Let users specify an initial size for the core VFD backing buffer.

c++/src/H5FaccProp.cpp

@@ -197,6 +197,8 @@ FileAccPropList::getFamilyOffset() const
 // Function:    FileAccPropList::setCore
 ///\brief       Modifies this file access property list to use the \c H5FD_CORE
 ///             driver.
+///\param       initial_size - IN: Specifies the initial size of the backing
+///                                  memory buffer, in bytes
 ///\param       increment - IN: Specifies how much memory to increase each
 ///                             time more memory is needed, in bytes
 ///\param       backing_store - IN: Indicating whether to write the file
@@ -207,9 +209,9 @@ FileAccPropList::getFamilyOffset() const
 ///             refer to the H5Pset_fapl_core API in the HDF5 C Reference Manual.
 //--------------------------------------------------------------------------
 void
-FileAccPropList::setCore(size_t increment, bool backing_store) const
+FileAccPropList::setCore(size_t initial_size, size_t increment, bool backing_store) const
 {
-    herr_t ret_value = H5Pset_fapl_core(id, increment, backing_store);
+    herr_t ret_value = H5Pset_fapl_core(id, initial_size, increment, backing_store);
     if (ret_value < 0) {
         throw PropListIException("FileAccPropList::setCore", "H5Pset_fapl_core failed");
     }
@@ -218,15 +220,16 @@ FileAccPropList::setCore(size_t increment, bool backing_store) const
 //--------------------------------------------------------------------------
 // Function:    FileAccPropList::getCore
 ///\brief       Queries core file driver properties.
+///\param       initial_size - OUT: Initial size of the backing memory buffer, in bytes
 ///\param       increment - OUT: Size of memory increment, in bytes
 ///\param       backing_store - OUT: Indicating whether to write the file
 ///                                  contents to disk when the file is closed
 ///\exception   H5::PropListIException
 //--------------------------------------------------------------------------
 void
-FileAccPropList::getCore(size_t &increment, bool &backing_store) const
+FileAccPropList::getCore(size_t &initial_size, size_t &increment, bool &backing_store) const
 {
-    herr_t ret_value = H5Pget_fapl_core(id, &increment, &backing_store);
+    herr_t ret_value = H5Pget_fapl_core(id, &initial_size, &increment, &backing_store);
     if (ret_value < 0) {
         throw PropListIException("FileAccPropList::getCore", "H5Pget_fapl_core failed");
     }

c++/src/H5FaccProp.h

@@ -49,10 +49,10 @@ class H5CPP_DLL FileAccPropList : public PropList {
 
     // Modifies this file access property list to use the H5FD_CORE
     // driver.
-    void setCore(size_t increment, bool backing_store) const;
+    void setCore(size_t initial_size, size_t increment, bool backing_store) const;
 
     // Queries H5FD_CORE driver properties.
-    void getCore(size_t &increment, bool &backing_store) const;
+    void getCore(size_t &initial_size, size_t &increment, bool &backing_store) const;
 
     // Sets this file access properties list to the family driver.
     void setFamily(hsize_t memb_size, const FileAccPropList &memb_plist) const;

docs/doxygen/H5version_doxygen.cmake

@@ -33,10 +33,12 @@ list (APPEND _doxygen_predefined_entries
   "H5Ovisit=H5Ovisit3"
   "H5Ovisit_by_name=H5Ovisit_by_name3"
   "H5Pencode=H5Pencode2"
+  "H5Pget_fapl_core=H5Pget_fapl_core2"
   "H5Pget_filter=H5Pget_filter2"
   "H5Pget_filter_by_id=H5Pget_filter_by_id2"
   "H5Pinsert=H5Pinsert2"
   "H5Pregister=H5Pregister2"
+  "H5Pset_fapl_core=H5Pset_fapl_core2"
   "H5Rdereference=H5Rdereference2"
   "H5Rget_obj_type=H5Rget_obj_type2"
   "H5Sencode=H5Sencode2"

docs/doxygen/dox/ModifiedRegionWrites.dox

@@ -27,7 +27,7 @@
 
  * The Core VFD is configured via the following API call:
  * \code
- *    herr_t H5Pset_fapl_core(hid_t fapl_id, size_t increment, bool backing_store)
+ *    herr_t H5Pset_fapl_core(hid_t fapl_id, size_t initial_size, size_t increment, bool backing_store)
  * \endcode
  *
  * The backing_store parameter sets whether or not changes are propagated to physical storage on

fortran/src/H5Pf.c

@@ -859,6 +859,7 @@ h5pget_alignment_c(hid_t_f *prp_id, hsize_t_f *threshold, hsize_t_f *alignment)
  *  to use malloc() and free()
  * INPUTS
  *  prp_id - property list identifier
+ *  initial_size - Initial size of the backing memory buffer in bytes
  *  increment - File block size in bytes
  *  flag - Boolean flag indicating whether to write the
  *  file contents to disk when the file is closed.
@@ -867,22 +868,24 @@ h5pget_alignment_c(hid_t_f *prp_id, hsize_t_f *threshold, hsize_t_f *alignment)
  * SOURCE
  */
 int_f
-h5pset_fapl_core_c(hid_t_f *prp_id, size_t_f *increment, int_f *flag)
+h5pset_fapl_core_c(hid_t_f *prp_id, size_t_f *initial_size, size_t_f *increment, int_f *flag)
 /******/
 {
     int    ret_value = -1;
     hid_t  c_prp_id;
     herr_t ret = -1;
+    size_t c_initial_size;
     size_t c_increment;
     bool   c_backing_store;
+    c_initial_size  = (size_t)*initial_size;
     c_increment     = (size_t)*increment;
     c_backing_store = (bool)*flag;
 
     /*
      * Call H5Pset_fapl_core function.
      */
     c_prp_id = (hid_t)*prp_id;
-    ret      = H5Pset_fapl_core(c_prp_id, c_increment, c_backing_store);
+    ret      = H5Pset_fapl_core(c_prp_id, c_initial_size, c_increment, c_backing_store);
     if (ret < 0)
         return ret_value;
     ret_value = 0;
@@ -897,29 +900,32 @@ h5pset_fapl_core_c(hid_t_f *prp_id, size_t_f *increment, int_f *flag)
  *  property list is set to the core drive
  * INPUTS
  *  prp_id - property list identifier
+ *  Outputs      initial_size - Initial size of the backing memory buffer in bytes
  *  Outputs      increment - File block size in bytes
  * RETURNS
  *  0 on success, -1 on failure
  * SOURCE
  */
 int_f
-h5pget_fapl_core_c(hid_t_f *prp_id, size_t_f *increment, int_f *flag)
+h5pget_fapl_core_c(hid_t_f *prp_id, size_t_f *initial_size, size_t_f *increment, int_f *flag)
 /******/
 {
     int    ret_value = -1;
     hid_t  c_prp_id;
-    herr_t ret         = -1;
-    size_t c_increment = 0;
+    herr_t ret            = -1;
+    size_t c_initial_size = 0;
+    size_t c_increment    = 0;
     bool   c_backing_store;
     *flag = 0;
     /*
      * Call H5Pset_fapl_core function.
      */
     c_prp_id = (hid_t)*prp_id;
-    ret      = H5Pget_fapl_core(c_prp_id, &c_increment, &c_backing_store);
+    ret      = H5Pget_fapl_core(c_prp_id, &c_initial_size, &c_increment, &c_backing_store);
     if (ret < 0)
         return ret_value;
-    *increment = (size_t_f)c_increment;
+    *initial_size = (size_t_f)c_initial_size;
+    *increment    = (size_t_f)c_increment;
     if (c_backing_store > 0)
         *flag = 1;
     ret_value = 0;

fortran/src/H5Pff.F90

@@ -1121,32 +1121,35 @@ END SUBROUTINE h5pget_alignment_f
 !! \brief Modifies the file access property list to use the H5FD_CORE driver.
 !!
 !! \param prp_id        File access property list identifier.
+!! \param initial_size  Initial size, in bytes, of the backing memory buffer.
 !! \param increment     Size, in bytes, of memory increments.
 !! \param backing_store Boolean flag indicating whether to write the file contents to disk when the file is closed.
 !! \param hdferr        \fortran_error
 !!
 !! See C API: @ref H5Pset_fapl_core()
 !!
-  SUBROUTINE h5pset_fapl_core_f(prp_id, increment, backing_store, hdferr)
+  SUBROUTINE h5pset_fapl_core_f(prp_id, initial_size, increment, backing_store, hdferr)
     IMPLICIT NONE
     INTEGER(HID_T), INTENT(IN) :: prp_id
+    INTEGER(SIZE_T), INTENT(IN) :: initial_size
     INTEGER(SIZE_T), INTENT(IN) :: increment
     LOGICAL, INTENT(IN) :: backing_store
     INTEGER, INTENT(OUT) :: hdferr
     INTEGER :: backing_store_flag
     INTERFACE
-       INTEGER FUNCTION h5pset_fapl_core_c(prp_id, increment, backing_store_flag) &
+       INTEGER FUNCTION h5pset_fapl_core_c(prp_id, initial_size, increment, backing_store_flag) &
             BIND(C,NAME='h5pset_fapl_core_c')
          IMPORT :: HID_T, SIZE_T
          IMPLICIT NONE
          INTEGER(HID_T), INTENT(IN) :: prp_id
+         INTEGER(SIZE_T), INTENT(IN) :: initial_size
          INTEGER(SIZE_T), INTENT(IN) :: increment
          INTEGER :: backing_store_flag
        END FUNCTION h5pset_fapl_core_c
     END INTERFACE
     backing_store_flag = 0
     IF(backing_store) backing_store_flag = 1
-    hdferr = h5pset_fapl_core_c(prp_id, increment, backing_store_flag)
+    hdferr = h5pset_fapl_core_c(prp_id, initial_size, increment, backing_store_flag)
   END SUBROUTINE h5pset_fapl_core_f
 
 !>
@@ -1155,32 +1158,35 @@ END SUBROUTINE h5pset_fapl_core_f
 !! \brief Queries core file driver properties.
 !!
 !! \param prp_id        File access property list identifier.
+!! \param initial_size  Initial size, in bytes, of the backing memory buffer.
 !! \param increment     Size, in bytes, of memory increments.
 !! \param backing_store Boolean flag indicating whether to write the file contents to disk when the file is closed.
 !! \param hdferr        \fortran_error
 !!
 !! See C API: @ref H5Pget_fapl_core()
 !!
-  SUBROUTINE h5pget_fapl_core_f(prp_id, increment, backing_store, hdferr)
+  SUBROUTINE h5pget_fapl_core_f(prp_id, initial_size, increment, backing_store, hdferr)
     IMPLICIT NONE
     INTEGER(HID_T), INTENT(IN) :: prp_id
+    INTEGER(SIZE_T), INTENT(OUT) :: initial_size
     INTEGER(SIZE_T), INTENT(OUT) :: increment
     LOGICAL, INTENT(OUT) :: backing_store
     INTEGER, INTENT(OUT) :: hdferr
     INTEGER :: backing_store_flag
 
     INTERFACE
-       INTEGER FUNCTION h5pget_fapl_core_c(prp_id, increment, backing_store_flag) &
+       INTEGER FUNCTION h5pget_fapl_core_c(prp_id, initial_size, increment, backing_store_flag) &
             BIND(C,NAME='h5pget_fapl_core_c')
          IMPORT :: HID_T,SIZE_T
          IMPLICIT NONE
          INTEGER(HID_T), INTENT(IN) :: prp_id
+         INTEGER(SIZE_T), INTENT(OUT) :: initial_size
          INTEGER(SIZE_T), INTENT(OUT) :: increment
          INTEGER :: backing_store_flag
        END FUNCTION h5pget_fapl_core_c
     END INTERFACE
 
-    hdferr = h5pget_fapl_core_c(prp_id, increment, backing_store_flag)
+    hdferr = h5pget_fapl_core_c(prp_id, initial_size, increment, backing_store_flag)
     backing_store =.FALSE.
     IF (backing_store_flag .EQ. 1) backing_store =.TRUE.
   END SUBROUTINE h5pget_fapl_core_f
@@ -7012,4 +7018,3 @@ END FUNCTION H5Pget_actual_selection_io_mode
    END SUBROUTINE h5pget_actual_selection_io_mode_f
 
 END MODULE H5P
-

fortran/src/H5f90proto.h

@@ -397,8 +397,8 @@ H5FC_DLL int_f h5pget_fapl_sec2_c(hid_t_f *prp_id, int_f *sec2);
 #endif
 H5FC_DLL int_f h5pset_alignment_c(hid_t_f *prp_id, hsize_t_f *threshold, hsize_t_f *alignment);
 H5FC_DLL int_f h5pget_alignment_c(hid_t_f *prp_id, hsize_t_f *threshold, hsize_t_f *alignment);
-H5FC_DLL int_f h5pget_fapl_core_c(hid_t_f *prp_id, size_t_f *increment, int_f *flag);
-H5FC_DLL int_f h5pset_fapl_core_c(hid_t_f *prp_id, size_t_f *increment, int_f *flag);
+H5FC_DLL int_f h5pget_fapl_core_c(hid_t_f *prp_id, size_t_f *initial_size, size_t_f *increment, int_f *flag);
+H5FC_DLL int_f h5pset_fapl_core_c(hid_t_f *prp_id, size_t_f *initial_size, size_t_f *increment, int_f *flag);
 H5FC_DLL int_f h5pset_fapl_family_c(hid_t_f *prp_id, hsize_t_f *memb_size, hid_t_f *memb_plist);
 H5FC_DLL int_f h5pget_fapl_family_c(hid_t_f *prp_id, hsize_t_f *memb_size, hid_t_f *memb_plist);
 H5FC_DLL int_f h5pset_cache_c(hid_t_f *prp_id, int_f *mdc_nelmts, size_t_f *rdcc_nelmts,

hl/src/H5LT.c

@@ -794,7 +794,7 @@ H5LTopen_file_image(void *buf_ptr, size_t buf_size, unsigned flags)
         alloc_incr = min_incr;
 
     /* Configure FAPL to use the core file driver */
-    if (H5Pset_fapl_core(fapl, alloc_incr, false) < 0)
+    if (H5Pset_fapl_core(fapl, 0, alloc_incr, false) < 0)
         goto out;
 
     /* Set callbacks for file image ops ONLY if the file image is NOT copied */

java/hdf/hdf5lib/H5.java

@@ -17230,6 +17230,8 @@ public static void H5Pset_copy_object(long ocp_plist_id, int copy_options) throw
      *
      * @param fapl_id
      *            IN: File access property list identifier
+     * @param initial_size
+     *            OUT: initial size of the backing memory buffer
      * @param increment
      *            OUT: how much to grow the memory each time
      * @param backing_store
@@ -17238,23 +17240,28 @@ public static void H5Pset_copy_object(long ocp_plist_id, int copy_options) throw
      * @exception HDF5LibraryException
      *            Error from the HDF5 Library.
      * @exception NullPointerException
-     *            increment or backing_store is null.
+     *            initial_size, increment, or backing_store is null.
      *
      **/
-    public static void H5Pget_fapl_core(long fapl_id, long[] increment, boolean[] backing_store)
+    public static void H5Pget_fapl_core(long fapl_id, long[] initial_size, long[] increment,
+                                        boolean[] backing_store)
         throws HDF5LibraryException, NullPointerException
     {
-        if (increment == null || increment.length < 1 || backing_store == null || backing_store.length < 1) {
-            throw new NullPointerException("increment or backing_store is null or has insufficient length");
+        if (initial_size == null || initial_size.length < 1 || increment == null || increment.length < 1 ||
+            backing_store == null || backing_store.length < 1) {
+            throw new NullPointerException(
+                "initial_size, increment, or backing_store is null or has insufficient length");
         }
 
         try (Arena arena = Arena.ofConfined()) {
+            MemorySegment initial_size_segment  = arena.allocate(ValueLayout.JAVA_LONG, 1);
             MemorySegment increment_segment     = arena.allocate(ValueLayout.JAVA_LONG, 1);
             MemorySegment backing_store_segment = arena.allocate(ValueLayout.JAVA_BOOLEAN, 1);
-            int retVal = org.hdfgroup.javahdf5.hdf5_h.H5Pget_fapl_core(fapl_id, increment_segment,
-                                                                       backing_store_segment);
+            int retVal                          = org.hdfgroup.javahdf5.hdf5_h.H5Pget_fapl_core(
+                fapl_id, initial_size_segment, increment_segment, backing_store_segment);
             if (retVal < 0)
                 h5libraryError();
+            initial_size[0]  = initial_size_segment.get(ValueLayout.JAVA_LONG, 0);
             increment[0]     = increment_segment.get(ValueLayout.JAVA_LONG, 0);
             backing_store[0] = backing_store_segment.get(ValueLayout.JAVA_BOOLEAN, 0);
         }
@@ -17267,6 +17274,8 @@ public static void H5Pget_fapl_core(long fapl_id, long[] increment, boolean[] ba
      *
      * @param fapl_id
      *            IN: File access property list identifier
+     * @param initial_size
+     *            IN: initial size of the backing memory buffer
      * @param increment
      *            IN: how much to grow the memory each time
      * @param backing_store
@@ -17278,10 +17287,11 @@ public static void H5Pget_fapl_core(long fapl_id, long[] increment, boolean[] ba
      *            Error from the HDF5 Library.
      *
      **/
-    public static int H5Pset_fapl_core(long fapl_id, long increment, boolean backing_store)
+    public static int H5Pset_fapl_core(long fapl_id, long initial_size, long increment, boolean backing_store)
         throws HDF5LibraryException
     {
-        int retVal = org.hdfgroup.javahdf5.hdf5_h.H5Pset_fapl_core(fapl_id, increment, backing_store);
+        int retVal =
+            org.hdfgroup.javahdf5.hdf5_h.H5Pset_fapl_core(fapl_id, initial_size, increment, backing_store);
         if (retVal < 0) {
             h5libraryError();
         }

java/jtest/TestH5Pffm.java

@@ -1588,17 +1588,21 @@ public void testH5Pset_fapl_core()
             assertTrue("H5Pcreate fapl failed", isValidId(fapl));
 
             // Set core (memory) VFD with 1MB increment and backing store enabled
+            long initialSize     = 0;
             long increment       = 1024 * 1024; // 1MB increments
             boolean backingStore = true;        // Enable backing store
-            int result           = hdf5_h.H5Pset_fapl_core(fapl, increment, backingStore);
+            int result           = hdf5_h.H5Pset_fapl_core(fapl, initialSize, increment, backingStore);
             assertTrue("H5Pset_fapl_core failed", isSuccess(result));
 
             // Get core VFD settings
+            MemorySegment initialSizeSeg  = arena.allocate(ValueLayout.JAVA_LONG);
             MemorySegment incrementSeg    = arena.allocate(ValueLayout.JAVA_LONG);
             MemorySegment backingStoreSeg = arena.allocate(ValueLayout.JAVA_BOOLEAN);
-            result                        = hdf5_h.H5Pget_fapl_core(fapl, incrementSeg, backingStoreSeg);
+            result = hdf5_h.H5Pget_fapl_core(fapl, initialSizeSeg, incrementSeg, backingStoreSeg);
             assertTrue("H5Pget_fapl_core failed", isSuccess(result));
 
+            long retInitialSize = initialSizeSeg.get(ValueLayout.JAVA_LONG, 0);
+            assertEquals("Initial size should match", initialSize, retInitialSize);
             long retIncrement = incrementSeg.get(ValueLayout.JAVA_LONG, 0);
             assertEquals("Increment should match", increment, retIncrement);
 
@@ -1702,7 +1706,7 @@ public void testH5Pget_driver()
             assertTrue("Default driver ID should be valid", isValidId(driverId));
 
             // Set core VFD
-            int result = hdf5_h.H5Pset_fapl_core(fapl, 1024, false);
+            int result = hdf5_h.H5Pset_fapl_core(fapl, 0, 1024, false);
             assertTrue("H5Pset_fapl_core failed", isSuccess(result));
 
             // Get driver again (should be core)

java/src-jni/hdf/hdf5lib/H5.java

@@ -11457,6 +11457,8 @@ public synchronized static native void H5Pset_copy_object(long ocp_plist_id, int
      *
      * @param fapl_id
      *            IN: File access property list identifier
+     * @param initial_size
+     *            OUT: initial size of the backing memory buffer
      * @param increment
      *            OUT: how much to grow the memory each time
      * @param backing_store
@@ -11466,8 +11468,8 @@ public synchronized static native void H5Pset_copy_object(long ocp_plist_id, int
      *            Error from the HDF5 Library.
      *
      **/
-    public synchronized static native void H5Pget_fapl_core(long fapl_id, long[] increment,
-                                                            boolean[] backing_store)
+    public synchronized static native void H5Pget_fapl_core(long fapl_id, long[] initial_size,
+                                                            long[] increment, boolean[] backing_store)
         throws HDF5LibraryException, NullPointerException;
 
     /**
@@ -11477,6 +11479,8 @@ public synchronized static native void H5Pget_fapl_core(long fapl_id, long[] inc
      *
      * @param fapl_id
      *            IN: File access property list identifier
+     * @param initial_size
+     *            IN: initial size of the backing memory buffer
      * @param increment
      *            IN: how much to grow the memory each time
      * @param backing_store
@@ -11488,7 +11492,7 @@ public synchronized static native void H5Pget_fapl_core(long fapl_id, long[] inc
      *            Error from the HDF5 Library.
      *
      **/
-    public synchronized static native int H5Pset_fapl_core(long fapl_id, long increment,
+    public synchronized static native int H5Pset_fapl_core(long fapl_id, long initial_size, long increment,
                                                            boolean backing_store)
         throws HDF5LibraryException, NullPointerException;