean up on errors */
+    if (FAIL == ret_value) {
+        if (H5PL_paths_g)
+            H5PL_paths_g = (char **)H5MM_xfree(H5PL_paths_g);
+        H5PL_path_capacity_g = 0;
+    }
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__create_path_table() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__close_path_table
+ *
+ * Purpose:     Close the collection of paths that will be searched
+ *              when loading plugins.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__close_path_table(void)
+{
+    unsigned    u;                      /* iterator */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE_NOERR
+
+    /* Free paths */
+    for (u = 0; u < H5PL_num_paths_g; u++)
+        if (H5PL_paths_g[u])
+            H5PL_paths_g[u] = (char *)H5MM_xfree(H5PL_paths_g[u]);
+
+    /* Free path table */
+    H5PL_paths_g = (char **)H5MM_xfree(H5PL_paths_g);
+
+    /* Reset values */
+    H5PL_num_paths_g = 0;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+
+} /* end H5PL__close_path_table() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__get_num_paths
+ *
+ * Purpose:     Gets the number of plugin paths that have been stored.
+ *
+ * Return:      Success:    The number of paths
+ *              Failture:   Can't fail
+ *-------------------------------------------------------------------------
+ */
+unsigned
+H5PL__get_num_paths(void)
+{
+    FUNC_ENTER_PACKAGE_NOERR
+
+    FUNC_LEAVE_NOAPI(H5PL_num_paths_g)
+
+} /* end H5PL__get_num_paths() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__expand_path_table
+ *
+ * Purpose:     Expand the path table when it's full.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5PL__expand_path_table(void)
+{
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Update the capacity */
+    H5PL_path_capacity_g += H5PL_PATH_CAPACITY_ADD;
+
+    /* Resize the array */
+    if(NULL == (H5PL_paths_g = (char **)H5MM_realloc(H5PL_paths_g, (size_t)H5PL_path_capacity_g * sizeof(char *))))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "allocating additional memory for path table failed")
+
+    /* Initialize the new memory */
+    HDmemset(H5PL_paths_g + H5PL_num_paths_g, 0, (size_t)H5PL_PATH_CAPACITY_ADD * sizeof(char *));
+
+done:
+    /* Set the path capacity back if there were problems */
+    if (FAIL == ret_value)
+        H5PL_path_capacity_g -= H5PL_PATH_CAPACITY_ADD;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__expand_path_table() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__append_path
+ *
+ * Purpose:     Insert a path at the end of the table.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__append_path(const char *path)
+{
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args - Just assert on package functions */
+    HDassert(path);
+    HDassert(HDstrlen(path));
+
+    /* Insert the path at the end of the table */
+    if (H5PL__insert_at(path, H5PL_num_paths_g) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINSERT, FAIL, "unable to append search path")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__append_path() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__prepend_path
+ *
+ * Purpose:     Insert a path at the beginning of the table.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__prepend_path(const char *path)
+{
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args - Just assert on package functions */
+    HDassert(path);
+    HDassert(HDstrlen(path));
+
+    /* Insert the path at the beginning of the table */
+    if (H5PL__insert_at(path, 0) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINSERT, FAIL, "unable to prepend search path")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__prepend_path() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__replace_path
+ *
+ * Purpose:     Replace a path at particular index in the table.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__replace_path(const char *path, unsigned int index)
+{
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args - Just assert on package functions */
+    HDassert(path);
+    HDassert(HDstrlen(path));
+    HDassert(index < H5PL_path_capacity_g);
+
+    /* Insert the path at the requested index */
+    if (H5PL__replace_at(path, index) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINSERT, FAIL, "unable to replace search path")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__replace_path() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__insert_path
+ *
+ * Purpose:     Insert a path at particular index in the table, moving
+ *              any existing paths back to make space.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__insert_path(const char *path, unsigned int index)
+{
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args - Just assert on package functions */
+    HDassert(path);
+    HDassert(HDstrlen(path));
+    HDassert(index < H5PL_path_capacity_g);
+
+    /* Insert the path at the requested index */
+    if (H5PL__insert_at(path, index) < 0)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINSERT, FAIL, "unable to insert search path")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__insert_path() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__remove_path
+ *
+ * Purpose:     Remove a path at particular index in the table, freeing
+ *              the path string and moving the paths down to close the gap.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__remove_path(unsigned int index)
+{
+    unsigned    u;                      /* iterator */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args - Just assert on package functions */
+    HDassert(index < H5PL_path_capacity_g);
+
+    /* Check if the path at that index is set */
+    if (!H5PL_paths_g[index])
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTDELETE, FAIL, "search path at index %u is NULL", index)
+
+    /* Delete the path */
+    H5PL_num_paths_g--;
+    H5PL_paths_g[index] = (char *)H5MM_xfree(H5PL_paths_g[index]);
+
+    /* Shift the paths down to close the gap */
+    for (u = index; u < H5PL_num_paths_g; u++)
+        H5PL_paths_g[u] = H5PL_paths_g[u+1];
+
+    /* Set the (former) last path to NULL */
+    H5PL_paths_g[H5PL_num_paths_g] = NULL;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__remove_path() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__get_path
+ *
+ * Purpose:     Get a pointer to a path at particular index in the table.
+ *
+ * Return:      Success:    A pointer to a path string stored in the table
+ *              Failure:    NULL
+ *
+ *-------------------------------------------------------------------------
+ */
+const char *
+H5PL__get_path(unsigned int index)
+{
+    char    *ret_value = NULL;    /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Get the path at the requested index */
+    if (index >= H5PL_num_paths_g)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, NULL, "path index %u is out of range in table", index)
+
+    return H5PL_paths_g[index];
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__replace_path() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__find_plugin_in_path_table
+ *
+ * Purpose:     Attempts to find a matching plugin in the file system
+ *              using the paths stored in the path table.
+ *.
+ *              The 'found' parameter will be set appropriately.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__find_plugin_in_path_table(const H5PL_search_params_t *search_params, hbool_t *found, const void **plugin_info)
+{
+    unsigned int    u;                          /* iterator */
+    herr_t          ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args - Just assert on package functions */
+    HDassert(search_params);
+    HDassert(found);
+    HDassert(plugin_info);
+
+    /* Initialize output parameters */
+    *found = FALSE;
+    *plugin_info = NULL;
+
+    /* Loop over the paths in the table, checking for an appropriate plugin */
+    for (u = 0; u < H5PL_num_paths_g; u++) {
+
+        /* Search for the plugin in this path */
+        if (H5PL__find_plugin_in_path(search_params, found, H5PL_paths_g[u], plugin_info) < 0)
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "search in path %s encountered an error", H5PL_paths_g[u])
+
+        /* Break out if found */
+        if (*found) {
+            if (!plugin_info)
+                HGOTO_ERROR(H5E_PLUGIN, H5E_BADVALUE, FAIL, "plugin info should not be NULL")
+            break;
+        }
+    }
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__find_plugin_in_path_table() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__find_plugin_in_path
+ *
+ * Purpose:     Given a path, this function opens the directory and envokes
+ *              another function to go through all files to find the right
+ *              plugin library. Two function definitions are for Unix and
+ *              Windows.
+ *
+ *              The found parameter will be set to TRUE and the info
+ *              parameter will be filled in on success.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef H5_HAVE_WIN32_API
+static herr_t
+H5PL__find_plugin_in_path(const H5PL_search_params_t *search_params, hbool_t *found, const char *dir, const void **plugin_info)
+{
+    char           *path = NULL;
+    DIR            *dirp = NULL;            /* Directory stream */
+    struct dirent  *dp = NULL;              /* Directory entry */
+    herr_t         ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Check args - Just assert on package functions */
+    HDassert(search_params);
+    HDassert(found);
+    HDassert(dir);
+    HDassert(plugin_info);
+
+    /* Initialize the found parameter */
+    *found = FALSE;
+
+    /* Open the directory */
+    if (!(dirp = HDopendir(dir)))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_OPENERROR, FAIL, "can't open directory: %s", dir)
+
+    /* Iterate through all entries in the directory */
+    while (NULL != (dp = HDreaddir(dirp))) {
+
+        /* The library we are looking for should be called libxxx.so... on Unix
+         * or libxxx.xxx.dylib on Mac.
+         */
+#ifndef __CYGWIN__
+        if (!HDstrncmp(dp->d_name, "lib", (size_t)3) &&
+                (HDstrstr(dp->d_name, ".so") || HDstrstr(dp->d_name, ".dylib"))) {
+#else
+        if (!HDstrncmp(dp->d_name, "cyg", (size_t)3) &&
+                HDstrstr(dp->d_name, ".dll") ) {
+#endif
+
+            h5_stat_t   my_stat;
+            size_t      len;
+
+            /* Allocate & initialize the path name */
+            len = HDstrlen(dir) + HDstrlen(H5PL_PATH_SEPARATOR) + HDstrlen(dp->d_name) + 1 /*\0*/;
+
+            if (NULL == (path = (char *)H5MM_calloc(len)))
+                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
+
+            HDsnprintf(path, len, "%s/%s", dir, dp->d_name);
+
+            /* Get info for directory entry */
+            if (HDstat(path, &my_stat) == -1)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't stat file %s -- error was: %s", path, HDstrerror(errno))
+
+            /* If it is a directory, skip it */
+            if (S_ISDIR(my_stat.st_mode))
+                continue;
+
+            /* attempt to open the dynamic library as a filter library */
+            if (H5PL__open(path, search_params->type, search_params->id, found, plugin_info) < 0)
+                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "search in directory failed")
+            if (*found)
+                HGOTO_DONE(SUCCEED)
+
+            path = (char *)H5MM_xfree(path);
+        } /* end if */
+    } /* end while */
+
+done:
+    if (dirp)
+        if (HDclosedir(dirp) < 0)
+            HDONE_ERROR(H5E_FILE, H5E_CLOSEERROR, FAIL, "can't close directory: %s", HDstrerror(errno))
+
+    path = (char *)H5MM_xfree(path);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__find_plugin_in_path() */
+#else /* H5_HAVE_WIN32_API */
+static herr_t
+H5PL__find_plugin_in_path(const H5PL_search_params_t *search_params, hbool_t *found, const char *dir, const void **plugin_info)
+{
+    WIN32_FIND_DATAA    fdFile;
+    HANDLE              hFind = INVALID_HANDLE_VALUE;
+    char                *path = NULL;
+    char                service[2048];
+    herr_t              ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Check args - Just assert on package functions */
+    HDassert(search_params);
+    HDassert(found);
+    HDassert(dir);
+    HDassert(plugin_info);
+
+    /* Initialize the found parameter */
+    *found = FALSE;
+
+    /* Specify a file mask. *.* = We want everything! */
+    HDsprintf(service, "%s\\*.dll", dir);
+    if ((hFind = FindFirstFileA(service, &fdFile)) == INVALID_HANDLE_VALUE)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_OPENERROR, FAIL, "can't open directory")
+
+    /* Loop over all the files */
+    do {
+        /* Ignore '.' and '..' */
+        if (HDstrcmp(fdFile.cFileName, ".") != 0 && HDstrcmp(fdFile.cFileName, "..") != 0) {
+
+            /* XXX: Probably just continue here and move the code below over one tab */
+
+            size_t      len;
+
+            /* Allocate & initialize the path name */
+            len = HDstrlen(dir) + HDstrlen(H5PL_PATH_SEPARATOR) + HDstrlen(fdFile.cFileName) + 1;
+
+            if (NULL == (path = (char *)H5MM_calloc(len)))
+                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for path")
+
+            HDsnprintf(path, len, "%s\\%s", dir, fdFile.cFileName);
+
+            /* Ignore directories */
+            if (fdFile.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+                continue;
+
+            /* attempt to open the dynamic library as a filter library */
+            if (H5PL__open(path, search_params->type, search_params->id, found, plugin_info) < 0)
+                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "search in directory failed")
+            if (*found)
+                HGOTO_DONE(SUCCEED)
+
+            path = (char *)H5MM_xfree(path);
+        }
+    } while (FindNextFileA(hFind, &fdFile));
+
+done:
+    if (hFind != INVALID_HANDLE_VALUE)
+        FindClose(hFind);
+    if (path)
+        path = (char *)H5MM_xfree(path);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__find_plugin_in_path() */
+#endif /* H5_HAVE_WIN32_API */
+
diff --git a/src/H5PLpkg.h b/src/H5PLpkg.h
index e356893..0d1c271 100644
--- a/src/H5PLpkg.h
+++ b/src/H5PLpkg.h
@@ -11,6 +11,12 @@
  * help@hdfgroup.org.                                                        *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
+/*
+ * Purpose: This file contains declarations which are visible only within
+ *          the H5PL package.  Source files outside the H5PL package should
+ *          include H5PLprivate.h instead.
+ */
+
 #if !(defined H5PL_FRIEND || defined H5PL_MODULE)
 #error "Do not include this file outside the H5PL package!"
 #endif
@@ -27,13 +33,92 @@
 /* Package Private Macros */
 /**************************/
 
-#define H5PL_MAX_PATH_NUM       16
+/* Whether to pre-load pathnames for plugin libraries */
+#define H5PL_DEFAULT_PATH       H5_DEFAULT_PLUGINDIR
+
+
+/****************************/
+/* Macros for supporting    */
+/* both Windows and POSIX   */
+/****************************/
+
+/*******************/
+/* Windows support */
+/*******************/
+/*
+ * SPECIAL WINDOWS NOTE
+ *
+ * Some of the Win32 API functions expand to fooA or fooW depending on
+ * whether UNICODE or _UNICODE are defined. You MUST explicitly use
+ * the A version of the functions to force char * behavior until we
+ * work out a scheme for proper Windows Unicode support.
+ *
+ * If you do not do this, people will be unable to incorporate our
+ * source code into their own CMake builds if they define UNICODE.
+ */
+#ifdef H5_HAVE_WIN32_API
+
+    /* The path separator on this platform */
+#   define H5PL_PATH_SEPARATOR      ";"
+
+    /* Handle for dynamic library */
+#   define H5PL_HANDLE HINSTANCE
+
+    /* Get a handle to a plugin library.  Windows: TEXT macro handles Unicode strings */
+#   define H5PL_OPEN_DLIB(S) LoadLibraryExA(S, NULL, LOAD_WITH_ALTERED_SEARCH_PATH)
+
+    /* Get the address of a symbol in dynamic library */
+#   define H5PL_GET_LIB_FUNC(H,N) GetProcAddress(H,N)
+
+    /* Close dynamic library */
+#   define H5PL_CLOSE_LIB(H) FreeLibrary(H)
+
+    /* Clear error - nothing to do */
+#   define H5PL_CLR_ERROR
+
+    /* maximum size for expanding env vars */
+#   define H5PL_EXPAND_BUFFER_SIZE 32767
+
+    typedef const void *(__cdecl *H5PL_get_plugin_info_t)(void);
+
+#else /* H5_HAVE_WIN32_API */
+
+    /*****************/
+    /* POSIX support */
+    /*****************/
+
+    /* The path separator on this platform */
+#   define H5PL_PATH_SEPARATOR     ":"
+
+    /* Handle for dynamic library */
+#   define H5PL_HANDLE void *
+
+    /* Get a handle to a plugin library.  Windows: TEXT macro handles Unicode strings */
+#   define H5PL_OPEN_DLIB(S) dlopen(S, RTLD_LAZY)
+
+    /* Get the address of a symbol in dynamic library */
+#   define H5PL_GET_LIB_FUNC(H,N) dlsym(H,N)
+
+    /* Close dynamic library */
+#   define H5PL_CLOSE_LIB(H) dlclose(H)
+
+    /* Clear error */
+#   define H5PL_CLR_ERROR HERROR(H5E_PLUGIN, H5E_CANTGET, "can't dlopen:%s", dlerror())
+
+    typedef const void *(*H5PL_get_plugin_info_t)(void);
+#endif /* H5_HAVE_WIN32_API */
 
 
 /****************************/
 /* Package Private Typedefs */
 /****************************/
 
+/* Data used to search for plugins */
+typedef struct H5PL_search_params_t {
+    H5PL_type_t     type;
+    int             id;
+} H5PL_search_params_t;
+
 
 /*****************************/
 /* Package Private Variables */
@@ -44,5 +129,31 @@
 /* Package Private Prototypes */
 /******************************/
 
+/* Accessors to global variables and flags */
+H5_DLL herr_t H5PL__get_plugin_control_mask(unsigned int *mask /*out*/);
+H5_DLL herr_t H5PL__set_plugin_control_mask(unsigned int mask);
+
+/* Plugin search and manipulation */
+H5_DLL herr_t H5PL__open(const char *libname, H5PL_type_t type, int id, hbool_t *success /*out*/, const void **plugin_info /*out*/);
+H5_DLL herr_t H5PL__close(H5PL_HANDLE handle);
+
+/* Plugin cache calls */
+H5_DLL herr_t H5PL__create_plugin_cache(void);
+H5_DLL herr_t H5PL__close_plugin_cache(hbool_t *already_closed /*out*/);
+H5_DLL herr_t H5PL__add_plugin(H5PL_type_t type, int id, H5PL_HANDLE handle);
+H5_DLL herr_t H5PL__find_plugin_in_cache(const H5PL_search_params_t *search_params, hbool_t *found /*out*/, const void **plugin_info /*out*/);
+
+/* Plugin search path calls */
+H5_DLL herr_t H5PL__create_path_table(void);
+H5_DLL herr_t H5PL__close_path_table(void);
+H5_DLL unsigned H5PL__get_num_paths(void);
+H5_DLL herr_t H5PL__append_path(const char *path);
+H5_DLL herr_t H5PL__prepend_path(const char *path);
+H5_DLL herr_t H5PL__replace_path(const char *path, unsigned int index);
+H5_DLL herr_t H5PL__insert_path(const char *path, unsigned int index);
+H5_DLL herr_t H5PL__remove_path(unsigned int index);
+H5_DLL const char *H5PL__get_path(unsigned int index);
+H5_DLL herr_t H5PL__find_plugin_in_path_table(const H5PL_search_params_t *search_params, hbool_t *found /*out*/, const void **plugin_info /*out*/);
+
 #endif /* _H5PLpkg_H */
 
diff --git a/src/H5PLplugin_cache.c b/src/H5PLplugin_cache.c
new file mode 100644
index 0000000..30a0798
--- /dev/null
+++ b/src/H5PLplugin_cache.c
@@ -0,0 +1,308 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5. The full HDF5 copyright notice, including      *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the COPYING file, which can be found at the root of the source code       *
+ * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * If you do not have access to either file, you may request a copy from     *
+ * help@hdfgroup.org.                                                        *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Purpose: Code to implement a plugin cache which stores information
+ *          about plugins which have already been loaded.
+ *
+ *          The plugin cache is implemented as a dynamic, global array which
+ *          will grow as new plugins are added. The capacity of the cache
+ *          never shrinks since plugins stay in memory once loaded.
+ *
+ *          Note that this functionality has absolutely nothing to do with
+ *          the metadata or chunk caches.
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#include "H5PLmodule.h"          /* This source code file is part of the H5PL module */
+
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"      /* Generic Functions            */
+#include "H5Eprivate.h"     /* Error handling               */
+#include "H5MMprivate.h"    /* Memory management            */
+#include "H5PLpkg.h"        /* Plugin                       */
+#include "H5Zprivate.h"     /* Filter pipeline              */
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+/* Initial capacity of the plugin cache */
+#define H5PL_INITIAL_CACHE_CAPACITY     16
+
+/* The amount to add to the capacity when the cache is full */
+#define H5PL_CACHE_CAPACITY_ADD         16
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+/* Type for the list of info for opened plugin libraries */
+typedef struct H5PL_plugin_t {
+    H5PL_type_t     type;           /* Plugin type          */
+    int             id;             /* ID for the plugin    */
+    H5PL_HANDLE     handle;         /* Plugin handle        */
+} H5PL_plugin_t;
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+static herr_t H5PL__expand_cache(void);
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+/* Cache for storing opened plugin libraries */
+static H5PL_plugin_t   *H5PL_cache_g = NULL;
+
+/* The number of stored plugins */
+static unsigned int     H5PL_num_plugins_g = 0;
+
+/* The capacity of the plugin cache */
+static unsigned int     H5PL_cache_capacity_g = 0;
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__create_plugin_cache
+ *
+ * Purpose:     Create the cache that will store plugins that have already
+ *              been loaded.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__create_plugin_cache(void)
+{
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    /* Allocate memory for the plugin cache */
+    H5PL_num_plugins_g = 0;
+
+    H5PL_cache_capacity_g = H5PL_INITIAL_CACHE_CAPACITY;
+
+    if (NULL == (H5PL_cache_g = (H5PL_plugin_t *)H5MM_calloc((size_t)H5PL_cache_capacity_g * sizeof(H5PL_plugin_t))))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for plugin cache")
+
+done:
+    /* Try to clean up on errors */
+    if (FAIL == ret_value) {
+        if (H5PL_cache_g)
+            H5PL_cache_g = (H5PL_plugin_t *)H5MM_xfree(H5PL_cache_g);
+        H5PL_cache_capacity_g = 0;
+    }
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__create_plugin_cache() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__close_plugin_cache
+ *
+ * Purpose:     Close the cache of plugins that have already been loaded,
+ *              closing all the plugins contained inside.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__close_plugin_cache(hbool_t *already_closed /*out*/)
+{
+    unsigned int    u;                      /* iterator */
+    herr_t          ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE_NOERR
+
+    /* Close opened dynamic libraries */
+    if (H5PL_cache_g) {
+
+        /* Close any cached plugins */
+        for (u = 0; u < H5PL_num_plugins_g; u++)
+            H5PL__close((H5PL_cache_g[u]).handle);
+
+        /* Free the cache array */
+        H5PL_cache_g = (H5PL_plugin_t *)H5MM_xfree(H5PL_cache_g);
+        H5PL_num_plugins_g = 0;
+        H5PL_cache_capacity_g = 0;
+
+        /* Note that actually closed the table (needed by package close call) */
+        *already_closed = FALSE;
+    }
+    else
+        *already_closed = TRUE;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__close_plugin_cache() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__expand_cache
+ *
+ * Purpose:     Expand the plugin cache when it's full.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5PL__expand_cache(void)
+{
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Update the capacity */
+    H5PL_cache_capacity_g += H5PL_CACHE_CAPACITY_ADD;
+
+    /* Resize the array */
+    if(NULL == (H5PL_cache_g = (H5PL_plugin_t *)H5MM_realloc(H5PL_cache_g, (size_t)H5PL_cache_capacity_g * sizeof(H5PL_plugin_t))))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "allocating additional memory for plugin cache failed")
+
+    /* Initialize the new memory */
+    HDmemset(H5PL_cache_g + H5PL_num_plugins_g, 0, (size_t)H5PL_CACHE_CAPACITY_ADD * sizeof(H5PL_plugin_t));
+
+done:
+    /* Set the cache capacity back if there were problems */
+    if (FAIL == ret_value)
+        H5PL_cache_capacity_g -= H5PL_CACHE_CAPACITY_ADD;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__expand_cache() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__add_plugin
+ *
+ * Purpose:     Add a plugin to the plugin cached.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__add_plugin(H5PL_type_t type, int id, H5PL_HANDLE handle)
+{
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    /* Expand the cache if it is too small */
+    if (H5PL_num_plugins_g >= H5PL_cache_capacity_g)
+        if (H5PL__expand_cache() < 0)
+            HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't expand plugin cache")
+
+    /* Store the plugin info and bump the # of plugins */
+    H5PL_cache_g[H5PL_num_plugins_g].type       = type;
+    H5PL_cache_g[H5PL_num_plugins_g].id         = id;
+    H5PL_cache_g[H5PL_num_plugins_g].handle     = handle;
+
+    H5PL_num_plugins_g++;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__add_plugin() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PL__find_plugin_in_cache
+ *
+ * Purpose:     Attempts to find a matching plugin from the cache.
+ *
+ *              The 'found' parameter will be set appropriately.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PL__find_plugin_in_cache(const H5PL_search_params_t *search_params, hbool_t *found, const void **plugin_info)
+{
+    unsigned int    u;                          /* iterator */
+    herr_t          ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args - Just assert on package functions */
+    HDassert(search_params);
+    HDassert(found);
+    HDassert(plugin_info);
+
+    /* Initialize output parameters */
+    *found = FALSE;
+    *plugin_info = NULL;
+
+    /* Loop over all the plugins, looking for one that matches */
+    for (u = 0; u < H5PL_num_plugins_g; u++) {
+
+        /* If the plugin type (filter, etc.) and ID match, query the plugin for its info */
+        if ((search_params->type == (H5PL_cache_g[u]).type) && (search_params->id == (H5PL_cache_g[u]).id)) {
+
+            H5PL_get_plugin_info_t      get_plugin_info_function;
+            const H5Z_class2_t          *filter_info;
+
+            /* Get the "get plugin info" function from the plugin.
+             *
+             * See the other use of H5PL_GET_LIB_FUNC() for an explanation
+             * for why we disable -Wpedantic here.
+             */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+            if (NULL == (get_plugin_info_function = (H5PL_get_plugin_info_t)H5PL_GET_LIB_FUNC((H5PL_cache_g[u]).handle, "H5PLget_plugin_info")))
+                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "can't get function for H5PLget_plugin_info")
+#pragma GCC diagnostic pop
+
+            /* Call the "get plugin info" function */
+            if (NULL == (filter_info = (const H5Z_class2_t *)(*get_plugin_info_function)()))
+                HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "can't get plugin info")
+
+            /* Set output parameters */
+            *found = TRUE;
+            *plugin_info = filter_info;
+
+            /* No need to continue processing */
+            break;
+
+        } /* end if */
+
+    } /* end for */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PL__find_plugin_in_cache() */
+
diff --git a/src/H5PLprivate.h b/src/H5PLprivate.h
index 0ab8f8c..bc12e64 100644
--- a/src/H5PLprivate.h
+++ b/src/H5PLprivate.h
@@ -10,8 +10,8 @@
  * help@hdfgroup.org.                                                        *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
-/* Programmer:  Raymond Lu <songyulu@hdfgroup.org>
- *              13 February 2013
+/*
+ * This file contains private information about the H5PL module
  */
 
 #ifndef _H5PLprivate_H
diff --git a/src/H5PLpublic.h b/src/H5PLpublic.h
index 9ce1fca..3b36ccd 100644
--- a/src/H5PLpublic.h
+++ b/src/H5PLpublic.h
@@ -10,8 +10,8 @@
  * help@hdfgroup.org.                                                        *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
-/* Programmer:  Raymond Lu <songyulu@hdfgroup.org>
- *              13 February 2013
+/*
+ * This file contains public declarations for the H5PL module.
  */
 
 #ifndef _H5PLpublic_H
@@ -24,31 +24,35 @@
 /* Public Typedefs */
 /*******************/
 
+/* Special string to indicate no plugin loading.
+ */
+#define H5PL_NO_PLUGIN          "::"
+
 /* Plugin type used by the plugin library */
 typedef enum H5PL_type_t {
-    H5PL_TYPE_ERROR        = -1,  /*error                    */
-    H5PL_TYPE_FILTER       = 0,   /*filter                   */
-    H5PL_TYPE_NONE         = 1    /*this must be last!       */
+    H5PL_TYPE_ERROR         = -1,   /* Error                    */
+    H5PL_TYPE_FILTER        = 0,    /* Filter                   */
+    H5PL_TYPE_NONE          = 1     /* This must be last!       */
 } H5PL_type_t;
 
 /* Common dynamic plugin type flags used by the set/get_loading_state functions */
-#define H5PL_FILTER_PLUGIN 0x0001
-#define H5PL_ALL_PLUGIN 0xFFFF
+#define H5PL_FILTER_PLUGIN      0x0001
+#define H5PL_ALL_PLUGIN         0xFFFF
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /* plugin state */
-H5_DLL herr_t H5PLset_loading_state(unsigned int plugin_type);
-H5_DLL herr_t H5PLget_loading_state(unsigned int *plugin_type/*out*/);
-H5_DLL herr_t H5PLappend(const char *plugin_path);
-H5_DLL herr_t H5PLprepend(const char *plugin_path);
-H5_DLL herr_t H5PLreplace(const char *plugin_path, unsigned int index);
-H5_DLL herr_t H5PLinsert(const char *plugin_path, unsigned int index);
+H5_DLL herr_t H5PLset_loading_state(unsigned int plugin_control_mask);
+H5_DLL herr_t H5PLget_loading_state(unsigned int *plugin_control_mask /*out*/);
+H5_DLL herr_t H5PLappend(const char *search_path);
+H5_DLL herr_t H5PLprepend(const char *search_path);
+H5_DLL herr_t H5PLreplace(const char *search_path, unsigned int index);
+H5_DLL herr_t H5PLinsert(const char *search_path, unsigned int index);
 H5_DLL herr_t H5PLremove(unsigned int index);
-H5_DLL ssize_t H5PLget(unsigned int index, char *pathname/*out*/, size_t size);
-H5_DLL herr_t H5PLsize(unsigned int *listsize/*out*/);
+H5_DLL ssize_t H5PLget(unsigned int index, char *path_buf /*out*/, size_t buf_size);
+H5_DLL herr_t H5PLsize(unsigned int *num_paths /*out*/);
 
 #ifdef __cplusplus
 }
diff --git a/src/H5system.c b/src/H5system.c
index 7e25540..a1cdf19 100644
--- a/src/H5system.c
+++ b/src/H5system.c
@@ -1237,3 +1237,49 @@ H5_get_time(void)
 } /* end H5_get_time() */
 
 
+#ifdef H5_HAVE_WIN32_API
+
+#define H5_WIN32_ENV_VAR_BUFFER_SIZE    32767
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5_expand_windows_env_vars()
+ *
+ * Purpose:     Replaces windows environment variables of the form %foo%
+ *              with user-specific values.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5_expand_windows_env_vars(char **env_var)
+{
+    long    n_chars = 0;
+    char   *temp_buf = NULL;
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Allocate buffer for expanded environment variable string */
+    if (NULL == (temp_buf = (char *)H5MM_calloc((size_t)H5_WIN32_ENV_VAR_BUFFER_SIZE)))
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTALLOC, FAIL, "can't allocate memory for expanded path")
+
+    /* Expand the environment variable string */
+    if ((n_chars = ExpandEnvironmentStringsA(*env_var, temp_buf, H5_WIN32_ENV_VAR_BUFFER_SIZE)) > H5_WIN32_ENV_VAR_BUFFER_SIZE)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_NOSPACE, FAIL, "expanded path is too long")
+
+    if (0 == n_chars)
+        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "failed to expand path")
+
+    *env_var = (char *)H5MM_xfree(*env_var);
+    *env_var = temp_buf;
+
+done:
+    if (FAIL == ret_value && temp_buf)
+        temp_buf = (char *)H5MM_xfree(temp_buf);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5_expand_windows_env_vars() */
+#endif /* H5_HAVE_WIN32_API */
+
diff --git a/src/H5win32defs.h b/src/H5win32defs.h
index 97f7179..4522228 100644
--- a/src/H5win32defs.h
+++ b/src/H5win32defs.h
@@ -119,6 +119,7 @@ extern "C" {
     H5_DLL int c99_snprintf(char* str, size_t size, const char* format, ...);
     H5_DLL int c99_vsnprintf(char* str, size_t size, const char* format, va_list ap);
     H5_DLL int Wnanosleep(const struct timespec *req, struct timespec *rem);
+    H5_DLL herr_t H5_expand_windows_env_vars(char **env_var);
 
     /* Round functions only needed for VS2012 and earlier.
      * They are always built to ensure they don't go stale and
diff --git a/src/Makefile.am b/src/Makefile.am
index 0b664a7..9a64717 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -97,7 +97,7 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5Pgcpl.c H5Pint.c \
         H5Plapl.c H5Plcpl.c H5Pocpl.c H5Pocpypl.c H5Pstrcpl.c H5Ptest.c \
         H5PB.c \
-        H5PL.c \
+        H5PL.c H5PLint.c H5PLpath.c H5PLplugin_cache.c \
         H5R.c H5Rdeprec.c \
         H5UC.c \
         H5RS.c \
diff --git a/test/plugin.c b/test/plugin.c
index 3034c0b..ea199f6 100644
--- a/test/plugin.c
+++ b/test/plugin.c
@@ -10,9 +10,6 @@
  * help@hdfgroup.org.                                                        *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 /*
- * Programmer:    Raymond Lu
- *        13 February 2013
- *
  * Purpose:    Tests the plugin module (H5PL)
  */
 
@@ -660,13 +657,10 @@ error:
 /*-------------------------------------------------------------------------
  * Function:    test_groups_with_filters
  *
- * Purpose:    Tests opening group with dynamically loaded filters
- *
- * Return:    Success:    0
- *        Failure:    -1
+ * Purpose:     Tests opening group with dynamically loaded filters
  *
- * Programmer:    Raymond Lu
- *              1 April 2013
+ * Return:      Success:    0
+ *              Failure:    -1
  *
  *-------------------------------------------------------------------------
  */
@@ -710,264 +704,388 @@ error:
 
 
 /*-------------------------------------------------------------------------
- * Function:  test_filter_path_apis
+ * Function:  test_path_api_calls
  *
- * Purpose:   Tests accessing the path table for dynamically loaded filters
+ * Purpose:   Tests the H5PL API calls that manipulate the plugin search
+ *            paths.
  *
- * Return:    Success:    0
- *            Failure:    -1
+ * Return:    SUCCEED/FAIL
+ * 
  *-------------------------------------------------------------------------
  */
 static herr_t
-test_filter_path_apis(void)
+test_path_api_calls(void)
 {
-    herr_t       ret_value = -1;
-    unsigned int i;
-    unsigned int ndx;
+    unsigned int n_starting_paths;
+    unsigned int u;                 
+    unsigned int n_paths;
     herr_t       ret;
-    ssize_t      pathlen = -1;
-    char         pathname[256];
-    char         tempname[256];
+    ssize_t      path_len = -1;
+    char         path[256];
+    char         temp_name[256];
 
     HDputs("Testing access to the filter path table");
 
-    if(H5Zfilter_avail(H5Z_FILTER_DYNLIB1) != TRUE) TEST_ERROR
+    if(H5Zfilter_avail(H5Z_FILTER_DYNLIB1) != TRUE)
+        TEST_ERROR
+
+    /* Set the number of paths to create for this test.
+     *
+     * This should be set high enough to ensure that at least one array
+     * expansion will take place. See H5PLpath.c for details.
+     */
+    n_starting_paths = 42;
 
+    /* Check that initialization is correct */
     TESTING("    initialize");
-    H5PLsize(&ndx);
-    if(ndx!=2) TEST_ERROR
+
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+    if(n_paths != 2)
+        TEST_ERROR
+
     PASSED();
 
+    /****************/
+    /* H5PLremove() */
+    /****************/
+
+    /* Remove all the current paths */
     TESTING("    remove");
-    /* Remove all existing paths*/
-    for(i=ndx; i > 0; i--)
-        if(H5PLremove(i-1) < 0) {
-            HDfprintf(stderr,"    at %d: %s\n", i, pathname);
+
+    /* Get the current size */
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+
+    /* Remove all existing paths */
+    for(u = n_paths; u > 0; u--)
+        if(H5PLremove(u-1) < 0) {
+            HDfprintf(stderr,"    at %u: %s\n", u, path);
             TEST_ERROR
-        } /* end if */
+        }
+
     /* Verify the table is empty */
-    H5PLsize(&ndx);
-    if(ndx > 0) TEST_ERROR
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+    if(n_paths > 0)
+        TEST_ERROR
+
     PASSED();
 
-    TESTING("    remove (exceed min)");
-    /* Exceed the min path removal */
+
+    TESTING("    remove (index 0 in empty table)");
+
+    /* Try to remove index zero in an empty list (SHOULD FAIL) */
     H5E_BEGIN_TRY {
         ret = H5PLremove(0);
     } H5E_END_TRY
-    if(ret >= 0) TEST_ERROR
+    if(ret >= 0)
+        TEST_ERROR
+
     PASSED();
 
+
+    /****************/
+    /* H5PLappend() */
+    /****************/
+
     TESTING("    append");
-    /* Create multiple paths to fill table */
-    for(i=0; i < H5PL_MAX_PATH_NUM; i++) {
-        HDsprintf(pathname, "a_path_%d", i);
-        if(H5PLappend(pathname) < 0) {
-            HDfprintf(stderr,"    at %d: %s\n", i, pathname);
+
+    /* Add a bunch of paths to the path table */
+    for(u = 0; u < n_starting_paths; u++) {
+        HDsprintf(path, "a_path_%u", u);
+        if(H5PLappend(path) < 0) {
+            HDfprintf(stderr,"    at %u: %s\n", u, path);
             TEST_ERROR
         }
     }
-    /* Verify the table is full */
-    H5PLsize(&ndx);
-    if(ndx != H5PL_MAX_PATH_NUM) TEST_ERROR
-    PASSED();
 
-    TESTING("    append (exceed)");
-    /* Exceed the max path append */
-    H5E_BEGIN_TRY {
-        HDsprintf(pathname, "a_path_%d", H5PL_MAX_PATH_NUM);
-        ret = H5PLappend(pathname);
-    } H5E_END_TRY
-    if(ret >= 0) TEST_ERROR
     PASSED();
 
-    TESTING("    remove (exceed max)");
-    /* Exceed the max path removal */
+
+    /**********************/
+    /* H5PLremove() again */
+    /**********************/
+
+    TESTING("    remove (index too high)");
+
+    /* Try to remove a path where the index is beyond the table capacity (SHOULD FAIL) */
     H5E_BEGIN_TRY {
-        ret = H5PLremove(H5PL_MAX_PATH_NUM);
+        ret = H5PLremove(n_starting_paths);
     } H5E_END_TRY
-    if(ret >= 0) TEST_ERROR
+
+    if(ret >= 0)
+        TEST_ERROR
+
     PASSED();
 
+
+    /*************/
+    /* H5PLget() */
+    /*************/
+
     TESTING("    get (path name)");
-    if((pathlen = H5PLget(0, NULL, 0)) <= 0) {
+
+    /* Get the path length by passing in NULL */
+    if((path_len = H5PLget(0, NULL, 0)) <= 0) {
         HDfprintf(stderr,"    get path 0 length failed\n");
         TEST_ERROR
     }
-    if(pathlen != 8) TEST_ERROR
+    if(path_len != 8)
+        TEST_ERROR
 
-    if((pathlen = H5PLget(0, pathname, 256)) <= 0) {
-        HDfprintf(stderr,"    get 0 len: %d : %s\n", pathlen, pathname);
+    /* Get the path */
+    if((path_len = H5PLget(0, path, 256)) <= 0) {
+        HDfprintf(stderr,"    get 0 len: %u : %s\n", path_len, path);
         TEST_ERROR
     }
-    if(HDstrcmp(pathname, "a_path_0") != 0) {
-        HDfprintf(stderr,"    get 0: %s\n", pathname);
+    if(HDstrcmp(path, "a_path_0") != 0) {
+        HDfprintf(stderr,"    get 0: %s\n", path);
         TEST_ERROR
     }
+
     PASSED();
 
-    TESTING("    get (bounds)");
-    if((pathlen = H5PLget(1, pathname, 256)) <= 0) TEST_ERROR
-    if(HDstrcmp(pathname, "a_path_1") != 0) {
-        HDfprintf(stderr,"    get 1: %s\n", pathname);
+
+    TESTING("    get (high and low indices)");
+
+    /* Get path at index 1 */
+    if((path_len = H5PLget(1, path, 256)) <= 0)
+        TEST_ERROR
+    if(HDstrcmp(path, "a_path_1") != 0) {
+        HDfprintf(stderr,"    get 1: %s\n", path);
         TEST_ERROR
     }
-    if((pathlen = H5PLget(H5PL_MAX_PATH_NUM - 1, pathname, 256)) <= 0) TEST_ERROR
-    HDsprintf(tempname, "a_path_%d", H5PL_MAX_PATH_NUM - 1);
-    if(HDstrcmp(pathname, tempname) != 0) {
-        HDfprintf(stderr,"    get %d: %s\n", H5PL_MAX_PATH_NUM - 1, pathname);
+
+    /* Get path at the last index */
+    if((path_len = H5PLget(n_starting_paths - 1, path, 256)) <= 0)
+        TEST_ERROR
+    HDsprintf(temp_name, "a_path_%u", n_starting_paths - 1);
+    if(HDstrcmp(path, temp_name) != 0) {
+        HDfprintf(stderr,"    get %u: %s\n", n_starting_paths - 1, path);
         TEST_ERROR
     }
+
     PASSED();
 
-    TESTING("    get (bounds exceed)");
+
+    TESTING("    get (index too high)");
+
+    /* Get path at the last + 1 index (SHOULD FAIL) */
     H5E_BEGIN_TRY {
-        pathlen = H5PLget(H5PL_MAX_PATH_NUM, NULL, 0);
+        path_len = H5PLget(n_starting_paths, NULL, 0);
     } H5E_END_TRY
-    if(pathlen > 0) TEST_ERROR
+    if(path_len > 0)
+        TEST_ERROR
+
     PASSED();
 
-    TESTING("    remove (verify for prepend)");
-    /* Remove one path*/
-    if(H5PLremove(8) < 0) TEST_ERROR
+
+    /*****************/
+    /* H5PLprepend() */
+    /*****************/
+
+    /* We'll remove a path at an arbitrary index and then
+     * prepend a new path.
+     */
+
+    TESTING("    remove (arbitrary index 1)");
+
+    /* Remove one path */
+    if(H5PLremove(8) < 0)
+        TEST_ERROR
 
     /* Verify that the entries were moved */
-    if((pathlen = H5PLget(8, pathname, 256)) <= 0) TEST_ERROR
-    if(HDstrcmp(pathname, "a_path_9") != 0) {
-        HDfprintf(stderr,"    get 8: %s\n", pathname);
+    if((path_len = H5PLget(8, path, 256)) <= 0)
+        TEST_ERROR
+    if(HDstrcmp(path, "a_path_9") != 0) {
+        HDfprintf(stderr,"    get 8: %s\n", path);
         TEST_ERROR
     }
+
+    /* Verify the table shrank */
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+    if(n_paths != n_starting_paths - 1)
+        TEST_ERROR
+
     PASSED();
 
-    /* Verify the table is not full */
-    H5PLsize(&ndx);
-    if (ndx != H5PL_MAX_PATH_NUM - 1) TEST_ERROR
 
     TESTING("    prepend");
-    /* Prepend one path*/
-    HDsprintf(pathname, "a_path_%d", H5PL_MAX_PATH_NUM + 1);
-    if(H5PLprepend(pathname) < 0) {
-        HDfprintf(stderr,"    prepend %d: %s\n", H5PL_MAX_PATH_NUM + 1, pathname);
+
+    /* Prepend one path */
+    HDsprintf(path, "a_path_%d", n_starting_paths + 1);
+    if(H5PLprepend(path) < 0) {
+        HDfprintf(stderr,"    prepend %u: %s\n", n_starting_paths + 1, path);
         TEST_ERROR
     }
 
-    /* Verify the table is full */
-    H5PLsize(&ndx);
-    if(ndx != H5PL_MAX_PATH_NUM) TEST_ERROR
+    /* Verify the table increased */
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+    if(n_paths != n_starting_paths)
+        TEST_ERROR
 
     /* Verify that the entries were moved */
-    if(H5PLget(8, pathname, 256) <= 0) TEST_ERROR
-    if(HDstrcmp(pathname, "a_path_7") != 0) {
-        HDfprintf(stderr,"    get 8: %s\n", pathname);
+    if(H5PLget(8, path, 256) <= 0)
+        TEST_ERROR
+    if(HDstrcmp(path, "a_path_7") != 0) {
+        HDfprintf(stderr,"    get 8: %s\n", path);
         TEST_ERROR
     }
-    if(H5PLget(0, pathname, 256) <= 0) TEST_ERROR
-    HDsprintf(tempname, "a_path_%d", H5PL_MAX_PATH_NUM + 1);
-    if(HDstrcmp(pathname, tempname) != 0) {
-        HDfprintf(stderr,"    get 0: %s\n", pathname);
+
+    /* Verify that the path was inserted at index zero */
+    if(H5PLget(0, path, 256) <= 0)
+        TEST_ERROR
+    HDsprintf(temp_name, "a_path_%d", n_starting_paths + 1);
+    if(HDstrcmp(path, temp_name) != 0) {
+        HDfprintf(stderr,"    get 0: %s\n", path);
         TEST_ERROR
     }
-    PASSED();
 
-    TESTING("    prepend (exceed)");
-    /* Exceed the max path prepend */
-    H5E_BEGIN_TRY {
-        HDsprintf(pathname, "a_path_%d", H5PL_MAX_PATH_NUM + 2);
-        ret = H5PLprepend(pathname);
-    } H5E_END_TRY
-    if(ret >= 0) TEST_ERROR
     PASSED();
 
+
+    /*****************/
+    /* H5PLreplace() */
+    /*****************/
+
     TESTING("    replace");
-    /* Replace one path*/
-    HDsprintf(pathname, "a_path_%d", H5PL_MAX_PATH_NUM + 4);
-    if(H5PLreplace(pathname, 1) < 0) {
-        HDfprintf(stderr,"    replace 1: %s\n", pathname);
+
+    /* Replace one path at index 1 */
+    HDsprintf(path, "a_path_%u", n_starting_paths + 4);
+    if(H5PLreplace(path, 1) < 0) {
+        HDfprintf(stderr,"    replace 1: %s\n", path);
         TEST_ERROR
     }
 
-    /* Verify the table is full */
-    H5PLsize(&ndx);
-    if(ndx != H5PL_MAX_PATH_NUM) TEST_ERROR
+    /* Verify the table size remained the same */
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+    if(n_paths != n_starting_paths)
+        TEST_ERROR
+
+    /* Verify that the entries were not moved by
+     * inspecting the paths at indices +/- 1.
+     */
 
-    /* Verify that the entries were not moved */
-    if(H5PLget(0, pathname, 256) <= 0) TEST_ERROR
-    HDsprintf(tempname, "a_path_%d", H5PL_MAX_PATH_NUM + 1);
-    if(HDstrcmp(pathname, tempname) != 0) {
-        HDfprintf(stderr,"    get 0: %s\n", pathname);
+    /* Check path at index 0 */
+    if(H5PLget(0, path, 256) <= 0)
+        TEST_ERROR
+    HDsprintf(temp_name, "a_path_%u", n_starting_paths + 1);
+    if(HDstrcmp(path, temp_name) != 0) {
+        HDfprintf(stderr,"    get 0: %s\n", path);
         TEST_ERROR
     }
-    if(H5PLget(2, pathname, 256) <= 0) TEST_ERROR
-    if(HDstrcmp(pathname, "a_path_1") != 0) {
-        HDfprintf(stderr,"    get 2: %s\n", pathname);
+
+    /* Check path at index 2 */
+    if(H5PLget(2, path, 256) <= 0)
+        TEST_ERROR
+    if(HDstrcmp(path, "a_path_1") != 0) {
+        HDfprintf(stderr,"    get 2: %s\n", path);
         TEST_ERROR
     }
+
     PASSED();
 
-    TESTING("    remove (verify for insert)");
-    /* Remove one path*/
-    if(H5PLremove(4) < 0) TEST_ERROR
+
+    /****************/
+    /* H5PLinsert() */
+    /****************/
+
+    /* We'll remove a path at an arbitrary index and then
+     * insert a new path.
+     */
+
+    TESTING("    remove (arbitrary index 2)");
+
+    /* Remove one path */
+    if(H5PLremove(4) < 0)
+        TEST_ERROR
 
     /* Verify that the entries were moved */
-    if(H5PLget(4, pathname, 256) <= 0) TEST_ERROR
-    if(HDstrcmp(pathname, "a_path_4") != 0) {
-        HDfprintf(stderr,"    get 4: %s\n", pathname);
+    if(H5PLget(4, path, 256) <= 0)
+        TEST_ERROR
+    if(HDstrcmp(path, "a_path_4") != 0) {
+        HDfprintf(stderr,"    get 4: %s\n", path);
         TEST_ERROR
     }
+
+    /* Verify the table size */
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+    if(n_paths != n_starting_paths - 1)
+        TEST_ERROR
     PASSED();
 
-    /* Verify the table is not full */
-    H5PLsize(&ndx);
-    if(ndx != 15) TEST_ERROR
 
     TESTING("    insert");
-    /* Insert one path*/
-    HDsprintf(pathname, "a_path_%d", H5PL_MAX_PATH_NUM + 5);
-    if(H5PLinsert(pathname, 3) < 0) {
-        HDfprintf(stderr,"    insert 3: %s\n", pathname);
+
+    /* Insert one path at index 3*/
+    HDsprintf(path, "a_path_%d", n_starting_paths + 5);
+    if(H5PLinsert(path, 3) < 0) {
+        HDfprintf(stderr,"    insert 3: %s\n", path);
         TEST_ERROR
     }
 
     /* Verify that the entries were moved */
-    if(H5PLget(4, pathname, 256) <= 0) TEST_ERROR
-    if(HDstrcmp(pathname, "a_path_2") != 0) {
-        HDfprintf(stderr,"    get 4: %s\n", pathname);
+    if(H5PLget(4, path, 256) <= 0)
+        TEST_ERROR
+    if(HDstrcmp(path, "a_path_2") != 0) {
+        HDfprintf(stderr,"    get 4: %s\n", path);
         TEST_ERROR
     }
+
+    /* Verify the table size increased */
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+    if(n_paths != n_starting_paths)
+        TEST_ERROR
+
     PASSED();
 
-    /* Verify the table is full */
-    H5PLsize(&ndx);
-    if(ndx != H5PL_MAX_PATH_NUM) TEST_ERROR
 
-    TESTING("    insert (exceed)");
-    /* Exceed the max path insert */
-    H5E_BEGIN_TRY {
-        HDsprintf(pathname, "a_path_%d", H5PL_MAX_PATH_NUM + 6);
-        ret = H5PLinsert(pathname, 12);
-    } H5E_END_TRY
-    if(ret >= 0) TEST_ERROR
+    /****************/
+    /* H5PLremove() */
+    /****************/
+
+    /* Remove all the current paths */
+    TESTING("    remove (all)");
+
+    /* Get the current size */
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+
+    /* Remove all existing paths */
+    for(u = n_paths; u > 0; u--)
+        if(H5PLremove(u-1) < 0) {
+            HDfprintf(stderr,"    at %u: %s\n", u, path);
+            TEST_ERROR
+        }
+
+    /* Verify the table is empty */
+    if(H5PLsize(&n_paths) < 0)
+        TEST_ERROR
+    if(n_paths > 0)
+        TEST_ERROR
 
     PASSED();
 
-    ret_value = 0;
+
+    return SUCCEED;
 
 error:
-    return ret_value;
-}
+    return FAIL;
+} /* end test_path_api_calls() */
 
 
 /*-------------------------------------------------------------------------
  * Function:    main
  *
- * Purpose:    Tests the plugin module (H5PL)
+ * Purpose:     Tests the plugin module (H5PL)
  *
- * Return:    Success:    exit(EXIT_SUCCESS)
- *
- *        Failure:    exit(EXIT_FAILURE)
- *
- * Programmer:    Raymond Lu
- *        14 March 2013
+ * Return:      EXIT_SUCCESS/EXIT_FAILURE
  *
  *-------------------------------------------------------------------------
  */
@@ -987,37 +1105,44 @@ main(void)
 
     /* Testing setup */
     h5_reset();
-    fapl = h5_fileaccess();
+
+    if ((fapl = h5_fileaccess()) < 0)
+        TEST_ERROR
 
     /* Turn off the chunk cache, so all the chunks are immediately written to disk */
-    if(H5Pget_cache(fapl, &mdc_nelmts, &rdcc_nelmts, &rdcc_nbytes, &rdcc_w0) < 0) TEST_ERROR
+    if (H5Pget_cache(fapl, &mdc_nelmts, &rdcc_nelmts, &rdcc_nbytes, &rdcc_w0) < 0)
+        TEST_ERROR
     rdcc_nbytes = 0;
-    if(H5Pset_cache(fapl, mdc_nelmts, rdcc_nelmts, rdcc_nbytes, rdcc_w0) < 0) TEST_ERROR
+    if (H5Pset_cache(fapl, mdc_nelmts, rdcc_nelmts, rdcc_nbytes, rdcc_w0) < 0)
+        TEST_ERROR
 
     /* Copy the file access property list */
-    if((fapl2 = H5Pcopy(fapl)) < 0) TEST_ERROR
+    if ((fapl2 = H5Pcopy(fapl)) < 0)
+        TEST_ERROR
 
     /* Set the "use the latest version of the format" bounds for creating objects in the file */
-    if(H5Pset_libver_bounds(fapl2, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0) TEST_ERROR
+    if (H5Pset_libver_bounds(fapl2, H5F_LIBVER_LATEST, H5F_LIBVER_LATEST) < 0)
+        TEST_ERROR
 
-    h5_fixname(FILENAME[0], fapl, filename, sizeof filename);
+    h5_fixname(FILENAME[0], fapl, filename, sizeof(filename));
 
     /* Test with old & new format groups */
-    for(new_format = FALSE; new_format <= TRUE; new_format++) {
+    for (new_format = FALSE; new_format <= TRUE; new_format++) {
         hid_t my_fapl;
 
         /* Set the FAPL for the type of format */
-        if(new_format) {
+        if (new_format) {
             HDputs("\nTesting with new file format:");
             my_fapl = fapl2;
-        } /* end if */
+        }
         else {
             HDputs("Testing with old file format:");
             my_fapl = fapl;
-        } /* end else */
+        }
 
         /* Create the file for this test */
-        if((file = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, my_fapl)) < 0) TEST_ERROR
+        if ((file = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, my_fapl)) < 0)
+            TEST_ERROR
 
         /* Test dynamically loaded filters for chunked dataset */
         nerrors += (test_filters_for_datasets(file) < 0    ? 1 : 0);
@@ -1025,12 +1150,15 @@ main(void)
         /* Test dynamically loaded filters for groups */
         nerrors += (test_filters_for_groups(file) < 0 ? 1 : 0);
 
-        if(H5Fclose(file) < 0) TEST_ERROR
+        if (H5Fclose(file) < 0)
+            TEST_ERROR
     } /* end for */
 
     /* Close FAPL */
-    if(H5Pclose(fapl2) < 0) TEST_ERROR
-    if(H5Pclose(fapl) < 0) TEST_ERROR
+    if (H5Pclose(fapl2) < 0)
+        TEST_ERROR
+    if (H5Pclose(fapl) < 0)
+        TEST_ERROR
 
     /* Restore the default error handler (set in h5_reset()) */
     h5_restore_err();
@@ -1039,10 +1167,12 @@ main(void)
 
     /* Close the library so that all loaded plugin libraries are unloaded */
     h5_reset();
-    fapl = h5_fileaccess();
+    if ((fapl = h5_fileaccess()) < 0)
+        TEST_ERROR
 
     /* Reopen the file for testing data reading */
-    if((file = H5Fopen(filename, H5F_ACC_RDONLY, fapl)) < 0) TEST_ERROR
+    if ((file = H5Fopen(filename, H5F_ACC_RDONLY, fapl)) < 0)
+        TEST_ERROR
 
     /* Read the data with filters */
     nerrors += (test_read_with_filters(file) < 0 ? 1 : 0);
@@ -1055,29 +1185,33 @@ main(void)
 
     /* Close the library so that all loaded plugin libraries are unloaded */
     h5_reset();
-    fapl = h5_fileaccess();
+    if ((fapl = h5_fileaccess()) < 0)
+        TEST_ERROR
 
     /* Reopen the file for testing data reading */
-    if((file = H5Fopen(filename, H5F_ACC_RDONLY, fapl)) < 0) TEST_ERROR
+    if ((file = H5Fopen(filename, H5F_ACC_RDONLY, fapl)) < 0)
+        TEST_ERROR
 
     /* Read the data with disabled filters */
     nerrors += (test_noread_with_filters(file) < 0  ? 1 : 0);
 
-    if(H5Fclose(file) < 0) TEST_ERROR
+    if (H5Fclose(file) < 0)
+        TEST_ERROR
 
     /* Test the APIs for access to the filter plugin path table */
-    nerrors += (test_filter_path_apis() < 0  ? 1 : 0);
+    nerrors += (test_path_api_calls() < 0  ? 1 : 0);
 
-    if(nerrors) TEST_ERROR
+    if (nerrors)
+        TEST_ERROR
 
     HDprintf("All plugin tests passed.\n");
     h5_cleanup(FILENAME, fapl);
 
-    return 0;
+    HDexit(EXIT_SUCCESS);
 
 error:
     nerrors = MAX(1, nerrors);
     HDprintf("***** %d PLUGIN TEST%s FAILED! *****\n", nerrors, 1 == nerrors ? "" : "S");
-    return 1;
-}
+    HDexit(EXIT_FAILURE);
+} /* end main() */