Merge pull request #2116 in HDFFV/hdf5 from ~JSOUMAGNE/hdf5:hdf5-1_12-ref_token to hdf5_1_12

* commit '1aea46ce671daf2828ac65d0b8551b369f497922':
  Fix H5VL_token_t type and fix H5VL_loc_by_token to use H5VL_token_t *
  Change hdset_reg_ref_t and H5R_ref_t from arrays of unsigned char to structs containing those arrays.  Encapsulating the arrays in this way makes it easier to write and think about pointers to these types, casts to/from these types, etc.
  H5R: fix H5Tconv to check for null references
  Remove H5VL_NATIVE_FILE_GET_FILE_ID and add H5VL_OBJECT_GET_FILE

19 files changed, 429 insertions, 180 deletions

diff --git a/src/H5Fint.c b/src/H5Fint.c
index 435c1be..153ec2f 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -3654,9 +3654,9 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5F__get_file_id
+ * Function:    H5F_get_file_id
  *
- * Purpose:     The package version of H5Iget_file_id(), obtains the file
+ * Purpose:     The private version of H5Iget_file_id(), obtains the file
  *              ID given an object ID.
  *
  * Return:      Success:    The file ID associated with the object
@@ -3665,22 +3665,31 @@ done:
  *-------------------------------------------------------------------------
  */
 hid_t
-H5F__get_file_id(H5F_t *file, hbool_t app_ref)
+H5F_get_file_id(H5VL_object_t *vol_obj, H5I_type_t obj_type, hbool_t app_ref)
 {
-    hid_t file_id = H5I_INVALID_HID;    /* File ID */
-    hid_t ret_value = H5I_INVALID_HID;  /* Return value */
+    void *vol_obj_file = NULL;                  /* File object pointer */
+    H5VL_loc_params_t loc_params;               /* Location parameters */
+    hid_t           file_id = H5I_INVALID_HID;  /* File ID for object */
+    hid_t           ret_value = H5I_INVALID_HID; /* Return value */
 
-    FUNC_ENTER_PACKAGE
+    FUNC_ENTER_NOAPI(H5I_INVALID_HID)
+
+    /* Set location parameters */
+    loc_params.type = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = obj_type;
+
+    /* Retrieve VOL file from object */
+    if(H5VL_object_get(vol_obj, &loc_params, H5VL_OBJECT_GET_FILE, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &vol_obj_file) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, H5I_INVALID_HID, "can't retrieve file from object")
 
     /* Check if the file's ID already exists */
-    if(H5I_find_id(file, H5I_FILE, &file_id) < 0)
+    if(H5I_find_id(vol_obj_file, H5I_FILE, &file_id) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTGET, H5I_INVALID_HID, "getting file ID failed")
 
     /* If the ID does not exist, register it with the VOL connector */
     if(H5I_INVALID_HID == file_id) {
-        if((file_id = H5VL_wrap_register(H5I_FILE, file, app_ref)) < 0)
+        if((file_id = H5VL_register(H5I_FILE, vol_obj_file, vol_obj->connector, app_ref)) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize file handle")
-        file->id_exists = TRUE;
     } /* end if */
     else {
         /* Increment ref count on existing ID */
@@ -3693,44 +3702,6 @@ H5F__get_file_id(H5F_t *file, hbool_t app_ref)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F__get_file_id() */
-
-
-/*-------------------------------------------------------------------------
- * Function:    H5F_get_file_id
- *
- * Purpose:     The private version of H5Iget_file_id(), obtains the file
- *              ID given an object ID.
- *
- * Return:      Success:    The file ID associated with the object
- *              Failure:    H5I_INVALID_HID
- *
- *-------------------------------------------------------------------------
- */
-hid_t
-H5F_get_file_id(hid_t obj_id, H5I_type_t type, hbool_t app_ref)
-{
-    H5VL_object_t  *vol_obj;                    /* File info */
-    hid_t           file_id = H5I_INVALID_HID;  /* File ID for object */
-    hid_t           ret_value = H5I_INVALID_HID; /* Return value */
-
-    FUNC_ENTER_NOAPI(H5I_INVALID_HID)
-
-    /* Get the object pointer */
-    if(NULL == (vol_obj = H5VL_vol_object(obj_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid identifier")
-
-    /* Get the file through the VOL */
-    if(H5VL_file_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_FILE_GET_FILE_ID, (int)type, (int)app_ref, &file_id) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, H5I_INVALID_HID, "unable to get file ID")
-    if(H5I_INVALID_HID == file_id)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, H5I_INVALID_HID, "unable to get the file ID through the VOL")
-
-    /* Set return value */
-    ret_value = file_id;
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_get_file_id() */
 
 
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index 7d9a090..6e2c994 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -412,7 +412,6 @@ H5_DLL herr_t H5F__start_swmr_write(H5F_t *f);
 H5_DLL herr_t H5F__close(H5F_t *f);
 H5_DLL herr_t H5F__set_libver_bounds(H5F_t *f, H5F_libver_t low, H5F_libver_t high);
 H5_DLL H5F_t *H5F__get_file(void *obj, H5I_type_t type);
-H5_DLL hid_t H5F__get_file_id(H5F_t *file, hbool_t app_ref);
 H5_DLL herr_t H5F__get_cont_info(const H5F_t *f, H5VL_file_cont_info_t *info);
 
 /* File mount related routines */
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index e1a8a2f..cfb796c 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -732,7 +732,7 @@ typedef enum H5F_prefix_open_t {
 /* Private functions */
 H5_DLL H5F_t *H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id);
 H5_DLL herr_t H5F_try_close(H5F_t *f, hbool_t *was_closed/*out*/);
-H5_DLL hid_t H5F_get_file_id(hid_t obj_id, H5I_type_t id_type, hbool_t app_ref);
+H5_DLL hid_t H5F_get_file_id(H5VL_object_t *vol_obj, H5I_type_t obj_type, hbool_t app_ref);
 
 /* Functions that retrieve values from the file struct */
 H5_DLL H5F_libver_t H5F_get_low_bound(const H5F_t *f);
diff --git a/src/H5I.c b/src/H5I.c
index 76faab1..c3c2d46 100644
--- a/src/H5I.c
+++ b/src/H5I.c
@@ -2270,7 +2270,14 @@ H5Iget_file_id(hid_t obj_id)
 
     /* Call internal function */
     if (H5I_FILE == type || H5I_DATATYPE == type || H5I_GROUP == type || H5I_DATASET == type || H5I_ATTR == type) {
-        if ((ret_value = H5F_get_file_id(obj_id, type, TRUE)) < 0)
+        H5VL_object_t *vol_obj = NULL; /* Object token of obj_id */
+
+        /* Get the VOL object */
+        if(NULL == (vol_obj = H5VL_vol_object(obj_id)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
+
+        /* Get the file ID */
+        if ((ret_value = H5F_get_file_id(vol_obj, type, TRUE)) < 0)
             HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, H5I_INVALID_HID, "can't retrieve file ID")
     } /* end if */
     else
diff --git a/src/H5O.c b/src/H5O.c
index b79914c..3938413 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -278,7 +278,7 @@ H5Oopen_by_addr(hid_t loc_id, haddr_t addr)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
 
     /* Get the file for the object */
-    if((file_id = H5F_get_file_id(loc_id, vol_obj_type, FALSE)) < 0)
+    if((file_id = H5F_get_file_id(vol_obj, vol_obj_type, FALSE)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a file or file object")
 
     /* Retrieve VOL object */
@@ -290,11 +290,11 @@ H5Oopen_by_addr(hid_t loc_id, haddr_t addr)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid VOL object")
 
     /* This is a native specific routine that requires serialization of the token */
-    p = obj_token;
+    p = (uint8_t *)&obj_token;
     H5F_addr_encode(f, &p, addr);
 
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = vol_obj_type;
 
     /* Open the object */
diff --git a/src/H5Ocopy_ref.c b/src/H5Ocopy_ref.c
index d8efeb5..b835f8e 100644
--- a/src/H5Ocopy_ref.c
+++ b/src/H5Ocopy_ref.c
@@ -24,7 +24,6 @@
 /****************/
 
 #include "H5Omodule.h"          /* This source code file is part of the H5O module */
-#define H5F_FRIEND              /* Suppress error about including H5Fpkg   */
 #define H5R_FRIEND              /* Suppress error about including H5Rpkg   */
 
 
@@ -32,7 +31,7 @@
 /* Headers */
 /***********/
 #include "H5private.h"          /* Generic Functions                        */
-#include "H5Fpkg.h"             /* File                                     */
+#include "H5Fprivate.h"         /* File                                     */
 #include "H5Iprivate.h"         /* IDs                                      */
 #include "H5Lprivate.h"         /* Links                                    */
 #include "H5MMprivate.h"        /* Memory management                        */
@@ -186,7 +185,7 @@ H5O__copy_expand_ref_object1(H5O_loc_t *src_oloc, const void *buf_src,
         /* Set up for the object copy for the reference */
         if(H5R__decode_token_obj_compat(src_buf, &buf_size, &tmp_token, token_size) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTDECODE, FAIL, "unable to decode src object address")
-        p = tmp_token;
+        p = (uint8_t *)&tmp_token;
         H5F_addr_decode(src_oloc->file, (const uint8_t **)&p, &src_oloc->addr);
         if(!H5F_addr_defined(src_oloc->addr) || src_oloc->addr == 0)
             HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "undefined reference pointer")
@@ -197,7 +196,7 @@ H5O__copy_expand_ref_object1(H5O_loc_t *src_oloc, const void *buf_src,
             HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to copy object")
 
         /* Set the object reference info for the destination file */
-        p = tmp_token;
+        p = (uint8_t *)&tmp_token;
         H5F_addr_encode(dst_oloc->file, &p, dst_oloc->addr);
         if(H5R__encode_token_obj_compat((const H5VL_token_t *)&tmp_token, token_size, dst_buf, &buf_size) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTDECODE, FAIL, "unable to encode dst object address")
@@ -359,7 +358,7 @@ H5O__copy_expand_ref_object2(H5O_loc_t *src_oloc, hid_t tid_src, H5T_t *dt_src,
         HGOTO_ERROR(H5E_OHDR, H5E_CANTCONVERT, FAIL, "datatype conversion failed")
 
     /* Retrieve loc ID */
-    if((dst_loc_id = H5F__get_file_id(dst_oloc->file, FALSE)) < 0)
+    if((dst_loc_id = H5F_get_id(dst_oloc->file)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
 
     /* Making equivalent references in the destination file */
@@ -372,7 +371,7 @@ H5O__copy_expand_ref_object2(H5O_loc_t *src_oloc, hid_t tid_src, H5T_t *dt_src,
         /* Get src object address */
         if(H5R__get_obj_token(ref, &tmp_token, &token_size) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to get object token")
-        p = tmp_token;
+        p = (uint8_t *)&tmp_token;
         H5F_addr_decode(src_oloc->file, (const uint8_t **)&p, &src_oloc->addr);
 
         /* Attempt to copy object from source to destination file */
@@ -380,7 +379,7 @@ H5O__copy_expand_ref_object2(H5O_loc_t *src_oloc, hid_t tid_src, H5T_t *dt_src,
             HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to copy object")
 
         /* Set dst object address */
-        p = tmp_token;
+        p = (uint8_t *)&tmp_token;
         H5F_addr_encode(dst_oloc->file, &p, dst_oloc->addr);
         if(H5R__set_obj_token(ref, (const H5VL_token_t *)&tmp_token, token_size) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "unable to set object token")
diff --git a/src/H5R.c b/src/H5R.c
index 162bd8c..2c4c713 100644
--- a/src/H5R.c
+++ b/src/H5R.c
@@ -112,7 +112,7 @@ H5Rcreate_object(hid_t loc_id, const char *name, hid_t oapl_id, H5R_ref_t *ref_p
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Get the file for the object */
-    if((file_id = H5F_get_file_id(loc_id, obj_type, FALSE)) < 0)
+    if((file_id = H5F_get_file_id(vol_obj, obj_type, FALSE)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
 
     /* Retrieve VOL file object */
@@ -130,7 +130,7 @@ H5Rcreate_object(hid_t loc_id, const char *name, hid_t oapl_id, H5R_ref_t *ref_p
     loc_params.obj_type = obj_type;
 
     /* Get the object token */
-    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_token) < 0)
+    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to retrieve object token")
 
     /* Create the reference (do not pass filename, since file_id is attached) */
@@ -205,7 +205,7 @@ H5Rcreate_region(hid_t loc_id, const char *name, hid_t space_id,
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Get the file for the object */
-    if((file_id = H5F_get_file_id(loc_id, obj_type, FALSE)) < 0)
+    if((file_id = H5F_get_file_id(vol_obj, obj_type, FALSE)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
 
     /* Retrieve VOL file object */
@@ -223,7 +223,7 @@ H5Rcreate_region(hid_t loc_id, const char *name, hid_t space_id,
     loc_params.obj_type = obj_type;
 
     /* Get the object token */
-    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_token) < 0)
+    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to retrieve object token")
 
     /* Create the reference (do not pass filename, since file_id is attached) */
@@ -294,7 +294,7 @@ H5Rcreate_attr(hid_t loc_id, const char *name, const char *attr_name,
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Get the file for the object */
-    if((file_id = H5F_get_file_id(loc_id, obj_type, FALSE)) < 0)
+    if((file_id = H5F_get_file_id(vol_obj, obj_type, FALSE)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
 
     /* Retrieve VOL file object */
@@ -312,7 +312,7 @@ H5Rcreate_attr(hid_t loc_id, const char *name, const char *attr_name,
     loc_params.obj_type = obj_type;
 
     /* Get the object token */
-    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_token) < 0)
+    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to retrieve object token")
 
     /* Create the reference (do not pass filename, since file_id is attached) */
@@ -511,7 +511,7 @@ H5Ropen_object(const H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t oapl_id)
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = H5I_get_type(loc_id);
 
     /* Open object by token */
@@ -583,7 +583,7 @@ H5Ropen_region(const H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t oapl_id)
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = H5I_get_type(loc_id);
 
     /* Open object by token */
@@ -675,7 +675,7 @@ H5Ropen_attr(const H5R_ref_t *ref_ptr, hid_t rapl_id, hid_t aapl_id)
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = H5I_get_type(loc_id);
 
     /* Open object by token */
@@ -765,7 +765,7 @@ H5Rget_obj_type3(const H5R_ref_t *ref_ptr, hid_t rapl_id, H5O_type_t *obj_type)
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = H5I_get_type(loc_id);
 
     /* Retrieve object's type */
@@ -873,7 +873,7 @@ H5Rget_obj_name(const H5R_ref_t *ref_ptr, hid_t rapl_id, char *buf, size_t size)
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = H5I_get_type(loc_id);
 
     /* Retrieve object's name */
diff --git a/src/H5Rdeprec.c b/src/H5Rdeprec.c
index f0dc503..ad3c219 100644
--- a/src/H5Rdeprec.c
+++ b/src/H5Rdeprec.c
@@ -123,12 +123,12 @@ H5Rget_obj_type1(hid_t id, H5R_type_t ref_type, const void *ref)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5G_UNKNOWN, "invalid location identifier")
 
     /* Get object token */
-    if(H5R__decode_token_compat(id, vol_obj_type, ref_type, buf, &obj_token) < 0)
+    if(H5R__decode_token_compat(vol_obj, vol_obj_type, ref_type, buf, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, H5G_UNKNOWN, "unable to get object token")
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = vol_obj_type;
 
     /* Retrieve object's type */
@@ -183,12 +183,12 @@ H5Rdereference1(hid_t obj_id, H5R_type_t ref_type, const void *ref)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
 
     /* Get object token */
-    if(H5R__decode_token_compat(obj_id, vol_obj_type, ref_type, buf, &obj_token) < 0)
+    if(H5R__decode_token_compat(vol_obj, vol_obj_type, ref_type, buf, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, H5I_INVALID_HID, "unable to get object token")
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = vol_obj_type;
 
     /* Dereference */
@@ -262,11 +262,11 @@ H5Rcreate(void *ref, hid_t loc_id, const char *name, H5R_type_t ref_type,
     loc_params.obj_type = vol_obj_type;
 
     /* Get the object token */
-    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, obj_token) < 0)
+    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_LOOKUP, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, FAIL, "unable to retrieve object token")
 
     /* Get the file for the object */
-    if((file_id = H5F_get_file_id(loc_id, vol_obj_type, FALSE)) < 0)
+    if((file_id = H5F_get_file_id(vol_obj, vol_obj_type, FALSE)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
 
     /* Retrieve VOL object */
@@ -352,12 +352,12 @@ H5Rget_obj_type2(hid_t id, H5R_type_t ref_type, const void *ref,
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Get object token */
-    if(H5R__decode_token_compat(id, vol_obj_type, ref_type, buf, &obj_token) < 0)
+    if(H5R__decode_token_compat(vol_obj, vol_obj_type, ref_type, buf, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, FAIL, "unable to get object token")
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = vol_obj_type;
 
     /* Retrieve object's type */
@@ -416,12 +416,12 @@ H5Rdereference2(hid_t obj_id, hid_t oapl_id, H5R_type_t ref_type,
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
 
     /* Get object token */
-    if(H5R__decode_token_compat(obj_id, vol_obj_type, ref_type, buf, &obj_token) < 0)
+    if(H5R__decode_token_compat(vol_obj, vol_obj_type, ref_type, buf, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, H5I_INVALID_HID, "unable to get object token")
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = vol_obj_type;
 
     /* Open object by token */
@@ -480,7 +480,7 @@ H5Rget_region(hid_t id, H5R_type_t ref_type, const void *ref)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
 
     /* Get the file for the object */
-    if((file_id = H5F_get_file_id(id, vol_obj_type, FALSE)) < 0)
+    if((file_id = H5F_get_file_id(vol_obj, vol_obj_type, FALSE)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "not a file or file object")
 
     /* Retrieve VOL object */
@@ -549,12 +549,12 @@ H5Rget_name(hid_t id, H5R_type_t ref_type, const void *ref, char *name,
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "invalid location identifier")
 
     /* Get object token */
-    if(H5R__decode_token_compat(id, vol_obj_type, ref_type, buf, &obj_token) < 0)
+    if(H5R__decode_token_compat(vol_obj, vol_obj_type, ref_type, buf, &obj_token) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, (-1), "unable to get object token")
 
     /* Set location parameters */
     loc_params.type = H5VL_OBJECT_BY_TOKEN;
-    loc_params.loc_data.loc_by_token.token = obj_token;
+    loc_params.loc_data.loc_by_token.token = &obj_token;
     loc_params.obj_type = vol_obj_type;
 
     /* Retrieve object's name */
diff --git a/src/H5Rint.c b/src/H5Rint.c
index 504ae06..9879865 100644
--- a/src/H5Rint.c
+++ b/src/H5Rint.c
@@ -258,7 +258,7 @@ H5R__create_object(const H5VL_token_t *obj_token, size_t token_size,
     HDassert(ref);
 
     /* Create new reference */
-    H5MM_memcpy(ref->ref.obj.token, obj_token, token_size);
+    H5MM_memcpy(&ref->ref.obj.token, obj_token, token_size);
     ref->ref.obj.filename = NULL;
     ref->loc_id = H5I_INVALID_HID;
     ref->type = (uint8_t)H5R_OBJECT2;
@@ -300,7 +300,7 @@ H5R__create_region(const H5VL_token_t *obj_token, size_t token_size,
     HDassert(ref);
 
     /* Create new reference */
-    H5MM_memcpy(ref->ref.obj.token, obj_token, token_size);
+    H5MM_memcpy(&ref->ref.obj.token, obj_token, token_size);
     ref->ref.obj.filename = NULL;
     if(NULL == (ref->ref.reg.space = H5S_copy(space, FALSE, TRUE)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOPY, FAIL, "unable to copy dataspace")
@@ -355,7 +355,7 @@ H5R__create_attr(const H5VL_token_t *obj_token, size_t token_size,
         HGOTO_ERROR(H5E_REFERENCE, H5E_ARGS, FAIL, "attribute name too long (%d > %d)", (int)HDstrlen(attr_name), H5R_MAX_STRING_LEN)
 
     /* Create new reference */
-    H5MM_memcpy(ref->ref.obj.token, obj_token, token_size);
+    H5MM_memcpy(&ref->ref.obj.token, obj_token, token_size);
     ref->ref.obj.filename = NULL;
     if(NULL == (ref->ref.attr.name = HDstrdup(attr_name)))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOPY, FAIL, "Cannot copy attribute name")
@@ -413,6 +413,7 @@ H5R__destroy(H5R_ref_priv_t *ref)
             break;
         case H5R_OBJECT1:
         case H5R_DATASET_REGION1:
+            break;
         case H5R_BADTYPE:
         case H5R_MAXTYPE:
             HDassert("invalid reference type" && 0);
@@ -423,7 +424,7 @@ H5R__destroy(H5R_ref_priv_t *ref)
     } /* end switch */
 
     /* Decrement refcount of attached loc_id */
-    if((ref->loc_id != H5I_INVALID_HID) && (H5I_dec_ref(ref->loc_id) < 0))
+    if(ref->type && (ref->loc_id != H5I_INVALID_HID) && (H5I_dec_ref(ref->loc_id) < 0))
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDEC, FAIL, "decrementing location ID failed")
 
 done:
@@ -601,7 +602,7 @@ H5R__equal(const H5R_ref_priv_t *ref1, const H5R_ref_priv_t *ref2)
     /* Compare object addresses */
     if(ref1->token_size != ref2->token_size)
         HGOTO_DONE(FALSE);
-    if(0 != HDmemcmp(ref1->ref.obj.token, ref2->ref.obj.token, ref1->token_size))
+    if(0 != HDmemcmp(&ref1->ref.obj.token, &ref2->ref.obj.token, ref1->token_size))
         HGOTO_DONE(FALSE);
 
     /* Compare filenames */
@@ -658,7 +659,7 @@ H5R__copy(const H5R_ref_priv_t *src_ref, H5R_ref_priv_t *dst_ref)
 
     HDassert((src_ref != NULL) && (dst_ref != NULL));
 
-    H5MM_memcpy(dst_ref->ref.obj.token, src_ref->ref.obj.token, src_ref->token_size);
+    H5MM_memcpy(&dst_ref->ref.obj.token, &src_ref->ref.obj.token, src_ref->token_size);
     dst_ref->encode_size = src_ref->encode_size;
     dst_ref->type = src_ref->type;
     dst_ref->token_size = src_ref->token_size;
@@ -728,7 +729,7 @@ H5R__get_obj_token(const H5R_ref_priv_t *ref, H5VL_token_t *obj_token,
     if(obj_token) {
         if(0 == ref->token_size)
             HGOTO_ERROR(H5E_REFERENCE, H5E_CANTCOPY, FAIL, "NULL token size")
-        H5MM_memcpy(obj_token, ref->ref.obj.token, ref->token_size);
+        H5MM_memcpy(obj_token, &ref->ref.obj.token, ref->token_size);
     }
     if(token_size)
         *token_size = ref->token_size;
@@ -760,7 +761,7 @@ H5R__set_obj_token(H5R_ref_priv_t *ref, const H5VL_token_t *obj_token,
     HDassert(token_size);
     HDassert(token_size <= H5VL_MAX_TOKEN_SIZE);
 
-    H5MM_memcpy(ref->ref.obj.token, obj_token, ref->token_size);
+    H5MM_memcpy(&ref->ref.obj.token, obj_token, ref->token_size);
     ref->token_size = token_size;
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1479,18 +1480,18 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5R__decode_token_compat(hid_t id, H5I_type_t type, H5R_type_t ref_type,
+H5R__decode_token_compat(H5VL_object_t *vol_obj, H5I_type_t type, H5R_type_t ref_type,
     const unsigned char *buf, H5VL_token_t *obj_token)
 {
     hid_t file_id = H5I_INVALID_HID;    /* File ID for region reference */
-    void *vol_obj_file = NULL;
+    H5VL_object_t *vol_obj_file = NULL;
     H5VL_file_cont_info_t cont_info = {H5VL_CONTAINER_INFO_VERSION, 0, 0, 0};
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_PACKAGE
 
     /* Get the file for the object */
-    if((file_id = H5F_get_file_id(id, type, FALSE)) < 0)
+    if((file_id = H5F_get_file_id(vol_obj, type, FALSE)) < 0)
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
 
     /* Retrieve VOL object */
@@ -1701,13 +1702,13 @@ H5R__decode_token_region_compat(H5F_t *f, const unsigned char *buf,
 
     /* Get object address */
     p = (const uint8_t *)data;
-    H5MM_memcpy(token, p, token_size);
+    H5MM_memcpy(&token, p, token_size);
     p += token_size;
 
     if(space_ptr) {
         H5O_loc_t oloc; /* Object location */
         H5S_t *space = NULL;
-        const uint8_t *q = token;
+        const uint8_t *q = (const uint8_t *)&token;
 
         /* Initialize the object location */
         H5O_loc_reset(&oloc);
@@ -1725,7 +1726,7 @@ H5R__decode_token_region_compat(H5F_t *f, const unsigned char *buf,
         *space_ptr = space;
     }
     if(obj_token)
-        H5MM_memcpy(obj_token, token, token_size);
+        H5MM_memcpy(obj_token, &token, token_size);
 
 done:
     H5MM_free(data);
diff --git a/src/H5Rpkg.h b/src/H5Rpkg.h
index 19f3115..7471487 100644
--- a/src/H5Rpkg.h
+++ b/src/H5Rpkg.h
@@ -118,7 +118,7 @@ H5_DLL herr_t   H5R__encode_heap(H5F_t *f, unsigned char *buf, size_t *nalloc, c
 H5_DLL herr_t   H5R__decode_heap(H5F_t *f, const unsigned char *buf, size_t *nbytes, unsigned char **data_ptr, size_t *data_size);
 H5_DLL herr_t   H5R__free_heap(H5F_t *f, const unsigned char *buf, size_t nbytes);
 
-H5_DLL herr_t   H5R__decode_token_compat(hid_t id, H5I_type_t type, H5R_type_t ref_type, const unsigned char *buf, H5VL_token_t *obj_token);
+H5_DLL herr_t   H5R__decode_token_compat(H5VL_object_t *vol_obj, H5I_type_t type, H5R_type_t ref_type, const unsigned char *buf, H5VL_token_t *obj_token);
 
 H5_DLL herr_t   H5R__encode_token_obj_compat(const H5VL_token_t *obj_token, size_t token_size, unsigned char *buf, size_t *nalloc);
 H5_DLL herr_t   H5R__decode_token_obj_compat(const unsigned char *buf, size_t *nbytes, H5VL_token_t *obj_token, size_t token_size);
diff --git a/src/H5Rpublic.h b/src/H5Rpublic.h
index 585cb85..a13d54b 100644
--- a/src/H5Rpublic.h
+++ b/src/H5Rpublic.h
@@ -70,14 +70,18 @@ typedef haddr_t hobj_ref_t;
  * machine (8 bytes currently) plus an int.
  * Note! This type can only be used with the "native" HDF5 VOL connector.
  */
-typedef unsigned char hdset_reg_ref_t[H5R_DSET_REG_REF_BUF_SIZE];
+typedef struct {
+    char __data[H5R_DSET_REG_REF_BUF_SIZE];
+} hdset_reg_ref_t;
 
 /**
  * Opaque reference type. The same reference type is used for object,
  * dataset region and attribute references. This is the type that
  * should always be used with the current reference API.
  */
-typedef unsigned char H5R_ref_t[H5R_REF_BUF_SIZE];
+typedef struct {
+    char __data[H5R_REF_BUF_SIZE];
+} H5R_ref_t;
 
 /********************/
 /* Public Variables */
diff --git a/src/H5Tconv.c b/src/H5Tconv.c
index 6aea00e..4cc5f3c 100644
--- a/src/H5Tconv.c
+++ b/src/H5Tconv.c
@@ -3609,39 +3609,52 @@ H5T__conv_ref(hid_t src_id, hid_t dst_id, H5T_cdata_t *cdata, size_t nelmts,
                 for(elmtno = 0; elmtno < safe; elmtno++) {
                     size_t buf_size;
                     hbool_t dst_copy = FALSE;
+                    hbool_t is_nil; /* Whether sequence is "nil" */
 
-                    /* Get size of references */
-                    if(0 == (buf_size = src->shared->u.atomic.u.r.cls->getsize(
-                        src->shared->u.atomic.u.r.file, s, src->shared->size,
-                        dst->shared->u.atomic.u.r.file, &dst_copy)))
-                        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "incorrect size")
-
-                    /* Check if conversion buffer is large enough, resize if necessary. */
-                    if(conv_buf_size < buf_size) {
-                        conv_buf_size = buf_size;
-                        if(NULL == (conv_buf = H5FL_BLK_REALLOC(ref_seq, conv_buf, conv_buf_size)))
-                            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for type conversion")
-                        HDmemset(conv_buf, 0, conv_buf_size);
-                    } /* end if */
+                    /* Check for "nil" source sequence */
+                    if((*(src->shared->u.atomic.u.r.cls->isnull))(src->shared->u.atomic.u.r.file, s, &is_nil) < 0)
+                        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "can't check if reference data is 'nil'")
 
-                    if(dst_copy && (src->shared->u.atomic.u.r.loc == H5T_LOC_DISK)) {
-                        H5MM_memcpy(conv_buf, s, buf_size);
-                    } else {
-                        /* Read reference */
-                        if(src->shared->u.atomic.u.r.cls->read(
+                    if(is_nil) {
+
+                        /* Write "nil" sequence to destination location */
+                        if((*(dst->shared->u.atomic.u.r.cls->setnull))(dst->shared->u.atomic.u.r.file, d, b) < 0)
+                            HGOTO_ERROR(H5E_DATATYPE, H5E_WRITEERROR, FAIL, "can't set reference data to 'nil'")
+                    } /* end else-if */
+                    else {
+                        /* Get size of references */
+                        if(0 == (buf_size = src->shared->u.atomic.u.r.cls->getsize(
                             src->shared->u.atomic.u.r.file, s, src->shared->size,
-                            dst->shared->u.atomic.u.r.file, conv_buf, buf_size) < 0)
-                            HGOTO_ERROR(H5E_DATATYPE, H5E_READERROR, FAIL, "can't read reference data")
-                    }
+                            dst->shared->u.atomic.u.r.file, &dst_copy)))
+                            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "incorrect size")
+
+                        /* Check if conversion buffer is large enough, resize if necessary. */
+                        if(conv_buf_size < buf_size) {
+                            conv_buf_size = buf_size;
+                            if(NULL == (conv_buf = H5FL_BLK_REALLOC(ref_seq, conv_buf, conv_buf_size)))
+                                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed for type conversion")
+                            HDmemset(conv_buf, 0, conv_buf_size);
+                        } /* end if */
 
-                    if(dst_copy && (dst->shared->u.atomic.u.r.loc == H5T_LOC_DISK)) {
-                        H5MM_memcpy(d, conv_buf, buf_size);
-                    } else {
-                        /* Write reference to destination location */
-                        if(dst->shared->u.atomic.u.r.cls->write(
-                            src->shared->u.atomic.u.r.file, conv_buf, buf_size, src->shared->u.atomic.u.r.rtype,
-                            dst->shared->u.atomic.u.r.file, d, dst->shared->size, b) < 0)
-                            HGOTO_ERROR(H5E_DATATYPE, H5E_WRITEERROR, FAIL, "can't write reference data")
+                        if(dst_copy && (src->shared->u.atomic.u.r.loc == H5T_LOC_DISK)) {
+                            H5MM_memcpy(conv_buf, s, buf_size);
+                        } else {
+                            /* Read reference */
+                            if(src->shared->u.atomic.u.r.cls->read(
+                                src->shared->u.atomic.u.r.file, s, src->shared->size,
+                                dst->shared->u.atomic.u.r.file, conv_buf, buf_size) < 0)
+                                HGOTO_ERROR(H5E_DATATYPE, H5E_READERROR, FAIL, "can't read reference data")
+                        }
+
+                        if(dst_copy && (dst->shared->u.atomic.u.r.loc == H5T_LOC_DISK)) {
+                            H5MM_memcpy(d, conv_buf, buf_size);
+                        } else {
+                            /* Write reference to destination location */
+                            if(dst->shared->u.atomic.u.r.cls->write(
+                                src->shared->u.atomic.u.r.file, conv_buf, buf_size, src->shared->u.atomic.u.r.rtype,
+                                dst->shared->u.atomic.u.r.file, d, dst->shared->size, b) < 0)
+                                HGOTO_ERROR(H5E_DATATYPE, H5E_WRITEERROR, FAIL, "can't write reference data")
+                        }
                     }
 
                     /* Advance pointers */
diff --git a/src/H5Tpkg.h b/src/H5Tpkg.h
index 1dbc229..39bff15 100644
--- a/src/H5Tpkg.h
+++ b/src/H5Tpkg.h
@@ -182,11 +182,15 @@ struct H5T_path_t {
 };
 
 /* Reference function pointers */
+typedef herr_t (*H5T_ref_isnullfunc_t)(const H5VL_object_t *file, const void *src_buf, hbool_t *isnull);
+typedef herr_t (*H5T_ref_setnullfunc_t)(H5VL_object_t *file, void *dst_buf, void *bg_buf);
 typedef size_t (*H5T_ref_getsizefunc_t)(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
 typedef herr_t (*H5T_ref_readfunc_t)(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);
 typedef herr_t (*H5T_ref_writefunc_t)(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5R_type_t src_type, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size, void *bg_buf);
 
 typedef struct H5T_ref_class_t {
+    H5T_ref_isnullfunc_t    isnull;     /* check if reference value is NIL */
+    H5T_ref_setnullfunc_t   setnull;    /* set a reference value to NIL */
     H5T_ref_getsizefunc_t   getsize;    /* get reference size (bytes)   */
     H5T_ref_readfunc_t      read;       /* read reference into buffer   */
     H5T_ref_writefunc_t     write;      /* write reference from buffer  */
diff --git a/src/H5Tref.c b/src/H5Tref.c
index 23548b3..6f21363 100644
--- a/src/H5Tref.c
+++ b/src/H5Tref.c
@@ -54,18 +54,24 @@ struct H5Tref_dsetreg {
 /* Local Prototypes */
 /********************/
 
+static herr_t H5T__ref_mem_isnull(const H5VL_object_t *src_file, const void *src_buf, hbool_t *isnull);
+static herr_t H5T__ref_mem_setnull(H5VL_object_t *dst_file, void *dst_buf, void *bg_buf);
 static size_t H5T__ref_mem_getsize(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
 static herr_t H5T__ref_mem_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);
 static herr_t H5T__ref_mem_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5R_type_t src_type, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size, void *bg_buf);
 
+static herr_t H5T__ref_disk_isnull(const H5VL_object_t *src_file, const void *src_buf, hbool_t *isnull);
+static herr_t H5T__ref_disk_setnull(H5VL_object_t *dst_file, void *dst_buf, void *bg_buf);
 static size_t H5T__ref_disk_getsize(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
 static herr_t H5T__ref_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);
 static herr_t H5T__ref_disk_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5R_type_t src_type, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size, void *bg_buf);
 
 /* For compatibility */
+static herr_t H5T__ref_obj_disk_isnull(const H5VL_object_t *src_file, const void *src_buf, hbool_t *isnull);
 static size_t H5T__ref_obj_disk_getsize(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
 static herr_t H5T__ref_obj_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);
 
+static herr_t H5T__ref_dsetreg_disk_isnull(const H5VL_object_t *src_file, const void *src_buf, hbool_t *isnull);
 static size_t H5T__ref_dsetreg_disk_getsize(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, hbool_t *dst_copy);
 static herr_t H5T__ref_dsetreg_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size, H5VL_object_t *dst_file, void *dst_buf, size_t dst_size);
 
@@ -75,24 +81,32 @@ static herr_t H5T__ref_dsetreg_disk_read(H5VL_object_t *src_file, const void *sr
 
 /* Class for reference in memory */
 static const H5T_ref_class_t H5T_ref_mem_g = {
+    H5T__ref_mem_isnull,            /* 'isnull' */
+    H5T__ref_mem_setnull,           /* 'setnull' */
     H5T__ref_mem_getsize,           /* 'getsize' */
     H5T__ref_mem_read,              /* 'read' */
     H5T__ref_mem_write              /* 'write' */
 };
 
 static const H5T_ref_class_t H5T_ref_disk_g = {
+    H5T__ref_disk_isnull,           /* 'isnull' */
+    H5T__ref_disk_setnull,          /* 'setnull' */
     H5T__ref_disk_getsize,          /* 'getsize' */
     H5T__ref_disk_read,             /* 'read' */
     H5T__ref_disk_write             /* 'write' */
 };
 
 static const H5T_ref_class_t H5T_ref_obj_disk_g = {
+    H5T__ref_obj_disk_isnull,       /* 'isnull' */
+    NULL,                           /* 'setnull' */
     H5T__ref_obj_disk_getsize,      /* 'getsize' */
     H5T__ref_obj_disk_read,         /* 'read' */
     NULL                            /* 'write' */
 };
 
 static const H5T_ref_class_t H5T_ref_dsetreg_disk_g = {
+    H5T__ref_dsetreg_disk_isnull,   /* 'isnull' */
+    NULL,                           /* 'setnull' */
     H5T__ref_dsetreg_disk_getsize,  /* 'getsize' */
     H5T__ref_dsetreg_disk_read,     /* 'read' */
     NULL                            /* 'write' */
@@ -268,6 +282,57 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5T__ref_mem_isnull
+ *
+ * Purpose: Check if it's a NULL / uninitialized reference.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5T__ref_mem_isnull(const H5VL_object_t H5_ATTR_UNUSED *src_file,
+    const void *src_buf, hbool_t *isnull)
+{
+    const unsigned char zeros[H5T_REF_MEM_SIZE] = { 0 };
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check parameters */
+    HDassert(src_buf);
+    HDassert(isnull);
+
+    *isnull = (0 == HDmemcmp(src_buf, zeros, H5T_REF_MEM_SIZE)) ? TRUE : FALSE;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* end H5T__ref_mem_isnull() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5T__ref_mem_setnull
+ *
+ * Purpose: Set a reference as NULL / uninitialized.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5T__ref_mem_setnull(H5VL_object_t H5_ATTR_UNUSED *dst_file, void *dst_buf,
+    H5_ATTR_UNUSED void *bg_buf)
+{
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    HDmemset(dst_buf, 0, H5T_REF_MEM_SIZE);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* end H5T__ref_mem_setnull() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5T__ref_mem_getsize
  *
  * Purpose:	Retrieves the size of a memory based reference.
@@ -508,7 +573,7 @@ H5T__ref_mem_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size
     /* If no filename set, this is not an external reference */
     if(NULL == H5R_REF_FILENAME(dst_ref)) {
         /* TODO temporary hack to retrieve file object */
-        if((file_id = H5F__get_file_id(src_f, FALSE)) < 0)
+        if((file_id = H5F_get_file_id(src_file, H5I_FILE, FALSE)) < 0)
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
 
         /* Attach loc ID to reference and hold reference to it */
@@ -524,6 +589,96 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5T__ref_disk_isnull
+ *
+ * Purpose: Check if it's a NULL / uninitialized reference.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5T__ref_disk_isnull(const H5VL_object_t *src_file, const void *src_buf,
+    hbool_t *isnull)
+{
+    const uint8_t *p = (const uint8_t *)src_buf;
+    H5R_type_t ref_type;
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Check parameters */
+    HDassert(src_file);
+    HDassert(src_buf);
+    HDassert(isnull);
+
+    /* Try to check encoded reference type */
+    ref_type = (H5R_type_t)*p++;
+    if(ref_type) {
+        /* This is a valid reference */
+        *isnull = FALSE;
+    } else {
+        /* Skip the size / header */
+        p = (const uint8_t *)src_buf + H5R_ENCODE_HEADER_SIZE + H5_SIZEOF_UINT32_T;
+
+        /* Check if blob ID is "nil" */
+        if(H5VL_blob_specific(src_file, (void *)p, H5VL_BLOB_ISNULL, isnull) < 0)
+            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "unable to check if a blob ID is 'nil'")
+    }
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* end H5T__ref_disk_isnull() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5T__ref_disk_setnull
+ *
+ * Purpose: Set a reference as NULL / uninitialized.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5T__ref_disk_setnull(H5VL_object_t *dst_file, void *dst_buf, void *bg_buf)
+{
+    uint8_t *q = (uint8_t *)dst_buf;
+    uint8_t *p_bg = (uint8_t *)bg_buf;
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    HDassert(dst_file);
+    HDassert(dst_buf);
+
+    /* TODO Should get rid of bg stuff */
+    if(p_bg) {
+        /* Skip the size / header */
+        p_bg += (H5_SIZEOF_UINT32_T + H5R_ENCODE_HEADER_SIZE);
+
+        /* Remove blob for old data */
+        if(H5VL_blob_specific(dst_file, (void *)p_bg, H5VL_BLOB_DELETE) < 0)
+            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTREMOVE, FAIL, "unable to delete blob")
+    } /* end if */
+
+    /* Copy header manually so that it does not get encoded into the blob */
+    HDmemset(q, 0, H5R_ENCODE_HEADER_SIZE);
+    q += H5R_ENCODE_HEADER_SIZE;
+
+    /* Set the size */
+    UINT32ENCODE(q, 0);
+
+    /* Set blob ID to "nil" */
+    if(H5VL_blob_specific(dst_file, q, H5VL_BLOB_SETNULL) < 0)
+        HGOTO_ERROR(H5E_DATATYPE, H5E_CANTSET, FAIL, "unable to set a blob ID to 'nil'")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* end H5T__ref_disk_setnull() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5T__ref_disk_getsize
  *
  * Purpose:	Retrieves the length of a disk based reference.
@@ -602,7 +757,7 @@ H5T__ref_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_size
     q += H5R_ENCODE_HEADER_SIZE;
     blob_size -= H5R_ENCODE_HEADER_SIZE;
 
-    /* Skip the length of the sequence */
+    /* Skip the size */
     p += H5_SIZEOF_UINT32_T;
     HDassert(src_size > (H5R_ENCODE_HEADER_SIZE + H5_SIZEOF_UINT32_T));
 
@@ -646,10 +801,10 @@ H5T__ref_disk_write(H5VL_object_t H5_ATTR_UNUSED *src_file, const void *src_buf,
     if(p_bg) {
         size_t p_buf_size_left = dst_size;
 
-        /* Skip the length of the reference */
-        p_bg += H5_SIZEOF_UINT32_T;
-        HDassert(p_buf_size_left > H5_SIZEOF_UINT32_T);
-        p_buf_size_left -= H5_SIZEOF_UINT32_T;
+        /* Skip the size / header */
+        p_bg += (H5_SIZEOF_UINT32_T + H5R_ENCODE_HEADER_SIZE);
+        HDassert(p_buf_size_left > (H5_SIZEOF_UINT32_T + H5R_ENCODE_HEADER_SIZE));
+        p_buf_size_left -= (H5_SIZEOF_UINT32_T + H5R_ENCODE_HEADER_SIZE);
 
         /* Remove blob for old data */
         if(H5VL_blob_specific(dst_file, (void *)p_bg, H5VL_BLOB_DELETE) < 0)
@@ -678,6 +833,48 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5T__ref_obj_disk_isnull
+ *
+ * Purpose: Check if it's a NULL / uninitialized reference.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t H5T__ref_obj_disk_isnull(const H5VL_object_t *src_file,
+    const void *src_buf, hbool_t *isnull)
+{
+    H5F_t *src_f;
+    const uint8_t *p = (const uint8_t *)src_buf;
+    haddr_t addr;
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Check parameters */
+    HDassert(src_file);
+    HDassert(src_buf);
+    HDassert(isnull);
+
+    /* We should assert here that the terminal connector is H5VL_NATIVE once
+     * there is a facility to do so -NAF 2019/10/30 */
+
+    /* Retrieve file from VOL object */
+    if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")
+
+    /* Get the object address */
+    H5F_addr_decode(src_f, &p, &addr);
+
+    /* Check if heap address is 'nil' */
+    *isnull = (addr == 0) ? TRUE : FALSE;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* end H5T__ref_obj_disk_isnull() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5T__ref_obj_disk_getsize
  *
  * Purpose: Retrieves the length of a disk based reference.
@@ -749,7 +946,7 @@ H5T__ref_obj_disk_read(H5VL_object_t *src_file, const void *src_buf, size_t src_
 
     /* Get object address */
     if(H5R__decode_token_obj_compat((const unsigned char *)src_buf, &src_size,
-        (unsigned char *)dst_buf, H5F_SIZEOF_ADDR(src_f)) < 0)
+        (H5VL_token_t *)dst_buf, H5F_SIZEOF_ADDR(src_f)) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTDECODE, FAIL, "unable to get object address")
 
 done:
@@ -758,6 +955,49 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5T__ref_dsetreg_disk_isnull
+ *
+ * Purpose: Check if it's a NULL / uninitialized reference.
+ *
+ * Return:  Non-negative on success/Negative on failure
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5T__ref_dsetreg_disk_isnull(const H5VL_object_t *src_file, const void *src_buf,
+    hbool_t *isnull)
+{
+    H5F_t *src_f;
+    const uint8_t *p = (const uint8_t *)src_buf;
+    haddr_t addr;
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_STATIC
+
+    /* Check parameters */
+    HDassert(src_file);
+    HDassert(src_buf);
+    HDassert(isnull);
+
+    /* We should assert here that the terminal connector is H5VL_NATIVE once
+     * there is a facility to do so -NAF 2019/10/30 */
+
+    /* Retrieve file from VOL object */
+    if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid VOL object")
+
+    /* Get the heap address */
+    H5F_addr_decode(src_f, &p, &addr);
+
+    /* Check if heap address is 'nil' */
+    *isnull = (addr == 0) ? TRUE : FALSE;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+}   /* end H5T__ref_dsetreg_disk_isnull() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5T__ref_dsetreg_disk_getsize
  *
  * Purpose: Retrieves the length of a disk based reference.
@@ -767,28 +1007,28 @@ done:
  *-------------------------------------------------------------------------
  */
 static size_t
-H5T__ref_dsetreg_disk_getsize(H5VL_object_t H5_ATTR_UNUSED *file,
-    const void H5_ATTR_UNUSED *buf, size_t H5_ATTR_UNUSED buf_size,
+H5T__ref_dsetreg_disk_getsize(H5VL_object_t H5_ATTR_UNUSED *src_file,
+    const void H5_ATTR_UNUSED *src_buf, size_t H5_ATTR_UNUSED src_size,
     H5VL_object_t H5_ATTR_UNUSED *dst_file, hbool_t H5_ATTR_UNUSED *dst_copy)
 {
     size_t ret_value = sizeof(struct H5Tref_dsetreg);
 
     FUNC_ENTER_STATIC
 
-    HDassert(buf);
+    HDassert(src_buf);
 
 #ifndef NDEBUG
     {
-        H5F_t *f;
+        H5F_t *src_f;
 
         /* We should assert here that the terminal connector is H5VL_NATIVE once
          * there is a facility to do so -NAF 2019/10/30 */
 
         /* Retrieve file from VOL object */
-        if(NULL == (f = (H5F_t *)H5VL_object_data(file)))
+        if(NULL == (src_f = (H5F_t *)H5VL_object_data(src_file)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, 0, "invalid VOL object")
 
-        HDassert(buf_size == H5T_REF_DSETREG_DISK_SIZE(f));
+        HDassert(src_size == H5T_REF_DSETREG_DISK_SIZE(src_f));
     } /* end block */
 #endif /* NDEBUG */
 
diff --git a/src/H5VLconnector.h b/src/H5VLconnector.h
index 2dd8fbe..84e3b64 100644
--- a/src/H5VLconnector.h
+++ b/src/H5VLconnector.h
@@ -52,7 +52,9 @@
 
 /* type for tokens. Token are unique and permanent identifiers that are
  * used to reference HDF5 objects. */
-typedef unsigned char H5VL_token_t[H5VL_MAX_TOKEN_SIZE];
+typedef struct {
+    char __data[H5VL_MAX_TOKEN_SIZE];
+} H5VL_token_t;
 
 /* types for attribute GET callback */
 typedef enum H5VL_attr_get_t {
@@ -161,6 +163,7 @@ typedef enum H5VL_link_specific_t {
 
 /* types for object GET callback */
 typedef enum H5VL_object_get_t {
+    H5VL_OBJECT_GET_FILE,              /* object file                       */
     H5VL_OBJECT_GET_NAME,              /* object name                       */
     H5VL_OBJECT_GET_TYPE               /* object type                       */
 } H5VL_object_get_t;
@@ -212,7 +215,7 @@ typedef struct H5VL_loc_by_idx {
 } H5VL_loc_by_idx_t;
 
 typedef struct H5VL_loc_by_token {
-    void *token;
+    H5VL_token_t *token;
 } H5VL_loc_by_token_t;
 
 /* Structure to hold parameters for object locations.
diff --git a/src/H5VLnative.h b/src/H5VLnative.h
index 5b51e66..73cec8d 100644
--- a/src/H5VLnative.h
+++ b/src/H5VLnative.h
@@ -57,25 +57,24 @@ typedef int H5VL_native_file_optional_t;
 #define H5VL_NATIVE_FILE_GET_MDC_SIZE                   7   /* H5Fget_mdc_size                      */
 #define H5VL_NATIVE_FILE_GET_SIZE                       8   /* H5Fget_filesize                      */
 #define H5VL_NATIVE_FILE_GET_VFD_HANDLE                 9   /* H5Fget_vfd_handle                    */
-#define H5VL_NATIVE_FILE_GET_FILE_ID                    10  /* H5Fget_file_id                       */
-#define H5VL_NATIVE_FILE_RESET_MDC_HIT_RATE             11  /* H5Freset_mdc_hit_rate_stats          */
-#define H5VL_NATIVE_FILE_SET_MDC_CONFIG                 12  /* H5Fset_mdc_config                    */
-#define H5VL_NATIVE_FILE_GET_METADATA_READ_RETRY_INFO   13  /* H5Fget_metadata_read_retry_info      */
-#define H5VL_NATIVE_FILE_START_SWMR_WRITE               14  /* H5Fstart_swmr_write                  */
-#define H5VL_NATIVE_FILE_START_MDC_LOGGING              15  /* H5Fstart_mdc_logging                 */
-#define H5VL_NATIVE_FILE_STOP_MDC_LOGGING               16  /* H5Fstop_mdc_logging                  */
-#define H5VL_NATIVE_FILE_GET_MDC_LOGGING_STATUS         17  /* H5Fget_mdc_logging_status            */
-#define H5VL_NATIVE_FILE_FORMAT_CONVERT                 18  /* H5Fformat_convert                    */
-#define H5VL_NATIVE_FILE_RESET_PAGE_BUFFERING_STATS     19  /* H5Freset_page_buffering_stats        */
-#define H5VL_NATIVE_FILE_GET_PAGE_BUFFERING_STATS       20  /* H5Fget_page_buffering_stats          */
-#define H5VL_NATIVE_FILE_GET_MDC_IMAGE_INFO             21  /* H5Fget_mdc_image_info                */
-#define H5VL_NATIVE_FILE_GET_EOA                        22  /* H5Fget_eoa                           */
-#define H5VL_NATIVE_FILE_INCR_FILESIZE                  23  /* H5Fincrement_filesize                */
-#define H5VL_NATIVE_FILE_SET_LIBVER_BOUNDS              24  /* H5Fset_latest_format/libver_bounds   */
-#define H5VL_NATIVE_FILE_GET_MIN_DSET_OHDR_FLAG         25  /* H5Fget_dset_no_attrs_hint            */
-#define H5VL_NATIVE_FILE_SET_MIN_DSET_OHDR_FLAG         26  /* H5Fset_dset_no_attrs_hint            */
-#define H5VL_NATIVE_FILE_GET_MPI_ATOMICITY              27  /* H5Fget_mpi_atomicity                 */
-#define H5VL_NATIVE_FILE_SET_MPI_ATOMICITY              28  /* H5Fset_mpi_atomicity                 */
+#define H5VL_NATIVE_FILE_RESET_MDC_HIT_RATE             10  /* H5Freset_mdc_hit_rate_stats          */
+#define H5VL_NATIVE_FILE_SET_MDC_CONFIG                 11  /* H5Fset_mdc_config                    */
+#define H5VL_NATIVE_FILE_GET_METADATA_READ_RETRY_INFO   12  /* H5Fget_metadata_read_retry_info      */
+#define H5VL_NATIVE_FILE_START_SWMR_WRITE               13  /* H5Fstart_swmr_write                  */
+#define H5VL_NATIVE_FILE_START_MDC_LOGGING              14  /* H5Fstart_mdc_logging                 */
+#define H5VL_NATIVE_FILE_STOP_MDC_LOGGING               15  /* H5Fstop_mdc_logging                  */
+#define H5VL_NATIVE_FILE_GET_MDC_LOGGING_STATUS         16  /* H5Fget_mdc_logging_status            */
+#define H5VL_NATIVE_FILE_FORMAT_CONVERT                 17  /* H5Fformat_convert                    */
+#define H5VL_NATIVE_FILE_RESET_PAGE_BUFFERING_STATS     18  /* H5Freset_page_buffering_stats        */
+#define H5VL_NATIVE_FILE_GET_PAGE_BUFFERING_STATS       19  /* H5Fget_page_buffering_stats          */
+#define H5VL_NATIVE_FILE_GET_MDC_IMAGE_INFO             20  /* H5Fget_mdc_image_info                */
+#define H5VL_NATIVE_FILE_GET_EOA                        21  /* H5Fget_eoa                           */
+#define H5VL_NATIVE_FILE_INCR_FILESIZE                  22  /* H5Fincrement_filesize                */
+#define H5VL_NATIVE_FILE_SET_LIBVER_BOUNDS              23  /* H5Fset_latest_format/libver_bounds   */
+#define H5VL_NATIVE_FILE_GET_MIN_DSET_OHDR_FLAG         24  /* H5Fget_dset_no_attrs_hint            */
+#define H5VL_NATIVE_FILE_SET_MIN_DSET_OHDR_FLAG         25  /* H5Fset_dset_no_attrs_hint            */
+#define H5VL_NATIVE_FILE_GET_MPI_ATOMICITY              26  /* H5Fget_mpi_atomicity                 */
+#define H5VL_NATIVE_FILE_SET_MPI_ATOMICITY              27  /* H5Fset_mpi_atomicity                 */
 
 /* Typedef and values for native VOL connector group optional VOL operations */
 typedef int H5VL_native_group_optional_t;
diff --git a/src/H5VLnative_file.c b/src/H5VLnative_file.c
index 3703c05..588d59f 100644
--- a/src/H5VLnative_file.c
+++ b/src/H5VLnative_file.c
@@ -591,20 +591,6 @@ H5VL__native_file_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id, void H5_ATTR
                 break;
             }
 
-        /* H5Iget_file_id */
-        case H5VL_NATIVE_FILE_GET_FILE_ID:
-            {
-                H5I_type_t  type = (H5I_type_t)HDva_arg(arguments, int); /* enum work-around */
-                hbool_t     app_ref = (hbool_t)HDva_arg(arguments, int);
-                hid_t      *file_id = HDva_arg(arguments, hid_t *);
-
-                if(NULL == (f = H5F__get_file(obj, type)))
-                    HGOTO_ERROR(H5E_FILE, H5E_BADTYPE, FAIL, "not a file or file object")
-                if((*file_id = H5F__get_file_id(f, app_ref)) < 0)
-                    HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't get file ID")
-                break;
-            }
-
         /* H5Fclear_elink_file_cache */
         case H5VL_NATIVE_FILE_CLEAR_ELINK_CACHE:
             {
diff --git a/src/H5VLnative_object.c b/src/H5VLnative_object.c
index 675d8cf..6a22b05 100644
--- a/src/H5VLnative_object.c
+++ b/src/H5VLnative_object.c
@@ -16,10 +16,11 @@
  */
 
 #define H5O_FRIEND              /* Suppress error about including H5Opkg    */
+#define H5F_FRIEND              /* Suppress error about including H5Fpkg    */
 
 #include "H5private.h"          /* Generic Functions                        */
 #include "H5Eprivate.h"         /* Error handling                           */
-#include "H5Fprivate.h"         /* Files                                    */
+#include "H5Fpkg.h"             /* Files (pkg needed for id_exists)         */
 #include "H5Gprivate.h"         /* Groups                                   */
 #include "H5Iprivate.h"         /* IDs                                      */
 #include "H5Opkg.h"             /* Object headers                           */
@@ -150,6 +151,25 @@ H5VL__native_object_get(void *obj, const H5VL_loc_params_t *loc_params, H5VL_obj
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
 
     switch(get_type) {
+
+        /* Object file */
+        case H5VL_OBJECT_GET_FILE:
+            {
+                void **ret = HDva_arg(arguments, void **);
+
+                if(loc_params->type == H5VL_OBJECT_BY_SELF) {
+                    *ret = (void *)loc.oloc->file;
+
+                    /* TODO we currently need to set id_exists to TRUE because
+                     * the upper layer will create an ID from the returned
+                     * object. In theory this should not be needed and id_exists
+                     * should be removed once the H5Fmount code gets fixed. */
+                    loc.oloc->file->id_exists = TRUE;
+                } else
+                    HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "unknown get_file parameters")
+                break;
+            }
+
         /* Object name */
         case H5VL_OBJECT_GET_NAME:
             {
@@ -267,7 +287,7 @@ H5VL__native_object_specific(void *obj, const H5VL_loc_params_t *loc_params, H5V
         /* Lookup object */
         case H5VL_OBJECT_LOOKUP:
             {
-                void *token = va_arg(arguments, void *);
+                H5VL_token_t *token = va_arg(arguments, H5VL_token_t *);
 
                 HDassert(token);
 
diff --git a/src/H5trace.c b/src/H5trace.c
index 2f40686..74f6adf 100644
--- a/src/H5trace.c
+++ b/src/H5trace.c
@@ -2996,6 +2996,9 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
                             H5VL_object_get_t get = (H5VL_object_get_t)HDva_arg(ap, int);
 
                             switch(get) {
+                                case H5VL_OBJECT_GET_FILE:
+                                    HDfprintf(out, "H5VL_OBJECT_GET_FILE");
+                                    break;
                                 case H5VL_OBJECT_GET_NAME:
                                     HDfprintf(out, "H5VL_OBJECT_GET_NAME");
                                     break;