[svn-r27153] Implement fill value support for VDS.

Add testing for this.
Fix bug in printf string parsing.
Add test for this.
Other minor fixes/cleanup.

Tested: ummon

9 files changed, 1560 insertions, 1023 deletions

diff --git a/src/H5Dvirtual.c b/src/H5Dvirtual.c
index baaea16..fc88b6f 100644
--- a/src/H5Dvirtual.c
+++ b/src/H5Dvirtual.c
@@ -61,9 +61,6 @@
 /********************/
 
 /* Layout operation callbacks */
-static herr_t H5D__virtual_io_init(const H5D_io_info_t *io_info,
-    const H5D_type_info_t *type_info, hsize_t nelmts, const H5S_t *file_space,
-    const H5S_t *mem_space, H5D_chunk_map_t *cm);
 static herr_t H5D__virtual_read(H5D_io_info_t *io_info, const H5D_type_info_t
     *type_info, hsize_t nelmts, const H5S_t *file_space, const H5S_t *mem_space,
     H5D_chunk_map_t *fm);
@@ -88,12 +85,16 @@ static herr_t H5D__virtual_build_source_name(char *source_name,
     size_t nsubs, hsize_t blockno, char **built_name);
 static herr_t H5D__virtual_read_one(H5D_io_info_t *io_info,
     const H5D_type_info_t *type_info, const H5S_t *file_space,
-    const H5S_t *mem_space, H5O_storage_virtual_ent_t *virtual_ent,
+    H5O_storage_virtual_ent_t *virtual_ent,
     H5O_storage_virtual_srcdset_t *source_dset);
 static herr_t H5D__virtual_write_one(H5D_io_info_t *io_info,
     const H5D_type_info_t *type_info, const H5S_t *file_space,
-    const H5S_t *mem_space, H5O_storage_virtual_ent_t *virtual_ent,
+    H5O_storage_virtual_ent_t *virtual_ent,
     H5O_storage_virtual_srcdset_t *source_dset);
+static herr_t H5D__virtual_pre_io(H5D_io_info_t *io_info,
+    H5O_storage_virtual_t *storage, const H5S_t *file_space,
+    const H5S_t *mem_space, hsize_t *tot_nelmts);
+static herr_t H5D__virtual_post_io(H5O_storage_virtual_t *storage);
 
 
 /*********************/
@@ -105,7 +106,7 @@ const H5D_layout_ops_t H5D_LOPS_VIRTUAL[1] = {{
     NULL,
     H5D__virtual_init,
     H5D__virtual_is_space_alloc,
-    H5D__virtual_io_init,
+    NULL,
     H5D__virtual_read,
     H5D__virtual_write,
 #ifdef H5_HAVE_PARALLEL
@@ -502,6 +503,10 @@ H5D__virtual_reset_source_dset(H5O_storage_virtual_ent_t *virtual_ent,
         source_dset->virtual_select = NULL;
     } /* end if */
 
+    /* The projected memory space should never exist when this function is
+     * called */
+    HDassert(!source_dset->projected_mem_space);
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_reset_source_dset() */
 
@@ -523,7 +528,6 @@ static herr_t
 H5D__virtual_str_append(const char *src, size_t src_len, char **p, char **buf,
     size_t *buf_size)
 {
-    size_t      p_offset;               /* Offset of p within buf */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_STATIC
@@ -547,22 +551,26 @@ H5D__virtual_str_append(const char *src, size_t src_len, char **p, char **buf,
         *buf_size = src_len + (size_t)1;
         *p = *buf;
     } /* end if */
-    else if(((p_offset = (size_t)(*p - *buf)) + src_len + (size_t)1)
-            > *buf_size) {
-        char *tmp_buf;
-        size_t tmp_buf_size;
-
-        /* Calculate new size of buffer */
-        tmp_buf_size = MAX(p_offset + src_len + (size_t)1,
-                *buf_size * (size_t)2);
-
-        /* Reallocate buffer */
-        if(NULL == (tmp_buf = (char *)H5MM_realloc(*buf, tmp_buf_size)))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to reallocate name segment buffer")
-        *buf = tmp_buf;
-        *buf_size = tmp_buf_size;
-        *p = *buf + p_offset;
-    } /* end if */
+    else {
+        size_t p_offset = (size_t)(*p - *buf); /* Offset of p within buf */
+
+        /* Extend buffer if necessary */
+        if((p_offset + src_len + (size_t)1) > *buf_size) {
+            char *tmp_buf;
+            size_t tmp_buf_size;
+
+            /* Calculate new size of buffer */
+            tmp_buf_size = MAX(p_offset + src_len + (size_t)1,
+                    *buf_size * (size_t)2);
+
+            /* Reallocate buffer */
+            if(NULL == (tmp_buf = (char *)H5MM_realloc(*buf, tmp_buf_size)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to reallocate name segment buffer")
+            *buf = tmp_buf;
+            *buf_size = tmp_buf_size;
+            *p = *buf + p_offset;
+        } /* end if */
+    } /* end else */
 
     /* Copy string to *p.  Note that since src in not NULL terminated, we must
      * use memcpy */
@@ -730,8 +738,12 @@ H5D__virtual_copy_parsed_name(H5O_storage_virtual_name_seg_t **dst,
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to allocate name segment struct")
 
         /* Duplicate name segment */
-        if(NULL == ((*p_dst)->name_segment = HDstrdup(p_src->name_segment)))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to duplicate name segment")
+        if(p_src->name_segment) {
+            if(NULL == ((*p_dst)->name_segment = HDstrdup(p_src->name_segment)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to duplicate name segment")
+        } /* end if */
+        else
+            (*p_dst)->name_segment = NULL;
 
         /* Advance pointers */
         p_src = p_src->next;
@@ -1281,28 +1293,226 @@ H5D__virtual_is_space_alloc(const H5O_storage_t UNUSED *storage)
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5D__virtual_io_init
+ * Function:    H5D__virtual_pre_io
  *
- * Purpose:     Performs initialization before any sort of I/O on the raw data
+ * Purpose:     Project all virtual mappings onto mem_space, with the
+ *              results stored in projected_mem_space for each mapping.
+ *              Opens all source datasets if possible.  The total number
+ *              of elements is stored in tot_nelmts.
  *
  * Return:      Non-negative on success/Negative on failure
  *
  * Programmer:  Neil Fortner
- *              February 6, 2015
+ *              June 3, 2015
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5D__virtual_io_init(const H5D_io_info_t UNUSED *io_info, const H5D_type_info_t UNUSED *type_info,
-    hsize_t UNUSED nelmts, const H5S_t UNUSED *file_space, const H5S_t UNUSED *mem_space,
-    H5D_chunk_map_t UNUSED *cm)
+H5D__virtual_pre_io(H5D_io_info_t *io_info,
+    H5O_storage_virtual_t *storage, const H5S_t *file_space,
+    const H5S_t *mem_space, hsize_t *tot_nelmts)
 {
-    FUNC_ENTER_STATIC_NOERR
+    H5S_t       *tmp_space = NULL;          /* Copied virtual_select VDSINC */
+    hssize_t    select_nelmts;              /* Number of elements in selection */
+    size_t      i, j;                       /* Local index variables */
+    herr_t      ret_value = SUCCEED;        /* Return value */
 
-    /* No-op for now.  Delete if we never add anything here. VDSINC */
+    FUNC_ENTER_STATIC
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5D__virtual_io_init() */
+    /* Sanity check */
+    HDassert(storage);
+    HDassert(mem_space);
+    HDassert(file_space);
+    HDassert(tot_nelmts);
+
+    /* Initialize tot_nelmts */
+    *tot_nelmts = 0;
+
+    /* Iterate over mappings */
+    for(i = 0; i < storage->list_nused; i++) {
+        /* Sanity check that the virtual space has been patched by now */
+        HDassert(storage->list[i].virtual_space_status == H5O_VIRTUAL_STATUS_CORRECT);
+
+        /* Check for "printf" source dataset resolution */
+        if(storage->list[i].parsed_source_file_name
+                || storage->list[i].parsed_source_dset_name) {
+            /* Iterate over sub-source dsets */
+            for(j = 0; j < storage->list[i].sub_dset_nused; j++) {
+                H5S_t       *virtual_select;            /* Pointer to real virtual_select VDSINC */
+
+                /* Quick hack to make this work with printf VDSINC */
+                if(storage->view == H5D_VDS_LAST_AVAILABLE) {
+                    virtual_select = storage->list[i].sub_dset[j].virtual_select;
+                } /* end if */
+                else {
+                    hsize_t start[H5S_MAX_RANK];
+                    hsize_t count[H5S_MAX_RANK];
+
+                    /* Quick hack to make this work with FIRST_MISSING */
+                    /* Copy virtual selection */
+                    if(NULL == (tmp_space = H5S_copy(storage->list[i].sub_dset[j].virtual_select, FALSE, TRUE)))
+                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "can't copy virtual selection")
+
+                    /* Get virtual extent dimensions */
+                    if(H5S_get_simple_extent_dims(tmp_space, count, NULL) < 0)
+                        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get virtual dataspace dimensions")
+
+                    /* Set start to zeroes */
+                    (void)HDmemset(start, 0, sizeof(start));
+
+                    /* Clip tmp_space selection to extent */
+                    if(H5S_select_hyperslab(tmp_space, H5S_SELECT_AND, start, NULL, count, NULL) < 0)
+                        HGOTO_ERROR(H5E_DATASET, H5E_CANTSELECT, FAIL, "can't clip selection to extent")
+
+                    /* Check for no elements selected */
+                    if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(tmp_space)) < 0)
+                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")
+                    if(select_nelmts == 0) {
+                        if(H5S_close(tmp_space) < 0)
+                            HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close temporary space")
+                        tmp_space = NULL;
+                        continue;
+                    } /* end if */
+
+                    virtual_select = tmp_space;
+                } /* end else */
+
+                /* Project intersection of file space and mapping virtual space onto
+                 * memory space */
+                if(H5S_select_project_intersection(file_space, mem_space, virtual_select, &storage->list[i].sub_dset[j].projected_mem_space) < 0)
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto memory space")
+
+                /* Close temporary space VDSINC */
+                if(tmp_space) {
+                    if(H5S_close(tmp_space) < 0)
+                        HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close temporary space")
+                    tmp_space = NULL;
+                } /* end if */
+
+                /* Check number of elements selected */
+                if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(storage->list[i].sub_dset[j].projected_mem_space)) < 0)
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")
+
+                /* Check if anything is selected */
+                if(select_nelmts > (hssize_t)0) {
+                    /* Open source dataset */
+                    if(!storage->list[i].sub_dset[j].dset)
+                        /* Try to open dataset */
+                        if(H5D__virtual_open_source_dset(io_info->dset, &storage->list[i], &storage->list[i].sub_dset[j], io_info->dxpl_id) < 0)
+                            HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")
+
+                    /* If the source dataset is not open, mark the selected
+                     * elements as zero so projected_mem_space is freed */
+                    if(!storage->list[i].sub_dset[j].dset)
+                        select_nelmts = (hssize_t)0;
+                } /* end if */
+
+                /* If there are not elements selected in this mapping, free
+                 * projected_mem_space, otherwise update tot_nelmts */
+                if(select_nelmts == (hssize_t)0) {
+                    if(H5S_close(storage->list[i].sub_dset[j].projected_mem_space) < 0)
+                        HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected memory space")
+                    storage->list[i].sub_dset[j].projected_mem_space = NULL;
+                } /* end if */
+                else 
+                    *tot_nelmts += (hsize_t)select_nelmts;
+            } /* end for */
+        } /* end if */
+        else {
+            /* Project intersection of file space and mapping virtual space onto
+             * memory space */
+            if(H5S_select_project_intersection(file_space, mem_space, storage->list[i].source_dset.virtual_select, &storage->list[i].source_dset.projected_mem_space) < 0)
+                HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto memory space")
+
+            /* Check number of elements selected, add to tot_nelmts */
+            if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(storage->list[i].source_dset.projected_mem_space)) < 0)
+                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")
+
+            /* Check if anything is selected */
+            if(select_nelmts > (hssize_t)0) {
+                /* Open source dataset */
+                if(!storage->list[i].source_dset.dset) 
+                    /* Try to open dataset */
+                    if(H5D__virtual_open_source_dset(io_info->dset, &storage->list[i], &storage->list[i].source_dset, io_info->dxpl_id) < 0)
+                        HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")
+
+                /* If the source dataset is not open, mark the selected elements
+                 * as zero so projected_mem_space is freed */
+                if(!storage->list[i].source_dset.dset) {
+                    HDassert(0 && "Checking code coverage..."); //VDSINC
+                    select_nelmts = (hssize_t)0;
+                } //VDSINC
+            } /* end if */
+
+            /* If there are not elements selected in this mapping, free
+             * projected_mem_space, otherwise update tot_nelmts */
+            if(select_nelmts == (hssize_t)0) {
+                if(H5S_close(storage->list[i].source_dset.projected_mem_space) < 0)
+                    HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected memory space")
+                storage->list[i].source_dset.projected_mem_space = NULL;
+            } /* end if */
+            else
+                *tot_nelmts += (hsize_t)select_nelmts;
+        } /* end else */
+    } /* end for */
+
+done:
+    /* Release tmp_space VDSINC */
+    if(tmp_space)
+        if(H5S_close(tmp_space) < 0)
+            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close temporary space")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D__virtual_pre_io() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5D__virtual_post_io
+ *
+ * Purpose:     VDSINC
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              June 4, 2015
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5D__virtual_post_io(H5O_storage_virtual_t *storage)
+{
+    size_t      i, j;                       /* Local index variables */
+    herr_t      ret_value = SUCCEED;        /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(storage);
+
+    /* Iterate over mappings */
+    for(i = 0; i < storage->list_nused; i++)
+        /* Check for "printf" source dataset resolution */
+        if(storage->list[i].parsed_source_file_name
+                || storage->list[i].parsed_source_dset_name) {
+            /* Iterate over sub-source dsets */
+            for(j = 0; j < storage->list[i].sub_dset_nused; j++)
+                /* Close projected memory space */
+                if(storage->list[i].sub_dset[j].projected_mem_space) {
+                    if(H5S_close(storage->list[i].sub_dset[j].projected_mem_space) < 0)
+                        HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close temporary space")
+                    storage->list[i].sub_dset[j].projected_mem_space = NULL;
+                } /* end if */
+        } /* end if */
+        else
+            /* Close projected memory space */
+            if(storage->list[i].source_dset.projected_mem_space) {
+                if(H5S_close(storage->list[i].source_dset.projected_mem_space) < 0)
+                    HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close temporary space")
+                storage->list[i].source_dset.projected_mem_space = NULL;
+            } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D__virtual_post_io() */
 
 
 /*-------------------------------------------------------------------------
@@ -1319,13 +1529,10 @@ H5D__virtual_io_init(const H5D_io_info_t UNUSED *io_info, const H5D_type_info_t
  */
 static herr_t
 H5D__virtual_read_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
-    const H5S_t *file_space, const H5S_t *mem_space,
-    H5O_storage_virtual_ent_t *virtual_ent,
+    const H5S_t *file_space, H5O_storage_virtual_ent_t *virtual_ent,
     H5O_storage_virtual_srcdset_t *source_dset)
 {
-    H5S_t       *projected_mem_space = NULL; /* Memory space for selection in a single mapping */
     H5S_t       *projected_src_space = NULL; /* File space for selection in a single source dataset */
-    hssize_t    select_nelmts;              /* Number of elements in selection */
     H5S_t       *tmp_space = NULL;          /* Copied virtual_select VDSINC */
     H5S_t       *virtual_select;            /* Pointer to real virtual_select VDSINC */
     herr_t      ret_value = SUCCEED;        /* Return value */
@@ -1336,12 +1543,14 @@ H5D__virtual_read_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     HDassert(source_dset);
 
     /* Quick hack to make this work with printf VDSINC */
-    if(source_dset == &virtual_ent->source_dset) {
+    if((source_dset == &virtual_ent->source_dset)
+            || (io_info->dset->shared->layout.storage.u.virt.view == H5D_VDS_LAST_AVAILABLE)) {
         virtual_select = source_dset->virtual_select;
     } /* end if */
     else {
         hsize_t start[H5S_MAX_RANK];
         hsize_t count[H5S_MAX_RANK];
+        hssize_t select_nelmts;
 
         /* Copy virtual selection */
         if(NULL == (tmp_space = H5S_copy(source_dset->virtual_select, FALSE, TRUE)))
@@ -1367,63 +1576,37 @@ H5D__virtual_read_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
         virtual_select = tmp_space;
     } /* end else */
 
-    /* Project intersection of file space and mapping virtual space onto
-     * memory space */
-    if(H5S_select_project_intersection(file_space, mem_space, virtual_select, &projected_mem_space) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto memory space")
+    /* Only perform I/O if there is a projected memory space, otherwise there
+     * were no elements in the projection or the source dataset could not be
+     * opened */
+    if(source_dset->projected_mem_space) {
+        HDassert(source_dset->dset);
 
-    /* Get number of elements in projected dataspace */
-    if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(projected_mem_space)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")
+        /* Sanity check that the source space has been patched by now */
+        HDassert(virtual_ent->source_space_status == H5O_VIRTUAL_STATUS_CORRECT);
 
-    /* Only perform I/O if there are any elements */
-    if(select_nelmts > 0) {
-        /* Open source dataset */
-        if(!source_dset->dset)
-            /* Try to open dataset */
-            if(H5D__virtual_open_source_dset(io_info->dset, virtual_ent, source_dset, io_info->dxpl_id) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")
+        /* Project intersection of file space and mapping virtual space onto
+         * mapping source space */
+        if(H5S_select_project_intersection(virtual_select, virtual_ent->source_select, file_space, &projected_src_space) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto source space")
 
-        /* Check if source dataset is open */
-        if(source_dset->dset) {
-            /* Sanity check that the source space has been patched by now */
-            HDassert(virtual_ent->source_space_status == H5O_VIRTUAL_STATUS_CORRECT);
+        /* Perform read on source dataset */
+        if(H5D__read(source_dset->dset, type_info->dst_type_id, source_dset->projected_mem_space, projected_src_space, io_info->dxpl_id, io_info->u.rbuf) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "can't read source dataset")
 
-            /* Project intersection of file space and mapping virtual space onto
-             * mapping source space */
-            if(H5S_select_project_intersection(virtual_select, virtual_ent->source_select, file_space, &projected_src_space) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto source space")
-
-            /* Perform read on source dataset */
-            if(H5D__read(source_dset->dset, type_info->dst_type_id, projected_mem_space, projected_src_space, io_info->dxpl_id, io_info->u.rbuf) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "can't read source dataset")
-
-            /* Close projected_src_space */
-            if(H5S_close(projected_src_space) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
-            projected_src_space = NULL;
-        } /* end if */
+        /* Close projected_src_space */
+        if(H5S_close(projected_src_space) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
+        projected_src_space = NULL;
     } /* end if */
 
-    /* Close projected_mem_space */
-    if(H5S_close(projected_mem_space) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected memory space")
-    projected_mem_space = NULL;
-
 done:
     /* Release allocated resources on failure */
-    if(ret_value < 0) {
-        if(projected_src_space)
-            if(H5S_close(projected_src_space) < 0)
-                HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
-        if(projected_mem_space)
-            if(H5S_close(projected_mem_space) < 0)
-                HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected memory space")
+    if(projected_src_space) {
+        HDassert(ret_value < 0);
+        if(H5S_close(projected_src_space) < 0)
+            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
     } /* end if */
-    else {
-        HDassert(!projected_src_space);
-        HDassert(!projected_mem_space);
-    } /* end else */
 
     /* Release tmp_space VDSINC */
     if(tmp_space)
@@ -1452,6 +1635,8 @@ H5D__virtual_read(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     H5D_chunk_map_t UNUSED *fm)
 {
     H5O_storage_virtual_t *storage;         /* Convenient pointer into layout struct */
+    hsize_t     tot_nelmts;                 /* Total number of elements mapped to mem_space */
+    H5S_t       *fill_space = NULL;         /* Space to fill with fill value */
     size_t      i, j;                       /* Local index variables */
     herr_t      ret_value = SUCCEED;        /* Return value */
 
@@ -1467,6 +1652,10 @@ H5D__virtual_read(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     storage = &io_info->dset->shared->layout.storage.u.virt;
     HDassert((storage->view == H5D_VDS_FIRST_MISSING) || (storage->view == H5D_VDS_LAST_AVAILABLE));
 
+    /* Prepare for I/O operation */
+    if(H5D__virtual_pre_io(io_info, storage, file_space, mem_space, &tot_nelmts) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "unable to prepare for I/O operation")
+
     /* Iterate over mappings */
     for(i = 0; i < storage->list_nused; i++) {
         /* Sanity check that the virtual space has been patched by now */
@@ -1477,19 +1666,70 @@ H5D__virtual_read(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
                 || storage->list[i].parsed_source_dset_name) {
             /* Iterate over sub-source dsets */
             for(j = 0; j < storage->list[i].sub_dset_nused; j++)
-                if(H5D__virtual_read_one(io_info, type_info, file_space, mem_space, &storage->list[i], &storage->list[i].sub_dset[j]) < 0)
+                if(H5D__virtual_read_one(io_info, type_info, file_space, &storage->list[i], &storage->list[i].sub_dset[j]) < 0)
                     HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "unable to read source dataset")
         } /* end if */
         else
             /* Read from source dataset */
-            if(H5D__virtual_read_one(io_info, type_info, file_space, mem_space, &storage->list[i], &storage->list[i].source_dset) < 0)
+            if(H5D__virtual_read_one(io_info, type_info, file_space, &storage->list[i], &storage->list[i].source_dset) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "unable to read source dataset")
     } /* end for */
 
-    /* Fill unmapped part of buffer with fill value.  Keep track of total number
-     * elements written to memory buffer and assert that it == nelmts VDSINC */
+    /* Fill unmapped part of buffer with fill value */
+    if(tot_nelmts != nelmts) {
+        HDassert(tot_nelmts < nelmts);
+
+        /* Start with fill space equal to memory space */
+        if(NULL == (fill_space = H5S_copy(mem_space, FALSE, TRUE)))
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTCOPY, FAIL, "unable to copy memory selection")
+
+        /* Iterate over mappings */
+        for(i = 0; i < storage->list_nused; i++)
+            /* Check for "printf" source dataset resolution */
+            if(storage->list[i].parsed_source_file_name
+                    || storage->list[i].parsed_source_dset_name) {
+                /* Iterate over sub-source dsets */
+                for(j = 0; j < storage->list[i].sub_dset_nused; j++)
+                    if(storage->list[i].sub_dset[j].projected_mem_space)
+                        if(H5S_select_subtract(fill_space, storage->list[i].sub_dset[j].projected_mem_space) < 0)
+                            HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "unable to clip fill selection")
+            } /* end if */
+            else
+                if(storage->list[i].source_dset.projected_mem_space)
+                    /* Subtract projected memory space from fill space */
+                    if(H5S_select_subtract(fill_space, storage->list[i].source_dset.projected_mem_space) < 0)
+                        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "unable to clip fill selection")
+
+        /* Write fill values to memory buffer */
+        if(H5D__fill(io_info->dset->shared->dcpl_cache.fill.buf, io_info->dset->shared->type, io_info->u.rbuf, type_info->mem_type, fill_space, io_info->dxpl_id) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "filling buf failed")
+
+#ifndef NDEBUG
+        /* Make sure the total number of elements written (including fill
+         * values) == nelmts */
+        {
+            hssize_t    select_nelmts;  /* Number of elements in selection */
+
+            /* Get number of elements in fill dataspace */
+            if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(fill_space)) < 0)
+                HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")
+
+            /* Verify number of elements is correct */
+            HDassert((tot_nelmts + (hsize_t)select_nelmts) == nelmts);
+        } /* end block */
+#endif /* NDEBUG */
+    } /* end if */
 
 done:
+    /* Cleanup I/O operation */
+    if(H5D__virtual_post_io(storage) < 0)
+        HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't cleanup I/O operation")
+
+    /* Close fill space */
+    if(fill_space)
+        if(H5S_close(fill_space) < 0)
+            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close fill space")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_read() */
 
@@ -1508,13 +1748,10 @@ done:
  */
 static herr_t
 H5D__virtual_write_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
-    const H5S_t *file_space, const H5S_t *mem_space,
-    H5O_storage_virtual_ent_t *virtual_ent,
+    const H5S_t *file_space, H5O_storage_virtual_ent_t *virtual_ent,
     H5O_storage_virtual_srcdset_t *source_dset)
 {
-    H5S_t       *projected_mem_space = NULL; /* Memory space for selection in a single mapping */
     H5S_t       *projected_src_space = NULL; /* File space for selection in a single source dataset */
-    hssize_t    select_nelmts;              /* Number of elements in selection */
     herr_t      ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_STATIC
@@ -1522,25 +1759,10 @@ H5D__virtual_write_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     HDassert(virtual_ent);
     HDassert(source_dset);
 
-    /* Project intersection of file space and mapping virtual space onto
-     * memory space */
-    if(H5S_select_project_intersection(file_space, mem_space, source_dset->virtual_select, &projected_mem_space) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto memory space")
-
-    /* Get number of elements in projected dataspace */
-    if((select_nelmts = (hssize_t)H5S_GET_SELECT_NPOINTS(projected_mem_space)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTCOUNT, FAIL, "unable to get number of elements in selection")
-
-    /* Only perform I/O if there are any elements */
-    if(select_nelmts > 0) {
-        /* Open source dataset */
-        if(!source_dset->dset) {
-            /* Try to open dataset */
-            if(H5D__virtual_open_source_dset(io_info->dset, virtual_ent, source_dset, io_info->dxpl_id) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open source dataset")
-            if(!source_dset->dset)
-                HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "did not open source dataset")
-        } /* end if */
+    /* Only perform I/O if there is a projected memory space, otherwise there
+     * were no elements in the projection */
+    if(source_dset->projected_mem_space) {
+        HDassert(source_dset->dset);
 
         /* Sanity check that the source space has been patched by now */
         HDassert(virtual_ent->source_space_status == H5O_VIRTUAL_STATUS_CORRECT);
@@ -1553,7 +1775,7 @@ H5D__virtual_write_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
             HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "can't project virtual intersection onto source space")
 
         /* Perform write on source dataset */
-        if(H5D__write(source_dset->dset, type_info->dst_type_id, projected_mem_space, projected_src_space, io_info->dxpl_id, io_info->u.wbuf) < 0)
+        if(H5D__write(source_dset->dset, type_info->dst_type_id, source_dset->projected_mem_space, projected_src_space, io_info->dxpl_id, io_info->u.wbuf) < 0)
             HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "can't write to source dataset")
 
         /* Close projected_src_space */
@@ -1562,11 +1784,6 @@ H5D__virtual_write_one(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
         projected_src_space = NULL;
     } /* end if */
 
-    /* Close projected_mem_space */
-    if(H5S_close(projected_mem_space) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected memory space")
-    projected_mem_space = NULL;
-
 done:
     /* Release allocated resources on failure */
     if(projected_src_space) {
@@ -1574,11 +1791,6 @@ done:
         if(H5S_close(projected_src_space) < 0)
             HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected source space")
     } /* end if */
-    if(projected_mem_space) {
-        HDassert(ret_value < 0);
-        if(H5S_close(projected_mem_space) < 0)
-            HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't close projected memory space")
-    } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_write_one() */
@@ -1602,6 +1814,7 @@ H5D__virtual_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     H5D_chunk_map_t UNUSED *fm)
 {
     H5O_storage_virtual_t *storage;         /* Convenient pointer into layout struct */
+    hsize_t     tot_nelmts;                 /* Total number of elements mapped to mem_space */
     size_t      i, j;                       /* Local index variable */
     herr_t      ret_value = SUCCEED;        /* Return value */
 
@@ -1617,6 +1830,17 @@ H5D__virtual_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     storage = &io_info->dset->shared->layout.storage.u.virt;
     HDassert((storage->view == H5D_VDS_FIRST_MISSING) || (storage->view == H5D_VDS_LAST_AVAILABLE));
 
+    /* Prepare for I/O operation */
+    if(H5D__virtual_pre_io(io_info, storage, file_space, mem_space, &tot_nelmts) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTCLIP, FAIL, "unable to prepare for I/O operation")
+
+    /* Fail if there are unmapped parts of the selection as they would not be
+     * written */
+    if(tot_nelmts != nelmts) {
+        HDassert(0 && "Checking code coverage..."); //VDSINC
+        HGOTO_ERROR(H5E_DATASPACE, H5E_BADVALUE, FAIL, "write requested to unmapped portion of virtual dataset")
+    } //VDSINC
+
     /* Iterate over mappings */
     for(i = 0; i < storage->list_nused; i++) {
         /* Sanity check that virtual space has been patched by now */
@@ -1628,20 +1852,21 @@ H5D__virtual_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
             /* Iterate over sub-source dsets */
             for(j = 0; j < storage->list[i].sub_dset_nused; j++) {
                 HDassert(0 && "Checking code coverage..."); //VDSINC
-                if(H5D__virtual_write_one(io_info, type_info, file_space, mem_space, &storage->list[i], &storage->list[i].sub_dset[j]) < 0)
+                if(H5D__virtual_write_one(io_info, type_info, file_space, &storage->list[i], &storage->list[i].sub_dset[j]) < 0)
                     HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "unable to write to source dataset")
             } //VDSINC
         } /* end if */
         else
             /* Write to source dataset */
-            if(H5D__virtual_write_one(io_info, type_info, file_space, mem_space, &storage->list[i], &storage->list[i].source_dset) < 0)
+            if(H5D__virtual_write_one(io_info, type_info, file_space, &storage->list[i], &storage->list[i].source_dset) < 0)
                 HGOTO_ERROR(H5E_DATASET, H5E_READERROR, FAIL, "unable to write to source dataset")
     } /* end for */
 
-    /* Keep track of total number elements written to disk buffer and issure
-     * error if it != nelmts VDSINC */
-
 done:
+    /* Cleanup I/O operation */
+    if(H5D__virtual_post_io(storage) < 0)
+        HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "can't cleanup I/O operation")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5D__virtual_write() */
 
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index 6dc39d4..7063de5 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -420,6 +420,9 @@ typedef struct H5O_storage_virtual_srcdset_t {
 
     /* Not stored */
     struct H5D_t *dset;                 /* Source dataset                     */
+
+    /* Temporary - only used during I/O operation, NULL at all other times */
+    struct H5S_t *projected_mem_space;  /* Selection within mem_space for this mapping */
 } H5O_storage_virtual_srcdset_t;
 
 typedef struct H5O_storage_virtual_name_seg_t {
diff --git a/src/H5Shyper.c b/src/H5Shyper.c
index 399d009..87fb3a9 100644
--- a/src/H5Shyper.c
+++ b/src/H5Shyper.c
@@ -9627,6 +9627,116 @@ done:
 
 /*--------------------------------------------------------------------------
  NAME
+    H5S__hyper_subtract
+ PURPOSE
+    VDSINC
+ USAGE
+    VDSINC
+ RETURNS
+    Non-negative on success/Negative on failure.
+ DESCRIPTION
+    VDSINC
+
+    Note this function basically duplicates a subset of the functionality
+    of H5S_select_select().  It should probably be removed when that
+    function is enabled.
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5S__hyper_subtract (H5S_t *space, H5S_t *subtract_space)
+{
+    H5S_hyper_span_info_t *a_not_b = NULL;  /* Span tree for hyperslab spans in old span tree and not in new span tree */
+    H5S_hyper_span_info_t *a_and_b = NULL;  /* Span tree for hyperslab spans in both old and new span trees */
+    H5S_hyper_span_info_t *b_not_a = NULL;  /* Span tree for hyperslab spans in new span tree and not in old span tree */
+    herr_t      ret_value = SUCCEED;        /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Check args */
+    HDassert(space);
+    HDassert(subtract_space);
+
+    /* Check that the space selections both have span trees */
+    if(space->select.sel_info.hslab->span_lst == NULL)
+        if(H5S_hyper_generate_spans(space) < 0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_UNINITIALIZED, FAIL, "dataspace does not have span tree")
+    if(subtract_space->select.sel_info.hslab->span_lst == NULL)
+        if(H5S_hyper_generate_spans(subtract_space) < 0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_UNINITIALIZED, FAIL, "dataspace does not have span tree")
+
+    /* Generate lists of spans which overlap and don't overlap */
+    if(H5S_hyper_clip_spans(space->select.sel_info.hslab->span_lst, subtract_space->select.sel_info.hslab->span_lst, &a_not_b, &a_and_b, &b_not_a)<0)
+        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCLIP, FAIL, "can't clip hyperslab information")
+
+    /* Reset the other dataspace selection information */
+    if(H5S_SELECT_RELEASE(space) < 0)
+        HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't release selection")
+
+    /* Allocate space for the hyperslab selection information */
+    if((space->select.sel_info.hslab = H5FL_CALLOC(H5S_hyper_sel_t)) == NULL)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "can't allocate hyperslab info")
+
+    /* Set unlim_dim */
+    space->select.sel_info.hslab->unlim_dim = -1;
+
+    /* Check for anything returned in a_not_b */
+    if(a_not_b) {
+        /* Update spans in space */
+        space->select.sel_info.hslab->span_lst = a_not_b;
+        a_not_b = NULL;
+
+        /* Update number of elements */
+        space->select.num_elem = H5S_hyper_spans_nelem(space->select.sel_info.hslab->span_lst);
+
+        /* Attempt to rebuild "optimized" start/stride/count/block information.
+         * from resulting hyperslab span tree */
+        if(H5S_hyper_rebuild(space) < 0)
+            HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCOUNT, FAIL, "can't rebuild hyperslab info")
+    } /* end if */
+    else {
+        H5S_hyper_span_info_t *spans;     /* Empty hyperslab span tree */
+
+        HDassert(0 && "Checking code coverage..."); //VDSINC
+        /* Set number of elements */
+        space->select.num_elem = 0;
+
+        /* Allocate a span info node */
+        if(NULL == (spans = H5FL_MALLOC(H5S_hyper_span_info_t)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't allocate hyperslab span")
+
+        /* Set the reference count */
+        spans->count = 1;
+
+        /* Reset the scratch pad space */
+        spans->scratch = 0;
+
+        /* Set to empty tree */
+        spans->head = NULL;
+
+        /* Set pointer to empty span tree */
+        space->select.sel_info.hslab->span_lst = spans;
+    } /* end if */
+
+done:
+    /* Free span trees */
+    if(a_and_b)
+        H5S_hyper_free_span_info(a_and_b);
+    if(b_not_a)
+        H5S_hyper_free_span_info(b_not_a);
+    if(a_not_b) {
+        HDassert(ret_value < 0);
+        H5S_hyper_free_span_info(b_not_a);
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5S__hyper_subtract() */
+
+
+/*--------------------------------------------------------------------------
+ NAME
     H5S__hyper_get_clip_diminfo
  PURPOSE
     Calculates the count and block required to clip the specified
diff --git a/src/H5Spkg.h b/src/H5Spkg.h
index 77ca954..1359b00 100644
--- a/src/H5Spkg.h
+++ b/src/H5Spkg.h
@@ -276,6 +276,7 @@ H5_DLL herr_t H5S_extent_copy_real(H5S_extent_t *dst, const H5S_extent_t *src,
 H5_DLL herr_t H5S__hyper_project_intersection(const H5S_t *src_space,
     const H5S_t *dst_space, const H5S_t *src_intersect_space,
     H5S_t *proj_space);
+H5_DLL herr_t H5S__hyper_subtract (H5S_t *space, H5S_t *subtract_space);
 
 /* Testing functions */
 #ifdef H5S_TESTING
diff --git a/src/H5Sprivate.h b/src/H5Sprivate.h
index 342a9cc..976c968 100644
--- a/src/H5Sprivate.h
+++ b/src/H5Sprivate.h
@@ -241,6 +241,7 @@ H5_DLL herr_t H5S_select_project_simple(const H5S_t *space, H5S_t *new_space, hs
 H5_DLL herr_t H5S_select_project_intersection(const H5S_t *src_space,
     const H5S_t *dst_space, const H5S_t *src_intersect_space,
     H5S_t **new_space_ptr);
+H5_DLL herr_t H5S_select_subtract(H5S_t *space, H5S_t *subtract_space);
 
 /* Operations on all selections */
 H5_DLL herr_t H5S_select_all(H5S_t *space, hbool_t rel_prev);
diff --git a/src/H5Sselect.c b/src/H5Sselect.c
index c120769..0af3dfa 100644
--- a/src/H5Sselect.c
+++ b/src/H5Sselect.c
@@ -2259,3 +2259,92 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5S_select_project_intersection() */
 
+
+/*--------------------------------------------------------------------------
+ NAME
+    H5S_select_subtract
+
+ PURPOSE
+    VDSINC
+
+ USAGE
+    VDSINC
+
+ RETURNS
+    Non-negative on success/Negative on failure.
+
+ DESCRIPTION
+    VDSINC
+    
+ GLOBAL VARIABLES
+ COMMENTS, BUGS, ASSUMPTIONS
+ EXAMPLES
+ REVISION LOG
+--------------------------------------------------------------------------*/
+herr_t
+H5S_select_subtract(H5S_t *space, H5S_t *subtract_space)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(space);
+    HDassert(subtract_space);
+
+    /* If either space is using the none selection, then we do not need to do
+     * anything */
+    if((space->select.type->type != H5S_SEL_NONE)
+            && (subtract_space->select.type->type != H5S_SEL_NONE)) {
+        /* If subtract_space is using the all selection, set space to none */
+        if(subtract_space->select.type->type == H5S_SEL_ALL) {
+            HDassert(0 && "Checking code coverage...");//VDSINC
+            /* Change to "none" selection */
+            if(H5S_select_none(space) < 0)
+                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTDELETE, FAIL, "can't change selection")
+        } /* end if */
+        else {
+            /* Check for point selection in subtract_space, convert to
+             * hyperslab */
+            if(subtract_space->select.type->type == H5S_SEL_POINTS)
+                HDassert(0 && "Not yet implemented...");//VDSINC
+
+            /* Check for point or all selection in space, convert to hyperslab
+             */
+            if(space->select.type->type == H5S_SEL_ALL) {
+                /* Convert current "all" selection to "real" hyperslab selection */
+                /* Then allow operation to proceed */
+                hsize_t tmp_start[H5O_LAYOUT_NDIMS];    /* Temporary start information */
+                hsize_t tmp_stride[H5O_LAYOUT_NDIMS];   /* Temporary stride information */
+                hsize_t tmp_count[H5O_LAYOUT_NDIMS];    /* Temporary count information */
+                hsize_t tmp_block[H5O_LAYOUT_NDIMS];    /* Temporary block information */
+                unsigned i;                             /* Local index variable */
+
+                /* Fill in temporary information for the dimensions */
+                for(i = 0; i < space->extent.rank; i++) {
+                    tmp_start[i] = 0;
+                    tmp_stride[i] = 1;
+                    tmp_count[i] = 1;
+                    tmp_block[i] = space->extent.size[i];
+                } /* end for */
+
+                /* Convert to hyperslab selection */
+                if(H5S_select_hyperslab(space, H5S_SELECT_SET, tmp_start, tmp_stride, tmp_count, tmp_block) < 0)
+                    HGOTO_ERROR(H5E_DATASPACE, H5E_CANTSELECT, FAIL, "can't convert selection")
+            } /* end if */
+            else if(space->select.type->type == H5S_SEL_POINTS)
+                HDassert(0 && "Not yet implemented...");//VDSINC
+
+            HDassert(space->select.type->type == H5S_SEL_HYPERSLABS);
+            HDassert(subtract_space->select.type->type == H5S_SEL_HYPERSLABS);
+
+            /* Both spaces are now hyperslabs, perform the operation */
+            if(H5S__hyper_subtract(space, subtract_space) < 0)
+                HGOTO_ERROR(H5E_DATASPACE, H5E_CANTCLIP, FAIL, "can't subtract hyperslab")
+        } /* end else */
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5S_select_subtract() */
+
diff --git a/test/h5test.c b/test/h5test.c
index 88a8afa..848712c 100644
--- a/test/h5test.c
+++ b/test/h5test.c
@@ -122,9 +122,9 @@ h5_errors(hid_t estack, void UNUSED *client_data)
 
 
 /*-------------------------------------------------------------------------
- * Function:  h5_close_files
+ * Function:  h5_cleanup_files
  *
- * Purpose:  Cleanup temporary test files (always closes).
+ * Purpose:  Cleanup temporary test files (always).
  *    base_name contains the list of test file names.
  *
  * Return:  void
@@ -137,7 +137,7 @@ h5_errors(hid_t estack, void UNUSED *client_data)
  *-------------------------------------------------------------------------
  */
 void
-h5_close_files(const char *base_name[], hid_t fapl)
+h5_cleanup_files(const char *base_name[], hid_t fapl)
 {
     int i;
 
@@ -185,7 +185,7 @@ h5_close_files(const char *base_name[], hid_t fapl)
     } /* end for */
 
     return;
-} /* end h5_close_files() */
+} /* end h5_cleanup_files() */
 
 
 /*-------------------------------------------------------------------------
@@ -208,8 +208,8 @@ h5_cleanup(const char *base_name[], hid_t fapl)
     int    retval = 0;
 
     if(GetTestCleanup()) {
-        /* Close files in base_name */
-        h5_close_files(base_name, fapl);
+        /* Clean up files in base_name */
+        h5_cleanup_files(base_name, fapl);
 
         retval = 1;
     } /* end if */
diff --git a/test/h5test.h b/test/h5test.h
index e033322..46c73b6 100644
--- a/test/h5test.h
+++ b/test/h5test.h
@@ -142,7 +142,7 @@ extern "C" {
 
 /* Generally useful testing routines */
 H5TEST_DLL int h5_cleanup(const char *base_name[], hid_t fapl);
-H5TEST_DLL void h5_close_files(const char *base_name[], hid_t fapl);
+H5TEST_DLL void h5_cleanup_files(const char *base_name[], hid_t fapl);
 H5TEST_DLL char *h5_fixname(const char *base_name, hid_t fapl, char *fullname, size_t size);
 H5TEST_DLL char *h5_fixname_no_suffix(const char *base_name, hid_t fapl, char *fullname, size_t size);
 H5TEST_DLL hid_t h5_fileaccess(void);
diff --git a/test/vds.c b/test/vds.c
index 6d93e82..e6a57c2 100644
--- a/test/vds.c
+++ b/test/vds.c
@@ -1009,8 +1009,10 @@ test_basic_io(unsigned config, hid_t fapl)
     hsize_t     coord[10];      /* Point selection array */
     int         buf[10][26];    /* Write and expected read buffer */
     int         rbuf[10][26];   /* Read buffer */
+    int         rbuf99[9][9];   /* 9x9 Read buffer */
     int         evbuf[10][26];  /* Expected VDS "buffer" */
     int         erbuf[10][26];  /* Expected read buffer */
+    int         fill = -1;      /* Fill value */
     int         i, j;
 
     TESTING("basic virtual dataset I/O")
@@ -1022,6 +1024,10 @@ test_basic_io(unsigned config, hid_t fapl)
     if((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
         TEST_ERROR
 
+    /* Set fill value */
+    if(H5Pset_fill_value(dcpl, H5T_NATIVE_INT, &fill) < 0)
+        TEST_ERROR
+
     /*
      * Test 1: All - all selection
      */
@@ -2314,8 +2320,8 @@ test_basic_io(unsigned config, hid_t fapl)
     /* Select hyperslab in memory space */
     start[0] = 0;
     start[1] = 0;
-    count[0] = 3;
-    count[1] = 9;
+    count[0] = 9;
+    count[1] = 3;
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
         TEST_ERROR
 
@@ -2341,16 +2347,19 @@ test_basic_io(unsigned config, hid_t fapl)
 
     /* Update erbuf */
     HDmemset(erbuf, 0, sizeof(erbuf));
+    for(i = 0; i < 9; i++)
+        for(j = 0; j < 3; j++)
+            erbuf[i][j] = fill;
     erbuf[0][0] = buf[0][0];
     erbuf[0][2] = buf[0][1];
-    erbuf[0][6] = buf[0][8];
-    erbuf[0][8] = buf[0][9];
-    erbuf[2][0] = buf[1][0];
-    erbuf[2][2] = buf[1][1];
-    erbuf[2][6] = buf[1][8];
-    erbuf[2][8] = buf[1][9];
-    erbuf[1][3] = buf[0][13];
-    erbuf[1][5] = buf[0][14];
+    erbuf[2][0] = buf[0][8];
+    erbuf[2][2] = buf[0][9];
+    erbuf[6][0] = buf[1][0];
+    erbuf[6][2] = buf[1][1];
+    erbuf[8][0] = buf[1][8];
+    erbuf[8][2] = buf[1][9];
+    erbuf[4][0] = buf[0][13];
+    erbuf[4][2] = buf[0][14];
 
     /* Verify read data */
     for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
@@ -2373,30 +2382,45 @@ test_basic_io(unsigned config, hid_t fapl)
     if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
         TEST_ERROR
 
+    /* Select hyperslab in memory space */
+    start[0] = 0;
+    start[1] = 3;
+    count[0] = 9;
+    count[1] = 3;
+    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+
     /* Read second stripe pattern */
     if(H5Dread(vdset, H5T_NATIVE_INT, memspace, vspace[0], H5P_DEFAULT, rbuf[0]) < 0)
         TEST_ERROR
 
     /* Update erbuf */
-    HDmemset(erbuf, 0, sizeof(erbuf));
-    erbuf[0][3] = buf[0][4];
-    erbuf[0][5] = buf[0][5];
-    erbuf[1][0] = buf[0][6];
-    erbuf[1][1] = buf[0][7];
-    erbuf[1][2] = buf[0][12];
-    erbuf[1][3] = buf[0][15];
-    erbuf[1][5] = buf[1][4];
-    erbuf[1][6] = buf[1][7];
-    erbuf[1][7] = buf[1][12];
-    erbuf[1][8] = buf[1][13];
-    erbuf[2][3] = buf[1][14];
-    erbuf[2][5] = buf[1][15];
+    for(i = 0; i < 9; i++)
+        for(j = 3; j < 6; j++)
+            erbuf[i][j] = fill;
+    erbuf[1][3] = buf[0][4];
+    erbuf[1][5] = buf[0][5];
+    erbuf[3][3] = buf[0][6];
+    erbuf[3][4] = buf[0][7];
+    erbuf[3][5] = buf[0][12];
+    erbuf[4][3] = buf[0][15];
+    erbuf[4][5] = buf[1][4];
+    erbuf[5][3] = buf[1][7];
+    erbuf[5][4] = buf[1][12];
+    erbuf[5][5] = buf[1][13];
+    erbuf[7][3] = buf[1][14];
+    erbuf[7][5] = buf[1][15];
 
     /* Verify read data */
     for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
         for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+            if((j >= 3) && (j < 6)) {
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
 
     /* Reset rbuf */
     HDmemset(rbuf[0], 0, sizeof(rbuf));
@@ -2413,27 +2437,62 @@ test_basic_io(unsigned config, hid_t fapl)
     if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
         TEST_ERROR
 
+    /* Select hyperslab in memory space */
+    start[0] = 0;
+    start[1] = 6;
+    count[0] = 9;
+    count[1] = 3;
+    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+        TEST_ERROR
+
     /* Read third stripe pattern */
     if(H5Dread(vdset, H5T_NATIVE_INT, memspace, vspace[0], H5P_DEFAULT, rbuf[0]) < 0)
         TEST_ERROR
 
     /* Update erbuf */
-    HDmemset(erbuf, 0, sizeof(erbuf));
-    erbuf[0][0] = buf[0][2];
-    erbuf[0][2] = buf[0][3];
-    erbuf[0][6] = buf[0][10];
-    erbuf[0][8] = buf[0][11];
-    erbuf[2][0] = buf[1][2];
-    erbuf[2][2] = buf[1][3];
-    erbuf[2][6] = buf[1][10];
-    erbuf[2][8] = buf[1][11];
-    erbuf[1][3] = buf[1][5];
-    erbuf[1][5] = buf[1][6];
+    for(i = 0; i < 9; i++)
+        for(j = 6; j < 9; j++)
+            erbuf[i][j] = fill;
+    erbuf[0][6] = buf[0][2];
+    erbuf[0][8] = buf[0][3];
+    erbuf[2][6] = buf[0][10];
+    erbuf[2][8] = buf[0][11];
+    erbuf[6][6] = buf[1][2];
+    erbuf[6][8] = buf[1][3];
+    erbuf[8][6] = buf[1][10];
+    erbuf[8][8] = buf[1][11];
+    erbuf[4][6] = buf[1][5];
+    erbuf[4][8] = buf[1][6];
 
     /* Verify read data */
     for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
         for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
-            if(rbuf[i][j] != erbuf[i][j])
+            if((j >= 6) && (j < 9)) {
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+
+    /* Now read entire VDS */
+    /* Set memory space extent to 9x9, select all in order to reach  part of the
+     * code in H5S_select_subtract() */
+    dims[0] = 9;
+    dims[1] = 9;
+    if(H5Sset_extent_simple(memspace, 2, dims, NULL) < 0)
+        TEST_ERROR
+    if(H5Sselect_all(memspace) < 0)
+        TEST_ERROR
+
+    /* Read third stripe pattern */
+    if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf99[0]) < 0)
+        TEST_ERROR
+
+    /* Verify read data */
+    for(i = 0; i < (int)(sizeof(rbuf99) / sizeof(rbuf99[0])); i++)
+        for(j = 0; j < (int)(sizeof(rbuf99[0]) / sizeof(rbuf99[0][0])); j++)
+            if(rbuf99[i][j] != erbuf[i][j])
                 TEST_ERROR
 
     /* Adjust write buffer */
@@ -2442,16 +2501,46 @@ test_basic_io(unsigned config, hid_t fapl)
             buf[i][j] += (int)(sizeof(buf) / sizeof(buf[0][0]));
 
     /* Write data through virtual dataset by hyperslab */
-    /* Select stripe */
+    /* Select stripe (only select mapped elements) */
     start[0] = 0;
     start[1] = 0;
     start[2] = 0;
     start[3] = 0;
-    count[0] = 3;
-    count[1] = 3;
+    stride[0] = 2;
+    stride[1] = 2;
+    stride[2] = 1;
+    stride[3] = 2;
+    count[0] = 2;
+    count[1] = 2;
     count[2] = 1;
-    count[3] = 3;
-    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+    count[3] = 2;
+    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, stride ,count, NULL) < 0)
+        TEST_ERROR
+    start[0] = 1;
+    start[1] = 1;
+    start[2] = 0;
+    start[3] = 0;
+    stride[0] = 1;
+    stride[1] = 1;
+    stride[2] = 1;
+    stride[3] = 2;
+    count[0] = 1;
+    count[1] = 1;
+    count[2] = 1;
+    count[3] = 2;
+    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_OR, start, stride ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Reset extent of memspace, select hyperslab */
+    dims[0] = 10;
+    dims[1] = 26;
+    if(H5Sset_extent_simple(memspace, 2, dims, NULL) < 0)
+        TEST_ERROR
+    start[0] = 0;
+    start[1] = 0;
+    count[0] = 1;
+    count[1] = 10;
+    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
         TEST_ERROR
 
     /* Write data through virtual dataset by hyperslab */
@@ -2462,31 +2551,57 @@ test_basic_io(unsigned config, hid_t fapl)
     /* Update erbuf */
     HDmemset(erbuf, 0, sizeof(erbuf));
     erbuf[0][0] = buf[0][0];
-    erbuf[0][1] = buf[0][2];
-    erbuf[0][8] = buf[0][6];
-    erbuf[0][9] = buf[0][8];
-    erbuf[1][0] = buf[2][0];
-    erbuf[1][1] = buf[2][2];
-    erbuf[1][8] = buf[2][6];
-    erbuf[1][9] = buf[2][8];
-    erbuf[0][13] = buf[1][3];
-    erbuf[0][14] = buf[1][5];
+    erbuf[0][1] = buf[0][1];
+    erbuf[0][8] = buf[0][2];
+    erbuf[0][9] = buf[0][3];
+    erbuf[1][0] = buf[0][6];
+    erbuf[1][1] = buf[0][7];
+    erbuf[1][8] = buf[0][8];
+    erbuf[1][9] = buf[0][9];
+    erbuf[0][13] = buf[0][4];
+    erbuf[0][14] = buf[0][5];
 
     /* Adjust write buffer */
     for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
         for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
             buf[i][j] += (int)(sizeof(buf) / sizeof(buf[0][0]));
 
-    /* Select stripe */
+    /* Select stripe (only select mapped elements) */
     start[0] = 0;
-    start[1] = 0;
+    start[1] = 1;
     start[2] = 1;
     start[3] = 0;
+    stride[0] = 1;
+    stride[1] = 1;
+    stride[2] = 1;
+    stride[3] = 2;
     count[0] = 3;
-    count[1] = 3;
+    count[1] = 1;
+    count[2] = 1;
+    count[3] = 2;
+    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, stride ,count, NULL) < 0)
+        TEST_ERROR
+    start[0] = 1;
+    start[1] = 0;
+    start[2] = 1;
+    start[3] = 0;
+    stride[0] = 1;
+    stride[1] = 2;
+    stride[2] = 1;
+    stride[3] = 1;
+    count[0] = 1;
+    count[1] = 2;
     count[2] = 1;
     count[3] = 3;
-    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_OR, start, stride ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Select hyperslab in memory space */
+    start[0] = 0;
+    start[1] = 0;
+    count[0] = 1;
+    count[1] = 12;
+    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
         TEST_ERROR
 
     /* Write second slice */
@@ -2494,34 +2609,60 @@ test_basic_io(unsigned config, hid_t fapl)
         TEST_ERROR
 
     /* Update erbuf */
-    erbuf[0][4] = buf[0][3];
-    erbuf[0][5] = buf[0][5];
-    erbuf[0][6] = buf[1][0];
-    erbuf[0][7] = buf[1][1];
-    erbuf[0][12] = buf[1][2];
-    erbuf[0][15] = buf[1][3];
-    erbuf[1][4] = buf[1][5];
-    erbuf[1][7] = buf[1][6];
-    erbuf[1][12] = buf[1][7];
-    erbuf[1][13] = buf[1][8];
-    erbuf[1][14] = buf[2][3];
-    erbuf[1][15] = buf[2][5];
+    erbuf[0][4] = buf[0][0];
+    erbuf[0][5] = buf[0][1];
+    erbuf[0][6] = buf[0][2];
+    erbuf[0][7] = buf[0][3];
+    erbuf[0][12] = buf[0][4];
+    erbuf[0][15] = buf[0][5];
+    erbuf[1][4] = buf[0][6];
+    erbuf[1][7] = buf[0][7];
+    erbuf[1][12] = buf[0][8];
+    erbuf[1][13] = buf[0][9];
+    erbuf[1][14] = buf[0][10];
+    erbuf[1][15] = buf[0][11];
 
     /* Adjust write buffer */
     for(i = 0; i < (int)(sizeof(buf) / sizeof(buf[0])); i++)
         for(j = 0; j < (int)(sizeof(buf[0]) / sizeof(buf[0][0])); j++)
             buf[i][j] += (int)(sizeof(buf) / sizeof(buf[0][0]));
 
-    /* Select stripe */
+    /* Select stripe (only select mapped elements) */
     start[0] = 0;
     start[1] = 0;
     start[2] = 2;
     start[3] = 0;
-    count[0] = 3;
-    count[1] = 3;
+    stride[0] = 2;
+    stride[1] = 2;
+    stride[2] = 1;
+    stride[3] = 2;
+    count[0] = 2;
+    count[1] = 2;
     count[2] = 1;
-    count[3] = 3;
-    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
+    count[3] = 2;
+    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, stride ,count, NULL) < 0)
+        TEST_ERROR
+    start[0] = 1;
+    start[1] = 1;
+    start[2] = 2;
+    start[3] = 0;
+    stride[0] = 1;
+    stride[1] = 1;
+    stride[2] = 1;
+    stride[3] = 2;
+    count[0] = 1;
+    count[1] = 1;
+    count[2] = 1;
+    count[3] = 2;
+    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_OR, start, stride ,count, NULL) < 0)
+        TEST_ERROR
+
+    /* Select hyperslab in memory space */
+    start[0] = 0;
+    start[1] = 0;
+    count[0] = 1;
+    count[1] = 10;
+    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL ,count, NULL) < 0)
         TEST_ERROR
 
     /* Write third slice */
@@ -2530,15 +2671,15 @@ test_basic_io(unsigned config, hid_t fapl)
 
     /* Update erbuf */
     erbuf[0][2] = buf[0][0];
-    erbuf[0][3] = buf[0][2];
-    erbuf[0][10] = buf[0][6];
-    erbuf[0][11] = buf[0][8];
-    erbuf[1][2] = buf[2][0];
-    erbuf[1][3] = buf[2][2];
-    erbuf[1][10] = buf[2][6];
-    erbuf[1][11] = buf[2][8];
-    erbuf[1][5] = buf[1][3];
-    erbuf[1][6] = buf[1][5];
+    erbuf[0][3] = buf[0][1];
+    erbuf[0][10] = buf[0][2];
+    erbuf[0][11] = buf[0][3];
+    erbuf[1][2] = buf[0][6];
+    erbuf[1][3] = buf[0][7];
+    erbuf[1][10] = buf[0][8];
+    erbuf[1][11] = buf[0][9];
+    erbuf[1][5] = buf[0][4];
+    erbuf[1][6] = buf[0][5];
 
     /* Reopen srcdset and srcfile if config option specified */
     if(config & TEST_IO_CLOSE_SRC) {
@@ -2684,6 +2825,7 @@ test_unlim(unsigned config, hid_t fapl)
     int         rbuf[10][20];   /* Read buffer */
     int         erbuf[10][20];  /* Expected read buffer */
     int         ndims;          /* Number of dimensions */
+    int         fill = -1;      /* Fill value */
     int         i, j;
 
     TESTING("virtual dataset I/O with unlimited selections")
@@ -2697,14 +2839,18 @@ test_unlim(unsigned config, hid_t fapl)
     if((srcdcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
         TEST_ERROR
 
-    /* Create DAPL */
-    if((dapl = H5Pcreate(H5P_DATASET_ACCESS)) < 0)
+    /* Set fill value */
+    if(H5Pset_fill_value(dcpl, H5T_NATIVE_INT, &fill) < 0)
         TEST_ERROR
 
     /* Set chunk dimensions */
     if(H5Pset_chunk(srcdcpl, 2, cdims) < 0)
         TEST_ERROR
 
+    /* Create DAPL */
+    if((dapl = H5Pcreate(H5P_DATASET_ACCESS)) < 0)
+        TEST_ERROR
+
     /* Create memory space */
     if((memspace = H5Screate_simple(2, mdims, NULL)) < 0)
         TEST_ERROR
@@ -2784,7 +2930,7 @@ test_unlim(unsigned config, hid_t fapl)
     /* Initialize erbuf */
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++)
-            erbuf[i][j] = -1;
+            erbuf[i][j] = fill;
 
     /* Write data directly to source datasets */
     /* Select hyperslab in memory */
@@ -2872,12 +3018,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     start[0] = 0;
@@ -2890,9 +3031,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_FIRST_MISSING, reopen file
      * as well if config option specified */
@@ -2936,12 +3083,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Read data */
     if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
@@ -2949,9 +3091,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Reopen srcdset[0] and srcfile if config option specified */
     if(config & TEST_IO_CLOSE_SRC) {
@@ -3040,12 +3188,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     start[1] = 0;
@@ -3058,9 +3201,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_LAST_AVAILABLE, reopen file
      * as well if config option specified */
@@ -3110,12 +3259,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     start[1] = 0;
@@ -3128,9 +3272,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Reopen srcdset[1] and srcfile if config option specified */
     if(config & TEST_IO_CLOSE_SRC) {
@@ -3222,12 +3372,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     start[1] = 0;
@@ -3245,9 +3390,7 @@ test_unlim(unsigned config, hid_t fapl)
                 TEST_ERROR
 
     /* Now just read middle 2 rows */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
     start[0] = 4;
     count[0] = 2;
     count[1] = 20;
@@ -3265,7 +3408,7 @@ test_unlim(unsigned config, hid_t fapl)
                     TEST_ERROR
             } /* end if */
             else
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
 
     /* Close VDS and reopen with view set to H5D_VDS_FIRST_MISSING, reopen file
@@ -3288,7 +3431,7 @@ test_unlim(unsigned config, hid_t fapl)
      * change to H5D_VDS_FIRST_MISSING */
     for(i = 5; i < 10; i++)
         for(j = 15; j < 20; j++)
-            erbuf[i][j] = -1;
+            erbuf[i][j] = fill;
 
     /* Get VDS space */
     if((filespace = H5Dget_space(vdset)) < 0)
@@ -3316,12 +3459,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     start[0] = 0;
@@ -3335,9 +3473,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close */
     if(!(config & TEST_IO_CLOSE_SRC)) {
@@ -3456,7 +3600,7 @@ test_unlim(unsigned config, hid_t fapl)
     /* Initialize erbuf */
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++)
-            erbuf[i][j] = -1;
+            erbuf[i][j] = fill;
 
     /* Write data directly to source datasets */
     /* Select hyperslab in memory */
@@ -3544,12 +3688,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -3561,9 +3700,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_FIRST_MISSING, reopen file
      * as well if config option specified */
@@ -3607,12 +3752,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Read data */
     if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
@@ -3620,9 +3760,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Reopen srcdset[0] and srcfile if config option specified */
     if(config & TEST_IO_CLOSE_SRC) {
@@ -3716,12 +3862,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -3733,9 +3874,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_LAST_AVAILABLE, reopen file
      * as well if config option specified */
@@ -3784,12 +3931,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -3801,9 +3943,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Reopen srcdset[1] and srcfile if config option specified */
     if(config & TEST_IO_CLOSE_SRC) {
@@ -3895,12 +4043,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -3917,9 +4060,7 @@ test_unlim(unsigned config, hid_t fapl)
                 TEST_ERROR
 
     /* Now just read middle 2 rows */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
     start[0] = 4;
     count[0] = 2;
     count[1] = 20;
@@ -3938,7 +4079,7 @@ test_unlim(unsigned config, hid_t fapl)
                     TEST_ERROR
             } /* end if */
             else
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
 
     /* Close VDS and reopen with view set to H5D_VDS_FIRST_MISSING, reopen file
@@ -3961,7 +4102,7 @@ test_unlim(unsigned config, hid_t fapl)
      * change to H5D_VDS_FIRST_MISSING */
     for(i = 0; i < 10; i++)
         for(j = 15; j < 20; j += 2)
-            erbuf[i][j] = -1;
+            erbuf[i][j] = fill;
 
     /* Get VDS space */
     if((filespace = H5Dget_space(vdset)) < 0)
@@ -3989,12 +4130,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -4006,9 +4142,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close */
     if(!(config & TEST_IO_CLOSE_SRC)) {
@@ -4148,7 +4290,7 @@ test_unlim(unsigned config, hid_t fapl)
     /* Initialize erbuf */
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++)
-            erbuf[i][j] = -1;
+            erbuf[i][j] = fill;
 
     /* Write data directly to source datasets */
     /* Select hyperslab in memory */
@@ -4264,12 +4406,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -4281,9 +4418,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_FIRST_MISSING, reopen file
      * as well if config option specified */
@@ -4327,12 +4470,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Read data */
     if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
@@ -4340,9 +4478,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Reopen srcdset[0] and srcfile if config option specified */
     if(config & TEST_IO_CLOSE_SRC) {
@@ -4430,12 +4574,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -4447,9 +4586,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_LAST_AVAILABLE, reopen file
      * as well if config option specified */
@@ -4501,12 +4646,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -4518,9 +4658,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Reopen srcdset[2] and srcfile if config option specified */
     if(config & TEST_IO_CLOSE_SRC) {
@@ -4615,12 +4761,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -4632,9 +4773,15 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_FIRST_MISSING, reopen file
      * as well if config option specified */
@@ -4678,12 +4825,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -4693,17 +4835,17 @@ test_unlim(unsigned config, hid_t fapl)
     if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
         TEST_ERROR
 
-    /* Verify read data - algorithmically check for no data past the extent so
-     * we don't have to wipe out erbuf and then restore it afterwards */
+    /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(j < 14) {
-                if(rbuf[i][j] != erbuf[i][j])
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != erbuf[i][j])
                     TEST_ERROR
+        } /* end for */
 
     /* Reopen srcdset[1] and srcfile if config option specified */
     if(config & TEST_IO_CLOSE_SRC) {
@@ -4796,12 +4938,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -4811,17 +4948,17 @@ test_unlim(unsigned config, hid_t fapl)
     if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
         TEST_ERROR
 
-    /* Verify read data - algorithmically check for no data past the extent so
-     * we don't have to wipe out erbuf and then restore it afterwards */
+    /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(j < 17) {
-                if(rbuf[i][j] != erbuf[i][j])
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != erbuf[i][j])
                     TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_LAST_AVAILABLE, reopen file
      * as well if config option specified */
@@ -4861,12 +4998,7 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -4878,14 +5010,18 @@ test_unlim(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Now just read middle 2 rows */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
     start[0] = 4;
     count[0] = 2;
     count[1] = 19;
@@ -4905,12 +5041,16 @@ test_unlim(unsigned config, hid_t fapl)
      * read */
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++)
-            if((i == 4) || (i == 5)) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else if((i == 4) || (i == 5)) {
                 if(rbuf[i][j] != erbuf[i][j])
                     TEST_ERROR
             } /* end if */
             else
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
 
     /* Close */
@@ -5056,6 +5196,7 @@ test_printf(unsigned config, hid_t fapl)
     int         rbuf[10][20];   /* Read buffer */
     int         erbuf[10][20];  /* Expected read buffer */
     int         ndims;          /* Number of dimensions */
+    int         fill = -1;      /* Fill value */
     int         i, j;
 
     TESTING("virtual dataset I/O with printf source")
@@ -5069,6 +5210,10 @@ test_printf(unsigned config, hid_t fapl)
     if((dcpl = H5Pcreate(H5P_DATASET_CREATE)) < 0)
         TEST_ERROR
 
+    /* Set fill value */
+    if(H5Pset_fill_value(dcpl, H5T_NATIVE_INT, &fill) < 0)
+        TEST_ERROR
+
     /* Create DAPL */
     if((dapl = H5Pcreate(H5P_DATASET_ACCESS)) < 0)
         TEST_ERROR
@@ -5193,7 +5338,7 @@ test_printf(unsigned config, hid_t fapl)
     /* Initialize erbuf */
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++)
-            erbuf[i][j] = -1;
+            erbuf[i][j] = fill;
 
     /* Write to srcdset[0] */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
@@ -5276,12 +5421,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -5293,9 +5433,15 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Reopen srcfile if config option specified */
     if((config & TEST_IO_CLOSE_SRC) && (config & TEST_IO_DIFFERENT_FILE))
@@ -5375,12 +5521,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -5392,9 +5533,15 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close */
     if(!(config & TEST_IO_CLOSE_SRC)) {
@@ -5554,7 +5701,7 @@ test_printf(unsigned config, hid_t fapl)
     /* Initialize erbuf */
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++)
-            erbuf[i][j] = -1;
+            erbuf[i][j] = fill;
 
     /* Write to srcdset[0] */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
@@ -5686,12 +5833,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -5705,7 +5847,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -5755,12 +5897,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -5774,7 +5911,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -5824,12 +5961,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -5843,7 +5975,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -5893,12 +6025,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -5912,7 +6039,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -5962,12 +6089,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -5981,7 +6103,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -6031,12 +6153,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -6050,7 +6167,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -6094,619 +6211,628 @@ test_printf(unsigned config, hid_t fapl)
     vspace[0] = -1;
 
 
-    /*
-     * Test 3: 1 Source dataset mapping, 10x5 blocks, printf source file
-     */
-    /* Clean up files so the source files do not exist yet */
-    h5_close_files(FILENAME, fapl);
+    /* Next 2 tests are always run with a different source file, so only run if
+     * that config option is set (so they're not run twice with the same
+     * configuration) */
+    if(config & TEST_IO_DIFFERENT_FILE) {
+        /*
+         * Test 3: 1 Source dataset mapping, 10x5 blocks, printf source file
+         */
+        /* Clean up files so the source files do not exist yet */
+        h5_cleanup_files(FILENAME, fapl);
 
-    /* Clear virtual layout in DCPL */
-    if(H5Pset_layout(dcpl, H5D_VIRTUAL) < 0)
-        TEST_ERROR
+        /* Clear virtual layout in DCPL */
+        if(H5Pset_layout(dcpl, H5D_VIRTUAL) < 0)
+            TEST_ERROR
 
-    /* Create virtual dataspaces */
-    if((vspace[0] = H5Screate_simple(2, dims, mdims)) < 0)
-        TEST_ERROR
+        /* Create virtual dataspaces */
+        if((vspace[0] = H5Screate_simple(2, dims, mdims)) < 0)
+            TEST_ERROR
 
-    /* Create source dataspace */
-    dims[1] = 5;
-    if((srcspace = H5Screate_simple(2, dims, NULL)) < 0)
-        TEST_ERROR
+        /* Create source dataspace */
+        dims[1] = 5;
+        if((srcspace = H5Screate_simple(2, dims, NULL)) < 0)
+            TEST_ERROR
 
-    /* Select hyperslabs in virtual space */
-    stride[0] = 1;
-    stride[1] = 5;
-    count[0] = 1;
-    count[1] = H5S_UNLIMITED;
-    block[0] = 10;
-    block[1] = 5;
-    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, stride, count, block) < 0)
-        TEST_ERROR
+        /* Select hyperslabs in virtual space */
+        stride[0] = 1;
+        stride[1] = 5;
+        count[0] = 1;
+        count[1] = H5S_UNLIMITED;
+        block[0] = 10;
+        block[1] = 5;
+        if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, stride, count, block) < 0)
+            TEST_ERROR
 
-    /* Add virtual layout mapping */
-    if(H5Pset_virtual(dcpl, vspace[0], printf_srcfilename, "src_dset", srcspace) < 0)
-        TEST_ERROR
+        /* Add virtual layout mapping */
+        if(H5Pset_virtual(dcpl, vspace[0], printf_srcfilename, "src_dset", srcspace) < 0)
+            TEST_ERROR
 
-    /* Create virtual file */
-    if((vfile = H5Fcreate(vfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
-        TEST_ERROR
+        /* Create virtual file */
+        if((vfile = H5Fcreate(vfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
 
-    /* Create virtual dataset */
-    if((vdset = H5Dcreate2(vfile, "v_dset", H5T_NATIVE_INT, vspace[0], H5P_DEFAULT, dcpl, dapl)) < 0)
-        TEST_ERROR
+        /* Create virtual dataset */
+        if((vdset = H5Dcreate2(vfile, "v_dset", H5T_NATIVE_INT, vspace[0], H5P_DEFAULT, dcpl, dapl)) < 0)
+            TEST_ERROR
 
-    /* Reopen virtual dataset and file if config option specified */
-    if(config & TEST_IO_REOPEN_VIRT) {
-        if(H5Dclose(vdset) < 0)
+        /* Reopen virtual dataset and file if config option specified */
+        if(config & TEST_IO_REOPEN_VIRT) {
+            if(H5Dclose(vdset) < 0)
+                TEST_ERROR
+            vdset = -1;
+            if(H5Fclose(vfile) < 0)
+                TEST_ERROR
+            vfile = -1;
+            if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+                TEST_ERROR
+            if((vdset = H5Dopen2(vfile, "v_dset", H5P_DEFAULT)) < 0)
+                TEST_ERROR
+        } /* end if */
+
+        /* Get VDS space */
+        if((filespace = H5Dget_space(vdset)) < 0)
             TEST_ERROR
-        vdset = -1;
-        if(H5Fclose(vfile) < 0)
+
+        /* Get VDS space dimensions */
+        if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
             TEST_ERROR
-        vfile = -1;
-        if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+        if(ndims != 2)
             TEST_ERROR
-        if((vdset = H5Dopen2(vfile, "v_dset", H5P_DEFAULT)) < 0)
+        if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
+            TEST_ERROR
+        if(dims[0] != 10)
+            TEST_ERROR
+        if(dims[1] != 0)
+            TEST_ERROR
+        if(mdims[0] != 10)
+            TEST_ERROR
+        if(mdims[1] != 20)
             TEST_ERROR
-    } /* end if */
 
-    /* Get VDS space */
-    if((filespace = H5Dget_space(vdset)) < 0)
-        TEST_ERROR
+        /* Close filespace */
+        if(H5Sclose(filespace) < 0)
+            TEST_ERROR
 
-    /* Get VDS space dimensions */
-    if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
-        TEST_ERROR
-    if(ndims != 2)
-        TEST_ERROR
-    if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
-        TEST_ERROR
-    if(dims[0] != 10)
-        TEST_ERROR
-    if(dims[1] != 0)
-        TEST_ERROR
-    if(mdims[0] != 10)
-        TEST_ERROR
-    if(mdims[1] != 20)
-        TEST_ERROR
+        /* Create 2 source files, one source dataset */
+        if((srcfile[0] = H5Fcreate(srcfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
+        if((srcdset[0] = H5Dcreate2(srcfile[0], "src_dset", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+            TEST_ERROR
+        if((srcfile[1] = H5Fcreate(srcfilename2, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
 
-    /* Close filespace */
-    if(H5Sclose(filespace) < 0)
-        TEST_ERROR
+        /* Populate write buffer */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++)
+                buf[i][j] = (i * (int)mdims[1]) + j;
 
-    /* Create 2 source files, one source dataset */
-    if((srcfile[0] = H5Fcreate(srcfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
-        TEST_ERROR
-    if((srcdset[0] = H5Dcreate2(srcfile[0], "src_dset", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
-        TEST_ERROR
-    if((srcfile[1] = H5Fcreate(srcfilename2, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
-        TEST_ERROR
+        /* Initialize erbuf */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++)
+                erbuf[i][j] = fill;
 
-    /* Populate write buffer */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            buf[i][j] = (i * (int)mdims[1]) + j;
+        /* Write to srcdset[0] */
+        if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
+            TEST_ERROR
+        if(H5Dwrite(srcdset[0], H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
+            TEST_ERROR
 
-    /* Initialize erbuf */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            erbuf[i][j] = -1;
+        /* Update erbuf */
+        for(i = 0; i < 10; i++)
+            for(j = 0; j < 5; j++)
+                erbuf[i][j] = buf[i][j];
 
-    /* Write to srcdset[0] */
-    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
-        TEST_ERROR
-    if(H5Dwrite(srcdset[0], H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
-        TEST_ERROR
+        /* Close srcdset and srcfiles if config option specified */
+        if(config & TEST_IO_CLOSE_SRC) {
+            if(H5Dclose(srcdset[0]) < 0)
+                TEST_ERROR
+            srcdset[0] = -1;
+            if(H5Fclose(srcfile[0]) < 0)
+                TEST_ERROR
+            srcfile[0] = -1;
+            if(H5Fclose(srcfile[1]) < 0)
+                TEST_ERROR
+            srcfile[1] = -1;
+        } /* end if */
 
-    /* Update erbuf */
-    for(i = 0; i < 10; i++)
-        for(j = 0; j < 5; j++)
-            erbuf[i][j] = buf[i][j];
+        /* Reopen virtual dataset and file if config option specified */
+        if(config & TEST_IO_REOPEN_VIRT) {
+            if(H5Dclose(vdset) < 0)
+                TEST_ERROR
+            vdset = -1;
+            if(H5Fclose(vfile) < 0)
+                TEST_ERROR
+            vfile = -1;
+            if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+                TEST_ERROR
+            if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+                TEST_ERROR
+        } /* end if */
 
-    /* Close srcdset and srcfiles if config option specified */
-    if(config & TEST_IO_CLOSE_SRC) {
-        if(H5Dclose(srcdset[0]) < 0)
+        /* Get VDS space */
+        if((filespace = H5Dget_space(vdset)) < 0)
             TEST_ERROR
-        srcdset[0] = -1;
-        if(H5Fclose(srcfile[0]) < 0)
+
+        /* Get VDS space dimensions */
+        if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
             TEST_ERROR
-        srcfile[0] = -1;
-        if(H5Fclose(srcfile[1]) < 0)
+        if(ndims != 2)
             TEST_ERROR
-        srcfile[1] = -1;
-    } /* end if */
-
-    /* Reopen virtual dataset and file if config option specified */
-    if(config & TEST_IO_REOPEN_VIRT) {
-        if(H5Dclose(vdset) < 0)
+        if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
             TEST_ERROR
-        vdset = -1;
-        if(H5Fclose(vfile) < 0)
+        if(dims[0] != 10)
             TEST_ERROR
-        vfile = -1;
-        if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+        if(dims[1] != 5)
             TEST_ERROR
-        if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+        if(mdims[0] != 10)
+            TEST_ERROR
+        if(mdims[1] != 20)
             TEST_ERROR
-    } /* end if */
-
-    /* Get VDS space */
-    if((filespace = H5Dget_space(vdset)) < 0)
-        TEST_ERROR
 
-    /* Get VDS space dimensions */
-    if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
-        TEST_ERROR
-    if(ndims != 2)
-        TEST_ERROR
-    if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
-        TEST_ERROR
-    if(dims[0] != 10)
-        TEST_ERROR
-    if(dims[1] != 5)
-        TEST_ERROR
-    if(mdims[0] != 10)
-        TEST_ERROR
-    if(mdims[1] != 20)
-        TEST_ERROR
+        /* Close filespace */
+        if(H5Sclose(filespace) < 0)
+            TEST_ERROR
 
-    /* Close filespace */
-    if(H5Sclose(filespace) < 0)
-        TEST_ERROR
+        /* Read data through virtual dataset */
+        /* Reset rbuf */
+        HDmemset(rbuf[0], 0, sizeof(rbuf));
 
-    /* Read data through virtual dataset */
-    /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+        /* Select hyperslab in memory space */
+        if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
+            TEST_ERROR
 
-    /* Select hyperslab in memory space */
-    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
-        TEST_ERROR
+        /* Read data */
+        if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
+            TEST_ERROR
 
-    /* Read data */
-    if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
-        TEST_ERROR
+        /* Verify read data */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++) {
+                if(j >= (int)dims[1]) {
+                    if(rbuf[i][j] != 0)
+                        TEST_ERROR
+                } /* end if */
+                else
+                    if(rbuf[i][j] != erbuf[i][j])
+                        TEST_ERROR
+            } /* end for */
 
-    /* Verify read data */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
+        /* Reopen srcfile[1] if config option specified */
+        if(config & TEST_IO_CLOSE_SRC)
+            if((srcfile[1] = H5Fopen(srcfilename2, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
                 TEST_ERROR
 
-    /* Reopen srcfile[1] if config option specified */
-    if(config & TEST_IO_CLOSE_SRC)
-        if((srcfile[1] = H5Fopen(srcfilename2, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+        /* Create 2nd source dataset */
+        if((srcdset[1] = H5Dcreate2(srcfile[1], "src_dset", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR
 
-    /* Create 2nd source dataset */
-    if((srcdset[1] = H5Dcreate2(srcfile[1], "src_dset", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
-        TEST_ERROR
+        /* Adjust write buffer */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++)
+                buf[i][j] += (int)mdims[0] * (int)mdims[1];
 
-    /* Adjust write buffer */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            buf[i][j] += (int)mdims[0] * (int)mdims[1];
+        /* Write to srcdset[1] */
+        if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
+            TEST_ERROR
+        if(H5Dwrite(srcdset[1], H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
+            TEST_ERROR
 
-    /* Write to srcdset[1] */
-    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
-        TEST_ERROR
-    if(H5Dwrite(srcdset[1], H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
-        TEST_ERROR
+        /* Update erbuf */
+        for(i = 0; i < 10; i++)
+            for(j = 0; j < 5; j++)
+                erbuf[i][j + 5] = buf[i][j];
 
-    /* Update erbuf */
-    for(i = 0; i < 10; i++)
-        for(j = 0; j < 5; j++)
-            erbuf[i][j + 5] = buf[i][j];
+        /* Close srcdset[1] and srcfile[1] if config option specified */
+        if(config & TEST_IO_CLOSE_SRC) {
+            if(H5Dclose(srcdset[1]) < 0)
+                TEST_ERROR
+            srcdset[1] = -1;
+            if(H5Fclose(srcfile[1]) < 0)
+                TEST_ERROR
+            srcfile[1] = -1;
+        } /* end if */
 
-    /* Close srcdset[1] and srcfile[1] if config option specified */
-    if(config & TEST_IO_CLOSE_SRC) {
-        if(H5Dclose(srcdset[1]) < 0)
-            TEST_ERROR
-        srcdset[1] = -1;
-        if(H5Fclose(srcfile[1]) < 0)
+        /* Reopen virtual dataset and file if config option specified */
+        if(config & TEST_IO_REOPEN_VIRT) {
+            if(H5Dclose(vdset) < 0)
+                TEST_ERROR
+            vdset = -1;
+            if(H5Fclose(vfile) < 0)
+                TEST_ERROR
+            vfile = -1;
+            if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+                TEST_ERROR
+            if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+                TEST_ERROR
+        } /* end if */
+
+        /* Get VDS space */
+        if((filespace = H5Dget_space(vdset)) < 0)
             TEST_ERROR
-        srcfile[1] = -1;
-    } /* end if */
 
-    /* Reopen virtual dataset and file if config option specified */
-    if(config & TEST_IO_REOPEN_VIRT) {
-        if(H5Dclose(vdset) < 0)
+        /* Get VDS space dimensions */
+        if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
             TEST_ERROR
-        vdset = -1;
-        if(H5Fclose(vfile) < 0)
+        if(ndims != 2)
             TEST_ERROR
-        vfile = -1;
-        if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+        if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
             TEST_ERROR
-        if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+        if(dims[0] != 10)
+            TEST_ERROR
+        if(dims[1] != 10)
+            TEST_ERROR
+        if(mdims[0] != 10)
+            TEST_ERROR
+        if(mdims[1] != 20)
             TEST_ERROR
-    } /* end if */
-
-    /* Get VDS space */
-    if((filespace = H5Dget_space(vdset)) < 0)
-        TEST_ERROR
 
-    /* Get VDS space dimensions */
-    if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
-        TEST_ERROR
-    if(ndims != 2)
-        TEST_ERROR
-    if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
-        TEST_ERROR
-    if(dims[0] != 10)
-        TEST_ERROR
-    if(dims[1] != 10)
-        TEST_ERROR
-    if(mdims[0] != 10)
-        TEST_ERROR
-    if(mdims[1] != 20)
-        TEST_ERROR
+        /* Close filespace */
+        if(H5Sclose(filespace) < 0)
+            TEST_ERROR
 
-    /* Close filespace */
-    if(H5Sclose(filespace) < 0)
-        TEST_ERROR
+        /* Read data through virtual dataset */
+        /* Reset rbuf */
+        HDmemset(rbuf[0], 0, sizeof(rbuf));
 
-    /* Read data through virtual dataset */
-    /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+        /* Select hyperslab in memory space */
+        if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
+            TEST_ERROR
 
-    /* Select hyperslab in memory space */
-    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
-        TEST_ERROR
+        /* Read data */
+        if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
+            TEST_ERROR
 
-    /* Read data */
-    if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
-        TEST_ERROR
+        /* Verify read data */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++) {
+                if(j >= (int)dims[1]) {
+                    if(rbuf[i][j] != 0)
+                        TEST_ERROR
+                } /* end if */
+                else
+                    if(rbuf[i][j] != erbuf[i][j])
+                        TEST_ERROR
+            } /* end for */
 
-    /* Verify read data */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
+        /* Close */
+        if(!(config & TEST_IO_CLOSE_SRC)) {
+            if(H5Dclose(srcdset[0]) < 0)
                 TEST_ERROR
-
-    /* Close */
-    if(!(config & TEST_IO_CLOSE_SRC)) {
-        if(H5Dclose(srcdset[0]) < 0)
+            srcdset[0] = -1;
+            if(H5Dclose(srcdset[1]) < 0)
+                TEST_ERROR
+            srcdset[1] = -1;
+            if(H5Fclose(srcfile[0]) < 0)
+                TEST_ERROR
+            srcfile[0] = -1;
+            if(H5Fclose(srcfile[1]) < 0)
+                TEST_ERROR
+            srcfile[1] = -1;
+        } /* end if */
+        if(H5Dclose(vdset) < 0)
             TEST_ERROR
-        srcdset[0] = -1;
-        if(H5Dclose(srcdset[1]) < 0)
+        vdset = -1;
+        if(H5Fclose(vfile) < 0)
             TEST_ERROR
-        srcdset[1] = -1;
-        if(H5Fclose(srcfile[0]) < 0)
+        vfile = -1;
+        if(H5Sclose(srcspace) < 0)
             TEST_ERROR
-        srcfile[0] = -1;
-        if(H5Fclose(srcfile[1]) < 0)
+        srcspace = -1;
+        if(H5Sclose(vspace[0]) < 0)
             TEST_ERROR
-        srcfile[1] = -1;
-    } /* end if */
-    if(H5Dclose(vdset) < 0)
-        TEST_ERROR
-    vdset = -1;
-    if(H5Fclose(vfile) < 0)
-        TEST_ERROR
-    vfile = -1;
-    if(H5Sclose(srcspace) < 0)
-        TEST_ERROR
-    srcspace = -1;
-    if(H5Sclose(vspace[0]) < 0)
-        TEST_ERROR
-    vspace[0] = -1;
+        vspace[0] = -1;
 
 
-    /*
-     * Test 4: 1 Source dataset mapping, 10x5 blocks, printf source file and
-     * source dset, extra %%s in source dataset name
-     */
-    /* Clean up files so the source files do not exist yet */
-    h5_close_files(FILENAME, fapl);
+        /*
+         * Test 4: 1 Source dataset mapping, 10x5 blocks, printf source file and
+         * source dset, extra %%s in source dataset name
+         */
+        /* Clean up files so the source files do not exist yet */
+        h5_cleanup_files(FILENAME, fapl);
 
-    /* Clear virtual layout in DCPL */
-    if(H5Pset_layout(dcpl, H5D_VIRTUAL) < 0)
-        TEST_ERROR
+        /* Clear virtual layout in DCPL */
+        if(H5Pset_layout(dcpl, H5D_VIRTUAL) < 0)
+            TEST_ERROR
 
-    /* Create virtual dataspaces */
-    if((vspace[0] = H5Screate_simple(2, dims, mdims)) < 0)
-        TEST_ERROR
+        /* Create virtual dataspaces */
+        if((vspace[0] = H5Screate_simple(2, dims, mdims)) < 0)
+            TEST_ERROR
 
-    /* Create source dataspace */
-    dims[1] = 5;
-    if((srcspace = H5Screate_simple(2, dims, NULL)) < 0)
-        TEST_ERROR
+        /* Create source dataspace */
+        dims[1] = 5;
+        if((srcspace = H5Screate_simple(2, dims, NULL)) < 0)
+            TEST_ERROR
 
-    /* Select hyperslabs in virtual space */
-    stride[0] = 1;
-    stride[1] = 5;
-    count[0] = 1;
-    count[1] = H5S_UNLIMITED;
-    block[0] = 10;
-    block[1] = 5;
-    if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, stride, count, block) < 0)
-        TEST_ERROR
+        /* Select hyperslabs in virtual space */
+        stride[0] = 1;
+        stride[1] = 5;
+        count[0] = 1;
+        count[1] = H5S_UNLIMITED;
+        block[0] = 10;
+        block[1] = 5;
+        if(H5Sselect_hyperslab(vspace[0], H5S_SELECT_SET, start, stride, count, block) < 0)
+            TEST_ERROR
 
-    /* Add virtual layout mapping */
-    if(H5Pset_virtual(dcpl, vspace[0], printf_srcfilename, "%%src%%_dset%%%b", srcspace) < 0)
-        TEST_ERROR
+        /* Add virtual layout mapping */
+        if(H5Pset_virtual(dcpl, vspace[0], printf_srcfilename, "%%src%%_dset%%%b", srcspace) < 0)
+            TEST_ERROR
 
-    /* Create virtual file */
-    if((vfile = H5Fcreate(vfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
-        TEST_ERROR
+        /* Create virtual file */
+        if((vfile = H5Fcreate(vfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
 
-    /* Create virtual dataset */
-    if((vdset = H5Dcreate2(vfile, "v_dset", H5T_NATIVE_INT, vspace[0], H5P_DEFAULT, dcpl, dapl)) < 0)
-        TEST_ERROR
+        /* Create virtual dataset */
+        if((vdset = H5Dcreate2(vfile, "v_dset", H5T_NATIVE_INT, vspace[0], H5P_DEFAULT, dcpl, dapl)) < 0)
+            TEST_ERROR
 
-    /* Reopen virtual dataset and file if config option specified */
-    if(config & TEST_IO_REOPEN_VIRT) {
-        if(H5Dclose(vdset) < 0)
+        /* Reopen virtual dataset and file if config option specified */
+        if(config & TEST_IO_REOPEN_VIRT) {
+            if(H5Dclose(vdset) < 0)
+                TEST_ERROR
+            vdset = -1;
+            if(H5Fclose(vfile) < 0)
+                TEST_ERROR
+            vfile = -1;
+            if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+                TEST_ERROR
+            if((vdset = H5Dopen2(vfile, "v_dset", H5P_DEFAULT)) < 0)
+                TEST_ERROR
+        } /* end if */
+
+        /* Get VDS space */
+        if((filespace = H5Dget_space(vdset)) < 0)
             TEST_ERROR
-        vdset = -1;
-        if(H5Fclose(vfile) < 0)
+
+        /* Get VDS space dimensions */
+        if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
             TEST_ERROR
-        vfile = -1;
-        if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+        if(ndims != 2)
             TEST_ERROR
-        if((vdset = H5Dopen2(vfile, "v_dset", H5P_DEFAULT)) < 0)
+        if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
+            TEST_ERROR
+        if(dims[0] != 10)
+            TEST_ERROR
+        if(dims[1] != 0)
+            TEST_ERROR
+        if(mdims[0] != 10)
+            TEST_ERROR
+        if(mdims[1] != 20)
             TEST_ERROR
-    } /* end if */
 
-    /* Get VDS space */
-    if((filespace = H5Dget_space(vdset)) < 0)
-        TEST_ERROR
+        /* Close filespace */
+        if(H5Sclose(filespace) < 0)
+            TEST_ERROR
 
-    /* Get VDS space dimensions */
-    if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
-        TEST_ERROR
-    if(ndims != 2)
-        TEST_ERROR
-    if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
-        TEST_ERROR
-    if(dims[0] != 10)
-        TEST_ERROR
-    if(dims[1] != 0)
-        TEST_ERROR
-    if(mdims[0] != 10)
-        TEST_ERROR
-    if(mdims[1] != 20)
-        TEST_ERROR
+        /* Create 2 source files, one source dataset */
+        if((srcfile[0] = H5Fcreate(srcfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
+        if((srcdset[0] = H5Dcreate2(srcfile[0], "%src%_dset%0", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+            TEST_ERROR
+        if((srcfile[1] = H5Fcreate(srcfilename2, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
+            TEST_ERROR
 
-    /* Close filespace */
-    if(H5Sclose(filespace) < 0)
-        TEST_ERROR
+        /* Populate write buffer */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++)
+                buf[i][j] = (i * (int)mdims[1]) + j;
 
-    /* Create 2 source files, one source dataset */
-    if((srcfile[0] = H5Fcreate(srcfilename, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
-        TEST_ERROR
-    if((srcdset[0] = H5Dcreate2(srcfile[0], "%src%_dset%0", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
-        TEST_ERROR
-    if((srcfile[1] = H5Fcreate(srcfilename2, H5F_ACC_TRUNC, H5P_DEFAULT, fapl)) < 0)
-        TEST_ERROR
+        /* Initialize erbuf */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++)
+                erbuf[i][j] = fill;
 
-    /* Populate write buffer */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            buf[i][j] = (i * (int)mdims[1]) + j;
+        /* Write to srcdset[0] */
+        if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
+            TEST_ERROR
+        if(H5Dwrite(srcdset[0], H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
+            TEST_ERROR
 
-    /* Initialize erbuf */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            erbuf[i][j] = -1;
+        /* Update erbuf */
+        for(i = 0; i < 10; i++)
+            for(j = 0; j < 5; j++)
+                erbuf[i][j] = buf[i][j];
 
-    /* Write to srcdset[0] */
-    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
-        TEST_ERROR
-    if(H5Dwrite(srcdset[0], H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
-        TEST_ERROR
+        /* Close srcdset and srcfiles if config option specified */
+        if(config & TEST_IO_CLOSE_SRC) {
+            if(H5Dclose(srcdset[0]) < 0)
+                TEST_ERROR
+            srcdset[0] = -1;
+            if(H5Fclose(srcfile[0]) < 0)
+                TEST_ERROR
+            srcfile[0] = -1;
+            if(H5Fclose(srcfile[1]) < 0)
+                TEST_ERROR
+            srcfile[1] = -1;
+        } /* end if */
 
-    /* Update erbuf */
-    for(i = 0; i < 10; i++)
-        for(j = 0; j < 5; j++)
-            erbuf[i][j] = buf[i][j];
+        /* Reopen virtual dataset and file if config option specified */
+        if(config & TEST_IO_REOPEN_VIRT) {
+            if(H5Dclose(vdset) < 0)
+                TEST_ERROR
+            vdset = -1;
+            if(H5Fclose(vfile) < 0)
+                TEST_ERROR
+            vfile = -1;
+            if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+                TEST_ERROR
+            if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+                TEST_ERROR
+        } /* end if */
 
-    /* Close srcdset and srcfiles if config option specified */
-    if(config & TEST_IO_CLOSE_SRC) {
-        if(H5Dclose(srcdset[0]) < 0)
+        /* Get VDS space */
+        if((filespace = H5Dget_space(vdset)) < 0)
             TEST_ERROR
-        srcdset[0] = -1;
-        if(H5Fclose(srcfile[0]) < 0)
+
+        /* Get VDS space dimensions */
+        if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
             TEST_ERROR
-        srcfile[0] = -1;
-        if(H5Fclose(srcfile[1]) < 0)
+        if(ndims != 2)
             TEST_ERROR
-        srcfile[1] = -1;
-    } /* end if */
-
-    /* Reopen virtual dataset and file if config option specified */
-    if(config & TEST_IO_REOPEN_VIRT) {
-        if(H5Dclose(vdset) < 0)
+        if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
             TEST_ERROR
-        vdset = -1;
-        if(H5Fclose(vfile) < 0)
+        if(dims[0] != 10)
             TEST_ERROR
-        vfile = -1;
-        if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+        if(dims[1] != 5)
             TEST_ERROR
-        if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+        if(mdims[0] != 10)
+            TEST_ERROR
+        if(mdims[1] != 20)
             TEST_ERROR
-    } /* end if */
-
-    /* Get VDS space */
-    if((filespace = H5Dget_space(vdset)) < 0)
-        TEST_ERROR
 
-    /* Get VDS space dimensions */
-    if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
-        TEST_ERROR
-    if(ndims != 2)
-        TEST_ERROR
-    if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
-        TEST_ERROR
-    if(dims[0] != 10)
-        TEST_ERROR
-    if(dims[1] != 5)
-        TEST_ERROR
-    if(mdims[0] != 10)
-        TEST_ERROR
-    if(mdims[1] != 20)
-        TEST_ERROR
+        /* Close filespace */
+        if(H5Sclose(filespace) < 0)
+            TEST_ERROR
 
-    /* Close filespace */
-    if(H5Sclose(filespace) < 0)
-        TEST_ERROR
+        /* Read data through virtual dataset */
+        /* Reset rbuf */
+        HDmemset(rbuf[0], 0, sizeof(rbuf));
 
-    /* Read data through virtual dataset */
-    /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+        /* Select hyperslab in memory space */
+        if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
+            TEST_ERROR
 
-    /* Select hyperslab in memory space */
-    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
-        TEST_ERROR
+        /* Read data */
+        if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
+            TEST_ERROR
 
-    /* Read data */
-    if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
-        TEST_ERROR
+        /* Verify read data */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++) {
+                if(j >= (int)dims[1]) {
+                    if(rbuf[i][j] != 0)
+                        TEST_ERROR
+                } /* end if */
+                else
+                    if(rbuf[i][j] != erbuf[i][j])
+                        TEST_ERROR
+            } /* end for */
 
-    /* Verify read data */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
+        /* Reopen srcfile[1] if config option specified */
+        if(config & TEST_IO_CLOSE_SRC)
+            if((srcfile[1] = H5Fopen(srcfilename2, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
                 TEST_ERROR
 
-    /* Reopen srcfile[1] if config option specified */
-    if(config & TEST_IO_CLOSE_SRC)
-        if((srcfile[1] = H5Fopen(srcfilename2, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+        /* Create 2nd source dataset */
+        if((srcdset[1] = H5Dcreate2(srcfile[1], "%src%_dset%1", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR
 
-    /* Create 2nd source dataset */
-    if((srcdset[1] = H5Dcreate2(srcfile[1], "%src%_dset%1", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
-        TEST_ERROR
+        /* Adjust write buffer */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++)
+                buf[i][j] += (int)mdims[0] * (int)mdims[1];
 
-    /* Adjust write buffer */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            buf[i][j] += (int)mdims[0] * (int)mdims[1];
+        /* Write to srcdset[1] */
+        if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
+            TEST_ERROR
+        if(H5Dwrite(srcdset[1], H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
+            TEST_ERROR
 
-    /* Write to srcdset[1] */
-    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, block, NULL) < 0)
-        TEST_ERROR
-    if(H5Dwrite(srcdset[1], H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, buf[0]) < 0)
-        TEST_ERROR
+        /* Update erbuf */
+        for(i = 0; i < 10; i++)
+            for(j = 0; j < 5; j++)
+                erbuf[i][j + 5] = buf[i][j];
 
-    /* Update erbuf */
-    for(i = 0; i < 10; i++)
-        for(j = 0; j < 5; j++)
-            erbuf[i][j + 5] = buf[i][j];
+        /* Close srcdset[1] and srcfile[1] if config option specified */
+        if(config & TEST_IO_CLOSE_SRC) {
+            if(H5Dclose(srcdset[1]) < 0)
+                TEST_ERROR
+            srcdset[1] = -1;
+            if(H5Fclose(srcfile[1]) < 0)
+                TEST_ERROR
+            srcfile[1] = -1;
+        } /* end if */
 
-    /* Close srcdset[1] and srcfile[1] if config option specified */
-    if(config & TEST_IO_CLOSE_SRC) {
-        if(H5Dclose(srcdset[1]) < 0)
-            TEST_ERROR
-        srcdset[1] = -1;
-        if(H5Fclose(srcfile[1]) < 0)
+        /* Reopen virtual dataset and file if config option specified */
+        if(config & TEST_IO_REOPEN_VIRT) {
+            if(H5Dclose(vdset) < 0)
+                TEST_ERROR
+            vdset = -1;
+            if(H5Fclose(vfile) < 0)
+                TEST_ERROR
+            vfile = -1;
+            if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+                TEST_ERROR
+            if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+                TEST_ERROR
+        } /* end if */
+
+        /* Get VDS space */
+        if((filespace = H5Dget_space(vdset)) < 0)
             TEST_ERROR
-        srcfile[1] = -1;
-    } /* end if */
 
-    /* Reopen virtual dataset and file if config option specified */
-    if(config & TEST_IO_REOPEN_VIRT) {
-        if(H5Dclose(vdset) < 0)
+        /* Get VDS space dimensions */
+        if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
             TEST_ERROR
-        vdset = -1;
-        if(H5Fclose(vfile) < 0)
+        if(ndims != 2)
             TEST_ERROR
-        vfile = -1;
-        if((vfile = H5Fopen(vfilename, H5F_ACC_RDWR, H5P_DEFAULT)) < 0)
+        if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
             TEST_ERROR
-        if((vdset = H5Dopen2(vfile, "v_dset", dapl)) < 0)
+        if(dims[0] != 10)
+            TEST_ERROR
+        if(dims[1] != 10)
+            TEST_ERROR
+        if(mdims[0] != 10)
+            TEST_ERROR
+        if(mdims[1] != 20)
             TEST_ERROR
-    } /* end if */
-
-    /* Get VDS space */
-    if((filespace = H5Dget_space(vdset)) < 0)
-        TEST_ERROR
 
-    /* Get VDS space dimensions */
-    if((ndims = H5Sget_simple_extent_ndims(filespace)) < 0)
-        TEST_ERROR
-    if(ndims != 2)
-        TEST_ERROR
-    if(H5Sget_simple_extent_dims(filespace, dims, mdims) < 0)
-        TEST_ERROR
-    if(dims[0] != 10)
-        TEST_ERROR
-    if(dims[1] != 10)
-        TEST_ERROR
-    if(mdims[0] != 10)
-        TEST_ERROR
-    if(mdims[1] != 20)
-        TEST_ERROR
+        /* Close filespace */
+        if(H5Sclose(filespace) < 0)
+            TEST_ERROR
 
-    /* Close filespace */
-    if(H5Sclose(filespace) < 0)
-        TEST_ERROR
+        /* Read data through virtual dataset */
+        /* Reset rbuf */
+        HDmemset(rbuf[0], 0, sizeof(rbuf));
 
-    /* Read data through virtual dataset */
-    /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+        /* Select hyperslab in memory space */
+        if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
+            TEST_ERROR
 
-    /* Select hyperslab in memory space */
-    if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
-        TEST_ERROR
+        /* Read data */
+        if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
+            TEST_ERROR
 
-    /* Read data */
-    if(H5Dread(vdset, H5T_NATIVE_INT, memspace, H5S_ALL, H5P_DEFAULT, rbuf[0]) < 0)
-        TEST_ERROR
+        /* Verify read data */
+        for(i = 0; i < (int)mdims[0]; i++)
+            for(j = 0; j < (int)mdims[1]; j++) {
+                if(j >= (int)dims[1]) {
+                    if(rbuf[i][j] != 0)
+                        TEST_ERROR
+                } /* end if */
+                else
+                    if(rbuf[i][j] != erbuf[i][j])
+                        TEST_ERROR
+            } /* end for */
 
-    /* Verify read data */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
+        /* Close */
+        if(!(config & TEST_IO_CLOSE_SRC)) {
+            if(H5Dclose(srcdset[0]) < 0)
                 TEST_ERROR
-
-    /* Close */
-    if(!(config & TEST_IO_CLOSE_SRC)) {
-        if(H5Dclose(srcdset[0]) < 0)
+            srcdset[0] = -1;
+            if(H5Dclose(srcdset[1]) < 0)
+                TEST_ERROR
+            srcdset[1] = -1;
+            if(H5Fclose(srcfile[0]) < 0)
+                TEST_ERROR
+            srcfile[0] = -1;
+            if(H5Fclose(srcfile[1]) < 0)
+                TEST_ERROR
+            srcfile[1] = -1;
+        } /* end if */
+        if(H5Dclose(vdset) < 0)
             TEST_ERROR
-        srcdset[0] = -1;
-        if(H5Dclose(srcdset[1]) < 0)
+        vdset = -1;
+        if(H5Fclose(vfile) < 0)
             TEST_ERROR
-        srcdset[1] = -1;
-        if(H5Fclose(srcfile[0]) < 0)
+        vfile = -1;
+        if(H5Sclose(srcspace) < 0)
             TEST_ERROR
-        srcfile[0] = -1;
-        if(H5Fclose(srcfile[1]) < 0)
+        srcspace = -1;
+        if(H5Sclose(vspace[0]) < 0)
             TEST_ERROR
-        srcfile[1] = -1;
+        vspace[0] = -1;
     } /* end if */
-    if(H5Dclose(vdset) < 0)
-        TEST_ERROR
-    vdset = -1;
-    if(H5Fclose(vfile) < 0)
-        TEST_ERROR
-    vfile = -1;
-    if(H5Sclose(srcspace) < 0)
-        TEST_ERROR
-    srcspace = -1;
-    if(H5Sclose(vspace[0]) < 0)
-        TEST_ERROR
-    vspace[0] = -1;
 
 
     /*
@@ -6751,7 +6877,7 @@ test_printf(unsigned config, hid_t fapl)
     start[1] = 0;
 
     /* Add virtual layout mappings */
-    if(H5Pset_virtual(dcpl, vspace[0], config & TEST_IO_DIFFERENT_FILE ? srcfilename : ".", "src_dset_a%b%%", srcspace) < 0)
+    if(H5Pset_virtual(dcpl, vspace[0], config & TEST_IO_DIFFERENT_FILE ? srcfilename : ".", "%bsrc_dset_a%b%%", srcspace) < 0)
         TEST_ERROR
     if(H5Pset_virtual(dcpl, vspace[1], config & TEST_IO_DIFFERENT_FILE ? srcfilename : ".", "src_dset_b%b%%%%", srcspace) < 0)
         TEST_ERROR
@@ -6828,7 +6954,7 @@ test_printf(unsigned config, hid_t fapl)
                 TEST_ERROR
 
     /* Create 2 source datasets */
-    if((srcdset[0] = H5Dcreate2(srcfile[0], "src_dset_a0%", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+    if((srcdset[0] = H5Dcreate2(srcfile[0], "0src_dset_a0%", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         TEST_ERROR
     if((srcdset[1] = H5Dcreate2(srcfile[0], "src_dset_b0%%", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         TEST_ERROR
@@ -6841,7 +6967,7 @@ test_printf(unsigned config, hid_t fapl)
     /* Initialize erbuf */
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++)
-            erbuf[i][j] = -1;
+            erbuf[i][j] = fill;
 
     /* Write to srcdset[0] */
     block[0] = 10;
@@ -6924,12 +7050,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -6941,9 +7062,15 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Reopen srcfile if config option specified */
     if((config & TEST_IO_CLOSE_SRC) && (config & TEST_IO_DIFFERENT_FILE))
@@ -7022,12 +7149,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -7039,9 +7161,15 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Verify read data */
     for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            if(rbuf[i][j] != erbuf[i][j])
-                TEST_ERROR
+        for(j = 0; j < (int)mdims[1]; j++) {
+            if(j >= (int)dims[1]) {
+                if(rbuf[i][j] != 0)
+                    TEST_ERROR
+            } /* end if */
+            else
+                if(rbuf[i][j] != erbuf[i][j])
+                    TEST_ERROR
+        } /* end for */
 
     /* Close VDS and reopen with view set to H5D_VDS_FIRST_MISSING, reopen file
      * as well if config option specified */
@@ -7086,12 +7214,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -7105,7 +7228,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -7119,7 +7242,7 @@ test_printf(unsigned config, hid_t fapl)
             TEST_ERROR
 
     /* Create 4th source dataset */
-    if((srcdset[3] = H5Dcreate2(srcfile[0], "src_dset_a2%", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
+    if((srcdset[3] = H5Dcreate2(srcfile[0], "2src_dset_a2%", H5T_NATIVE_INT, srcspace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         TEST_ERROR
 
     /* Adjust write buffer */
@@ -7190,12 +7313,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -7209,7 +7327,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -7260,12 +7378,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -7279,7 +7392,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else
@@ -7330,12 +7443,7 @@ test_printf(unsigned config, hid_t fapl)
 
     /* Read data through virtual dataset */
     /* Reset rbuf */
-    //HDmemset(rbuf[0], 0, sizeof(rbuf)); VDSINC
-    /* Initialize erbuf - used now instead of setting fill value because fill
-     * values do not work VDSINC */
-    for(i = 0; i < (int)mdims[0]; i++)
-        for(j = 0; j < (int)mdims[1]; j++)
-            rbuf[i][j] = -1;
+    HDmemset(rbuf[0], 0, sizeof(rbuf));
 
     /* Select hyperslab in memory space */
     if(H5Sselect_hyperslab(memspace, H5S_SELECT_SET, start, NULL, dims, NULL) < 0)
@@ -7349,7 +7457,7 @@ test_printf(unsigned config, hid_t fapl)
     for(i = 0; i < (int)mdims[0]; i++)
         for(j = 0; j < (int)mdims[1]; j++) {
             if(j >= (int)dims[1]) {
-                if(rbuf[i][j] != -1)
+                if(rbuf[i][j] != 0)
                     TEST_ERROR
             } /* end if */
             else