Brings many parallel changes from develop

11 files changed, 413 insertions, 565 deletions

diff --git a/src/H5Clog_json.c b/src/H5Clog_json.c
index 6d048f1..731d741 100644
--- a/src/H5Clog_json.c
+++ b/src/H5Clog_json.c
@@ -173,7 +173,7 @@ H5C__json_write_log_message(H5C_log_json_udata_t *json_udata)
 
     /* Write the log message and flush */
     n_chars = HDstrlen(json_udata->message);
-    if ((int)n_chars != HDfprintf(json_udata->outfile, json_udata->message))
+    if ((int)n_chars != HDfprintf(json_udata->outfile, "%s", json_udata->message))
         HGOTO_ERROR(H5E_CACHE, H5E_LOGGING, FAIL, "error writing log message")
     HDmemset((void *)(json_udata->message), 0, (size_t)(n_chars * sizeof(char)));
 
diff --git a/src/H5Clog_trace.c b/src/H5Clog_trace.c
index 8c79d7b..c30f79e 100644
--- a/src/H5Clog_trace.c
+++ b/src/H5Clog_trace.c
@@ -168,7 +168,7 @@ H5C__trace_write_log_message(H5C_log_trace_udata_t *trace_udata)
 
     /* Write the log message and flush */
     n_chars = HDstrlen(trace_udata->message);
-    if ((int)n_chars != HDfprintf(trace_udata->outfile, trace_udata->message))
+    if ((int)n_chars != HDfprintf(trace_udata->outfile, "%s", trace_udata->message))
         HGOTO_ERROR(H5E_CACHE, H5E_LOGGING, FAIL, "error writing log message")
     HDmemset((void *)(trace_udata->message), 0, (size_t)(n_chars * sizeof(char)));
 
diff --git a/src/H5Cmpio.c b/src/H5Cmpio.c
index d26c508..12dde12 100644
--- a/src/H5Cmpio.c
+++ b/src/H5Cmpio.c
@@ -105,9 +105,9 @@ static herr_t H5C__flush_candidates_in_ring(H5F_t *f, H5C_ring_t ring, unsigned
  *
  *              We construct the table as follows.  Let:
  *
- *                  n = num_candidates / mpi_size;
+ *                      n = num_candidates / mpi_size;
  *
- *                  m = num_candidates % mpi_size;
+ *                      m = num_candidates % mpi_size;
  *
  *              Now allocate an array of integers of length mpi_size + 1,
  *              and call this array candidate_assignment_table.
@@ -127,10 +127,10 @@ static herr_t H5C__flush_candidates_in_ring(H5F_t *f, H5C_ring_t ring, unsigned
  *              Once the table is constructed, we determine the first and
  *              last entry this process is to flush as follows:
  *
- *                  first_entry_to_flush = candidate_assignment_table[mpi_rank]
+ *              first_entry_to_flush = candidate_assignment_table[mpi_rank]
  *
  *              last_entry_to_flush =
- *                  candidate_assignment_table[mpi_rank + 1] - 1;
+ *                      candidate_assignment_table[mpi_rank + 1] - 1;
  *
  *              With these values determined, we simply scan through the
  *              candidate list, marking all entries in the range
@@ -737,7 +737,7 @@ H5C_mark_entries_as_clean(H5F_t *f, unsigned ce_array_len, haddr_t *ce_array_ptr
      * of the pre_serialize / serialize routines, this may
      * cease to be the case -- requiring a review of this
      * point.
-     *                    JRM -- 4/7/15
+     *                                  JRM -- 4/7/15
      */
     entries_cleared  = 0;
     entries_examined = 0;
@@ -885,15 +885,16 @@ H5C__collective_write(H5F_t *f)
 {
     H5AC_t *         cache_ptr;
     H5FD_mpio_xfer_t orig_xfer_mode = H5FD_MPIO_COLLECTIVE;
+    void *           base_buf;
     int              count;
     int *            length_array = NULL;
     MPI_Aint *       buf_array    = NULL;
     MPI_Aint *       offset_array = NULL;
-    MPI_Datatype     btype;
-    hbool_t          btype_created = FALSE;
-    MPI_Datatype     ftype;
-    hbool_t          ftype_created = FALSE;
+    MPI_Datatype     btype        = MPI_BYTE;
+    MPI_Datatype     ftype        = MPI_BYTE;
     int              mpi_code;
+    char             unused = 0; /* Unused, except for non-NULL pointer value */
+    size_t           buf_count;
     herr_t           ret_value = SUCCEED;
 
     FUNC_ENTER_STATIC
@@ -908,20 +909,17 @@ H5C__collective_write(H5F_t *f)
     if (H5CX_get_io_xfer_mode(&orig_xfer_mode) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTGET, FAIL, "can't get MPI-I/O transfer mode")
 
+    /* Set transfer mode */
+    if (H5CX_set_io_xfer_mode(H5FD_MPIO_COLLECTIVE) < 0)
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTSET, FAIL, "can't set MPI-I/O transfer mode")
+
     /* Get number of entries in collective write list */
     count = (int)H5SL_count(cache_ptr->coll_write_list);
-
     if (count > 0) {
-        H5FD_mpio_xfer_t   xfer_mode = H5FD_MPIO_COLLECTIVE;
         H5SL_node_t *      node;
         H5C_cache_entry_t *entry_ptr;
-        void *             base_buf;
         int                i;
 
-        /* Set new transfer mode */
-        if (H5CX_set_io_xfer_mode(xfer_mode) < 0)
-            HGOTO_ERROR(H5E_CACHE, H5E_CANTSET, FAIL, "can't set MPI-I/O transfer mode")
-
         /* Allocate arrays */
         if (NULL == (length_array = (int *)H5MM_malloc((size_t)count * sizeof(int))))
             HGOTO_ERROR(H5E_CACHE, H5E_CANTALLOC, FAIL,
@@ -948,7 +946,6 @@ H5C__collective_write(H5F_t *f)
         node = H5SL_next(node);
         i    = 1;
         while (node) {
-
             if (NULL == (entry_ptr = (H5C_cache_entry_t *)H5SL_item(node)))
                 HGOTO_ERROR(H5E_CACHE, H5E_NOTFOUND, FAIL, "can't retrieve skip list item")
 
@@ -966,9 +963,6 @@ H5C__collective_write(H5F_t *f)
         if (MPI_SUCCESS !=
             (mpi_code = MPI_Type_create_hindexed(count, length_array, buf_array, MPI_BYTE, &btype)))
             HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hindexed failed", mpi_code)
-
-        btype_created = TRUE;
-
         if (MPI_SUCCESS != (mpi_code = MPI_Type_commit(&btype)))
             HMPI_GOTO_ERROR(FAIL, "MPI_Type_commit failed", mpi_code)
 
@@ -976,74 +970,27 @@ H5C__collective_write(H5F_t *f)
         if (MPI_SUCCESS !=
             (mpi_code = MPI_Type_create_hindexed(count, length_array, offset_array, MPI_BYTE, &ftype)))
             HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hindexed failed", mpi_code)
-
-        ftype_created = TRUE;
-
         if (MPI_SUCCESS != (mpi_code = MPI_Type_commit(&ftype)))
             HMPI_GOTO_ERROR(FAIL, "MPI_Type_commit failed", mpi_code)
 
-        /* Pass buf type, file type to the file driver */
-        if (H5CX_set_mpi_coll_datatypes(btype, ftype) < 0)
-            HGOTO_ERROR(H5E_CACHE, H5E_CANTSET, FAIL, "can't set MPI-I/O properties")
-
-        /* Write data */
-        /*
-         * At present the page buffer is disabled in the parallel case, and
-         * thus VFD SWMR can't be used either.  Thus, for now, there is
-         * no point in setting the page buffer hints.
-         *
-         * More to the point, since we are actually writing a derived type
-         * containing multiple metadata cache entries, we couldn't set it
-         * to a meaningful value.
-         *
-         * When we enable the page buffer in parallel, we will have to
-         * revisit this.
-         *                                 JRM -- 3/30/20
-         */
-        if (H5F_block_write(f, H5FD_MEM_DEFAULT, (haddr_t)0, (size_t)1, base_buf) < 0)
-            HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "unable to write entries collectively")
-
+        /* MPI count to write */
+        buf_count = 1;
     } /* end if */
     else {
-        MPI_Status mpi_stat;
-        MPI_File * mpi_fh_p;
-        MPI_File   mpi_fh;
-        MPI_Info * info_p;
-        MPI_Info   info;
-
-        /* This should be rewritten to call H5F_block_write, with the correct
-         *      buffer and file datatypes (null ones).  -QAK, 2018/02/21
-         */
-        if (H5F_get_mpi_handle(f, (MPI_File **)&mpi_fh_p) < 0)
-            HGOTO_ERROR(H5E_CACHE, H5E_CANTGET, FAIL, "can't get mpi file handle")
+        /* Set non-NULL pointer for I/O operation */
+        base_buf = &unused;
 
-        mpi_fh = *(MPI_File *)mpi_fh_p;
-
-        if (H5F_get_mpi_info(f, &info_p) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't get mpi file info")
-
-        info = *info_p;
-
-        /* just to match up with the 1st MPI_File_set_view from
-         * H5FD_mpio_write()
-         */
-        if (MPI_SUCCESS !=
-            (mpi_code = MPI_File_set_view(mpi_fh, (MPI_Offset)0, MPI_BYTE, MPI_BYTE, "native", info)))
-            HMPI_GOTO_ERROR(FAIL, "MPI_File_set_view failed", mpi_code)
+        /* MPI count to write */
+        buf_count = 0;
+    } /* end else */
 
-        /* just to match up with MPI_File_write_at_all from H5FD_mpio_write() */
-        HDmemset(&mpi_stat, 0, sizeof(MPI_Status));
-        if (MPI_SUCCESS !=
-            (mpi_code = MPI_File_write_at_all(mpi_fh, (MPI_Offset)0, NULL, 0, MPI_BYTE, &mpi_stat)))
-            HMPI_GOTO_ERROR(FAIL, "MPI_File_write_at_all failed", mpi_code)
+    /* Pass buf type, file type to the file driver */
+    if (H5CX_set_mpi_coll_datatypes(btype, ftype) < 0)
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTSET, FAIL, "can't set MPI-I/O properties")
 
-        /* just to match up with the 2nd MPI_File_set_view (reset) in
-         * H5FD_mpio_write()
-         */
-        if (MPI_SUCCESS !=
-            (mpi_code = MPI_File_set_view(mpi_fh, (MPI_Offset)0, MPI_BYTE, MPI_BYTE, "native", info)))
-            HMPI_GOTO_ERROR(FAIL, "MPI_File_set_view failed", mpi_code)
-    } /* end else */
+    /* Write data */
+    if (H5F_block_write(f, H5FD_MEM_DEFAULT, (haddr_t)0, buf_count, base_buf) < 0)
+        HGOTO_ERROR(H5E_CACHE, H5E_WRITEERROR, FAIL, "unable to write entries collectively")
 
 done:
     /* Free arrays */
@@ -1052,9 +999,9 @@ done:
     offset_array = (MPI_Aint *)H5MM_xfree(offset_array);
 
     /* Free MPI Types */
-    if (btype_created && MPI_SUCCESS != (mpi_code = MPI_Type_free(&btype)))
+    if (MPI_BYTE != btype && MPI_SUCCESS != (mpi_code = MPI_Type_free(&btype)))
         HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code)
-    if (ftype_created && MPI_SUCCESS != (mpi_code = MPI_Type_free(&ftype)))
+    if (MPI_BYTE != ftype && MPI_SUCCESS != (mpi_code = MPI_Type_free(&ftype)))
         HMPI_DONE_ERROR(FAIL, "MPI_Type_free failed", mpi_code)
 
     /* Reset transfer mode in API context, if changed */
diff --git a/src/H5FDmpi.c b/src/H5FDmpi.c
index 32c899d..048b8f3 100644
--- a/src/H5FDmpi.c
+++ b/src/H5FDmpi.c
@@ -136,43 +136,6 @@ done:
 } /* end H5FD_mpi_get_comm() */
 
 /*-------------------------------------------------------------------------
- * Function:	H5FD_get_mpi_info
- *
- * Purpose:	Retrieves the file's mpi info
- *
- * Return:	Success:	SUCCEED
- *
- *		Failure:	FAIL
- *
- * Programmer:	John Mainzer
- *              4/4/17
- *
- * Modifications:
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5FD_get_mpi_info(H5FD_t *file, void **mpi_info)
-{
-    const H5FD_class_mpi_t *cls;
-    herr_t                  ret_value = SUCCEED;
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    HDassert(file);
-    cls = (const H5FD_class_mpi_t *)(file->cls);
-    HDassert(cls);
-    HDassert(cls->get_mpi_info); /* All MPI drivers must implement this */
-
-    /* Dispatch to driver */
-    if ((ret_value = (cls->get_mpi_info)(file, mpi_info)) < 0)
-        HGOTO_ERROR(H5E_VFL, H5E_CANTGET, FAIL, "driver get_mpi_info request failed")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FD_get_mpi_info() */
-
-/*-------------------------------------------------------------------------
  * Function:    H5FD_mpi_MPIOff_to_haddr
  *
  * Purpose:     Convert an MPI_Offset value to haddr_t.
diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index b8bfae8..9dbd443 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -42,7 +42,7 @@
 static hid_t H5FD_MPIO_g = 0;
 
 /* Whether to allow collective I/O operations */
-/* (Value can be set from environment variable also) */
+/* (Can be changed by setting "HDF5_MPI_OPT_TYPES" environment variable to '0' or '1') */
 hbool_t H5FD_mpi_opt_types_g = TRUE;
 
 /*
@@ -89,7 +89,6 @@ static herr_t   H5FD__mpio_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closin
 static int      H5FD__mpio_mpi_rank(const H5FD_t *_file);
 static int      H5FD__mpio_mpi_size(const H5FD_t *_file);
 static MPI_Comm H5FD__mpio_communicator(const H5FD_t *_file);
-static herr_t   H5FD__mpio_get_info(H5FD_t *_file, void **mpi_info);
 
 /* The MPIO file driver information */
 static const H5FD_class_mpi_t H5FD_mpio_g = {
@@ -131,28 +130,30 @@ static const H5FD_class_mpi_t H5FD_mpio_g = {
     },                         /* End of superclass information */
     H5FD__mpio_mpi_rank,       /*get_rank              */
     H5FD__mpio_mpi_size,       /*get_size              */
-    H5FD__mpio_communicator,   /*get_comm              */
-    H5FD__mpio_get_info        /*get_info              */
+    H5FD__mpio_communicator    /*get_comm              */
 };
 
 #ifdef H5FDmpio_DEBUG
-/* Flags to control debug actions in H5Fmpio.
- * Meant to be indexed by characters.
- *
- * 'c' show result of MPI_Get_count after read
- * 'r' show read offset and size
- * 't' trace function entry and exit
- * 'w' show write offset and size
+/* Flags to control debug actions in the MPI-IO VFD.
+ * (Meant to be indexed by characters)
+ *
+ * These flags can be set with either (or both) the environment variable
+ *      "H5FD_mpio_Debug" set to a string containing one or more characters
+ *      (flags) or by setting them as a string value for the
+ *      "H5F_mpio_debug_key" MPI Info key.
+ *
+ * Supported characters in 'H5FD_mpio_Debug' string:
+ *      't' trace function entry and exit
+ *      'r' show read offset and size
+ *      'w' show write offset and size
+ *      '0'-'9' only show output from a single MPI rank (ranks 0-9 supported)
  */
-static int H5FD_mpio_Debug[256] = {
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+static int H5FD_mpio_debug_flags_s[256];
+static int H5FD_mpio_debug_rank_s = -1;
+
+/* Indicate if this rank should output tracing info */
+#define H5FD_MPIO_TRACE_THIS_RANK(file)                                                                      \
+    (H5FD_mpio_debug_rank_s < 0 || H5FD_mpio_debug_rank_s == (file)->mpi_rank)
 #endif
 
 /*--------------------------------------------------------------------------
@@ -184,6 +185,41 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5FD__init_package() */
 
+#ifdef H5FDmpio_DEBUG
+
+/*---------------------------------------------------------------------------
+ * Function:    H5FD__mpio_parse_debug_str
+ *
+ * Purpose:     Parse a string for debugging flags
+ *
+ * Returns:     N/A
+ *
+ * Programmer:  Quincey Koziol
+ *              Wednesday, Aug 12, 2020
+ *
+ *---------------------------------------------------------------------------
+ */
+static void
+H5FD__mpio_parse_debug_str(const char *s)
+{
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity check */
+    HDassert(s);
+
+    /* Set debug mask */
+    while (*s) {
+        if ((int)(*s) >= (int)'0' && (int)(*s) <= (int)'9')
+            H5FD_mpio_debug_rank_s = ((int)*s) - (int)'0';
+        else
+            H5FD_mpio_debug_flags_s[(int)*s]++;
+        s++;
+    } /* end while */
+
+    FUNC_LEAVE_NOAPI_VOID
+} /* end H5FD__mpio_parse_debug_str() */
+#endif /* H5FDmpio_DEBUG */
+
 /*-------------------------------------------------------------------------
  * Function:    H5FD_mpio_init
  *
@@ -201,11 +237,8 @@ done:
 hid_t
 H5FD_mpio_init(void)
 {
-#ifdef H5FDmpio_DEBUG
     static int H5FD_mpio_Debug_inited = 0;
-#endif                                       /* H5FDmpio_DEBUG */
-    const char *s;                           /* String for environment variables */
-    hid_t       ret_value = H5I_INVALID_HID; /* Return value */
+    hid_t      ret_value              = H5I_INVALID_HID; /* Return value */
 
     FUNC_ENTER_NOAPI(H5I_INVALID_HID)
 
@@ -213,28 +246,27 @@ H5FD_mpio_init(void)
     if (H5I_VFL != H5I_get_type(H5FD_MPIO_g))
         H5FD_MPIO_g = H5FD_register((const H5FD_class_t *)&H5FD_mpio_g, sizeof(H5FD_class_mpi_t), FALSE);
 
-    /* Allow MPI buf-and-file-type optimizations? */
-    s = HDgetenv("HDF5_MPI_OPT_TYPES");
-    if (s && HDisdigit(*s)) {
-        long env_val         = HDstrtol(s, NULL, 0);
-        H5FD_mpi_opt_types_g = (0 == env_val) ? FALSE : TRUE;
-    }
+    if (!H5FD_mpio_Debug_inited) {
+        const char *s; /* String for environment variables */
+
+        /* Allow MPI buf-and-file-type optimizations? */
+        s = HDgetenv("HDF5_MPI_OPT_TYPES");
+        if (s && HDisdigit(*s))
+            H5FD_mpi_opt_types_g = (0 == HDstrtol(s, NULL, 0)) ? FALSE : TRUE;
 
 #ifdef H5FDmpio_DEBUG
-    if (!H5FD_mpio_Debug_inited) {
+        /* Clear the flag buffer */
+        HDmemset(H5FD_mpio_debug_flags_s, 0, sizeof(H5FD_mpio_debug_flags_s));
+
         /* Retrieve MPI-IO debugging environment variable */
         s = HDgetenv("H5FD_mpio_Debug");
-        if (s) {
-            /* Set debug mask */
-            while (*s) {
-                H5FD_mpio_Debug[(int)*s]++;
-                s++;
-            } /* end while */
-        }     /* end if */
-        H5FD_mpio_Debug_inited++;
-    }  /* end if */
+        if (s)
+            H5FD__mpio_parse_debug_str(s);
 #endif /* H5FDmpio_DEBUG */
 
+        H5FD_mpio_Debug_inited++;
+    } /* end if */
+
     /* Set return value */
     ret_value = H5FD_MPIO_g;
 
@@ -658,30 +690,27 @@ herr_t
 H5FD_set_mpio_atomicity(H5FD_t *_file, hbool_t flag)
 {
     H5FD_mpio_t *file = (H5FD_mpio_t *)_file;
-    int          mpi_code; /* MPI return code */
-    int          temp_flag;
-    herr_t       ret_value = SUCCEED;
+#ifdef H5FDmpio_DEBUG
+    hbool_t H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+#endif
+    int    mpi_code; /* MPI return code */
+    herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Entering\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Entering\n", FUNC, file->mpi_rank);
 #endif
 
-    if (FALSE == flag)
-        temp_flag = 0;
-    else
-        temp_flag = 1;
-
     /* set atomicity value */
-    if (MPI_SUCCESS != (mpi_code = MPI_File_set_atomicity(file->f, temp_flag)))
+    if (MPI_SUCCESS != (mpi_code = MPI_File_set_atomicity(file->f, (int)(flag != FALSE))))
         HMPI_GOTO_ERROR(FAIL, "MPI_File_set_atomicity", mpi_code)
 
 done:
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Leaving\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Leaving\n", FUNC, file->mpi_rank);
 #endif
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -703,15 +732,18 @@ herr_t
 H5FD_get_mpio_atomicity(H5FD_t *_file, hbool_t *flag)
 {
     H5FD_mpio_t *file = (H5FD_mpio_t *)_file;
-    int          mpi_code; /* MPI return code */
     int          temp_flag;
-    herr_t       ret_value = SUCCEED;
+#ifdef H5FDmpio_DEBUG
+    hbool_t H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+#endif
+    int    mpi_code; /* MPI return code */
+    herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Entering\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Entering\n", FUNC, file->mpi_rank);
 #endif
 
     /* Get atomicity value */
@@ -725,8 +757,8 @@ H5FD_get_mpio_atomicity(H5FD_t *_file, hbool_t *flag)
 
 done:
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Leaving\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Leaving\n", FUNC, file->mpi_rank);
 #endif
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -753,26 +785,23 @@ done:
 static H5FD_t *
 H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t H5_ATTR_UNUSED maxaddr)
 {
-    H5FD_mpio_t *   file = NULL;
-    MPI_File        fh;
-    hbool_t         file_opened = FALSE; /* Flag to indicate that the file was successfully opened */
-    int             mpi_amode;
-    int             mpi_rank; /* MPI rank of this process */
-    int             mpi_size; /* Total number of MPI processes */
-    int             mpi_code; /* MPI return code */
-    MPI_Offset      size;
-    H5P_genplist_t *plist; /* Property list pointer */
-    MPI_Comm        comm      = MPI_COMM_NULL;
-    MPI_Info        info      = MPI_INFO_NULL;
-    H5FD_t *        ret_value = NULL; /* Return value */
-
-    FUNC_ENTER_STATIC
-
+    H5FD_mpio_t *   file = NULL;          /* VFD File struct for new file */
+    H5P_genplist_t *plist;                /* Property list pointer */
+    MPI_Comm        comm = MPI_COMM_NULL; /* MPI Communicator, from plist */
+    MPI_Info        info = MPI_INFO_NULL; /* MPI Info, from plist */
+    MPI_File        fh;                   /* MPI file handle */
+    hbool_t         file_opened = FALSE;  /* Flag to indicate that the file was successfully opened */
+    int             mpi_amode;            /* MPI file access flags */
+    int             mpi_rank = INT_MAX;   /* MPI rank of this process */
+    int             mpi_size;             /* Total number of MPI processes */
+    MPI_Offset      file_size;            /* File size (of existing files) */
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Entering - name = \"%s\", flags = 0x%x, fapl_id = %d, maxaddr = %lu\n", FUNC,
-                  name, flags, (int)fapl_id, (unsigned long)maxaddr);
+    hbool_t H5FD_mpio_debug_t_flag = FALSE;
 #endif
+    int     mpi_code;         /* MPI return code */
+    H5FD_t *ret_value = NULL; /* Return value */
+
+    FUNC_ENTER_STATIC
 
     /* Get a pointer to the fapl */
     if (NULL == (plist = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
@@ -784,6 +813,20 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t H5_ATTR
     if (H5P_get(plist, H5F_ACS_MPI_PARAMS_INFO_NAME, &info) < 0)
         HGOTO_ERROR(H5E_VFL, H5E_CANTGET, NULL, "can't get MPI info object")
 
+    /* Get the MPI rank of this process and the total number of processes */
+    if (MPI_SUCCESS != (mpi_code = MPI_Comm_rank(comm, &mpi_rank)))
+        HMPI_GOTO_ERROR(NULL, "MPI_Comm_rank failed", mpi_code)
+    if (MPI_SUCCESS != (mpi_code = MPI_Comm_size(comm, &mpi_size)))
+        HMPI_GOTO_ERROR(NULL, "MPI_Comm_size failed", mpi_code)
+
+#ifdef H5FDmpio_DEBUG
+    H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] &&
+                              (H5FD_mpio_debug_rank_s < 0 || H5FD_mpio_debug_rank_s == mpi_rank));
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Entering - name = \"%s\", flags = 0x%x, fapl_id = %d, maxaddr = %lu\n",
+                  FUNC, mpi_rank, name, flags, (int)fapl_id, (unsigned long)maxaddr);
+#endif
+
     /* Convert HDF5 flags to MPI-IO flags */
     /* Some combinations are illegal; let MPI-IO figure it out */
     mpi_amode = (flags & H5F_ACC_RDWR) ? MPI_MODE_RDWR : MPI_MODE_RDONLY;
@@ -799,26 +842,15 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t H5_ATTR
         int  flag;
 
         MPI_Info_get(info, H5F_MPIO_DEBUG_KEY, sizeof(debug_str) - 1, debug_str, &flag);
-        if (flag) {
-            int i;
-
-            HDfprintf(stdout, "H5FD_mpio debug flags = '%s'\n", debug_str);
-            for (i = 0; debug_str[i] /*end of string*/ && i < 128 /*just in case*/; ++i)
-                H5FD_mpio_Debug[(int)debug_str[i]] = 1;
-        } /* end if */
-    }     /* end if */
+        if (flag)
+            H5FD__mpio_parse_debug_str(debug_str);
+    } /* end if */
 #endif
 
     if (MPI_SUCCESS != (mpi_code = MPI_File_open(comm, name, mpi_amode, info, &fh)))
         HMPI_GOTO_ERROR(NULL, "MPI_File_open failed", mpi_code)
     file_opened = TRUE;
 
-    /* Get the MPI rank of this process and the total number of processes */
-    if (MPI_SUCCESS != (mpi_code = MPI_Comm_rank(comm, &mpi_rank)))
-        HMPI_GOTO_ERROR(NULL, "MPI_Comm_rank failed", mpi_code)
-    if (MPI_SUCCESS != (mpi_code = MPI_Comm_size(comm, &mpi_size)))
-        HMPI_GOTO_ERROR(NULL, "MPI_Comm_size failed", mpi_code)
-
     /* Build the return value and initialize it */
     if (NULL == (file = (H5FD_mpio_t *)H5MM_calloc(sizeof(H5FD_mpio_t))))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
@@ -829,17 +861,17 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t H5_ATTR
     file->mpi_size = mpi_size;
 
     /* Only processor p0 will get the filesize and broadcast it. */
-    if (mpi_rank == 0) {
-        if (MPI_SUCCESS != (mpi_code = MPI_File_get_size(fh, &size)))
+    if (mpi_rank == 0)
+        if (MPI_SUCCESS != (mpi_code = MPI_File_get_size(fh, &file_size)))
             HMPI_GOTO_ERROR(NULL, "MPI_File_get_size failed", mpi_code)
-    } /* end if */
 
     /* Broadcast file size */
-    if (MPI_SUCCESS != (mpi_code = MPI_Bcast(&size, (int)sizeof(MPI_Offset), MPI_BYTE, 0, comm)))
+    if (MPI_SUCCESS != (mpi_code = MPI_Bcast(&file_size, (int)sizeof(MPI_Offset), MPI_BYTE, 0, comm)))
         HMPI_GOTO_ERROR(NULL, "MPI_Bcast failed", mpi_code)
 
     /* Determine if the file should be truncated */
-    if (size && (flags & H5F_ACC_TRUNC)) {
+    if (file_size && (flags & H5F_ACC_TRUNC)) {
+        /* Truncate the file */
         if (MPI_SUCCESS != (mpi_code = MPI_File_set_size(fh, (MPI_Offset)0)))
             HMPI_GOTO_ERROR(NULL, "MPI_File_set_size failed", mpi_code)
 
@@ -848,11 +880,11 @@ H5FD__mpio_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t H5_ATTR
             HMPI_GOTO_ERROR(NULL, "MPI_Barrier failed", mpi_code)
 
         /* File is zero size now */
-        size = 0;
+        file_size = 0;
     } /* end if */
 
     /* Set the size of the file (from library's perspective) */
-    file->eof       = H5FD_mpi_MPIOff_to_haddr(size);
+    file->eof       = H5FD_mpi_MPIOff_to_haddr(file_size);
     file->local_eof = file->eof;
 
     /* Set return value */
@@ -871,8 +903,8 @@ done:
     } /* end if */
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Leaving\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Leaving\n", FUNC, mpi_rank);
 #endif
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -894,14 +926,18 @@ static herr_t
 H5FD__mpio_close(H5FD_t *_file)
 {
     H5FD_mpio_t *file = (H5FD_mpio_t *)_file;
-    int          mpi_code;            /* MPI return code */
-    herr_t       ret_value = SUCCEED; /* Return value */
+#ifdef H5FDmpio_DEBUG
+    hbool_t H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+    int     mpi_rank               = file->mpi_rank;
+#endif
+    int    mpi_code;            /* MPI return code */
+    herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_STATIC
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Entering\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Entering\n", FUNC, file->mpi_rank);
 #endif
 
     /* Sanity checks */
@@ -909,7 +945,7 @@ H5FD__mpio_close(H5FD_t *_file)
     HDassert(H5FD_MPIO == file->pub.driver_id);
 
     /* MPI_File_close sets argument to MPI_FILE_NULL */
-    if (MPI_SUCCESS != (mpi_code = MPI_File_close(&(file->f) /*in,out*/)))
+    if (MPI_SUCCESS != (mpi_code = MPI_File_close(&(file->f))))
         HMPI_GOTO_ERROR(FAIL, "MPI_File_close failed", mpi_code)
 
     /* Clean up other stuff */
@@ -919,8 +955,8 @@ H5FD__mpio_close(H5FD_t *_file)
 
 done:
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Leaving\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Leaving\n", FUNC, mpi_rank);
 #endif
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -952,7 +988,7 @@ H5FD__mpio_query(const H5FD_t H5_ATTR_UNUSED *_file, unsigned long *flags /* out
         *flags |= H5FD_FEAT_HAS_MPI; /* This driver uses MPI                                             */
         *flags |= H5FD_FEAT_ALLOCATE_EARLY;         /* Allocate space early instead of late         */
         *flags |= H5FD_FEAT_DEFAULT_VFD_COMPATIBLE; /* VFD creates a file which can be opened with the default
-                                                       VFD      */
+                                                       VFD */
     }                                               /* end if */
 
     FUNC_LEAVE_NOAPI(SUCCEED)
@@ -1114,7 +1150,6 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
     H5FD_mpio_t *file = (H5FD_mpio_t *)_file;
     MPI_Offset   mpi_off;
     MPI_Status   mpi_stat;            /* Status from I/O operation */
-    int          mpi_code;            /* mpi return code */
     MPI_Datatype buf_type = MPI_BYTE; /* MPI description of the selection in memory */
     int          size_i;              /* Integer copy of 'size' to read */
 #if MPI_VERSION >= 3
@@ -1130,13 +1165,18 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
 #endif
     hbool_t use_view_this_time = FALSE;
     hbool_t rank0_bcast        = FALSE; /* If read-with-rank0-and-bcast flag was used */
-    herr_t  ret_value          = SUCCEED;
+#ifdef H5FDmpio_DEBUG
+    hbool_t H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+    hbool_t H5FD_mpio_debug_r_flag = (H5FD_mpio_debug_flags_s[(int)'r'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+#endif
+    int    mpi_code; /* MPI return code */
+    herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_STATIC
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Entering\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Entering\n", FUNC, file->mpi_rank);
 #endif
 
     /* Sanity checks */
@@ -1155,8 +1195,9 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
         HGOTO_ERROR(H5E_INTERNAL, H5E_BADRANGE, FAIL, "can't convert from size to size_i")
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'r'])
-        HDfprintf(stdout, "%s: mpi_off = %ld  size_i = %d\n", FUNC, (long)mpi_off, size_i);
+    if (H5FD_mpio_debug_r_flag)
+        HDfprintf(stderr, "%s: (%d) mpi_off = %ld  size_i = %d\n", FUNC, file->mpi_rank, (long)mpi_off,
+                  size_i);
 #endif
 
     /* Only look for MPI views for raw data transfers */
@@ -1202,8 +1243,8 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
         H5FD_mpio_collective_opt_t coll_opt_mode;
 
 #ifdef H5FDmpio_DEBUG
-        if (H5FD_mpio_Debug[(int)'r'])
-            HDfprintf(stdout, "%s: using MPIO collective mode\n", FUNC);
+        if (H5FD_mpio_debug_r_flag)
+            HDfprintf(stderr, "%s: (%d) using MPIO collective mode\n", FUNC, file->mpi_rank);
 #endif
         /* Get the collective_opt property to check whether the application wants to do IO individually. */
         if (H5CX_get_mpio_coll_opt(&coll_opt_mode) < 0)
@@ -1211,14 +1252,14 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
 
         if (coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO) {
 #ifdef H5FDmpio_DEBUG
-            if (H5FD_mpio_Debug[(int)'r'])
-                HDfprintf(stdout, "%s: doing MPI collective IO\n", FUNC);
+            if (H5FD_mpio_debug_r_flag)
+                HDfprintf(stderr, "%s: (%d) doing MPI collective IO\n", FUNC, file->mpi_rank);
 #endif
             /* Check whether we should read from rank 0 and broadcast to other ranks */
             if (H5CX_get_mpio_rank0_bcast()) {
 #ifdef H5FDmpio_DEBUG
-                if (H5FD_mpio_Debug[(int)'r'])
-                    HDfprintf(stdout, "%s: doing read-rank0-and-MPI_Bcast\n", FUNC);
+                if (H5FD_mpio_debug_r_flag)
+                    HDfprintf(stderr, "%s: (%d) doing read-rank0-and-MPI_Bcast\n", FUNC, file->mpi_rank);
 #endif
                 /* Indicate path we've taken */
                 rank0_bcast = TRUE;
@@ -1231,16 +1272,19 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
                 if (MPI_SUCCESS != (mpi_code = MPI_Bcast(buf, size_i, buf_type, 0, file->comm)))
                     HMPI_GOTO_ERROR(FAIL, "MPI_Bcast failed", mpi_code)
             } /* end if */
-            else if (MPI_SUCCESS !=
-                     (mpi_code = MPI_File_read_at_all(file->f, mpi_off, buf, size_i, buf_type, &mpi_stat)))
+            else
+                /* Perform collective read operation */
+                if (MPI_SUCCESS !=
+                    (mpi_code = MPI_File_read_at_all(file->f, mpi_off, buf, size_i, buf_type, &mpi_stat)))
                 HMPI_GOTO_ERROR(FAIL, "MPI_File_read_at_all failed", mpi_code)
         } /* end if */
         else {
 #ifdef H5FDmpio_DEBUG
-            if (H5FD_mpio_Debug[(int)'r'])
-                HDfprintf(stdout, "%s: doing MPI independent IO\n", FUNC);
+            if (H5FD_mpio_debug_r_flag)
+                HDfprintf(stderr, "%s: (%d) doing MPI independent IO\n", FUNC, file->mpi_rank);
 #endif
 
+            /* Perform independent read operation */
             if (MPI_SUCCESS !=
                 (mpi_code = MPI_File_read_at(file->f, mpi_off, buf, size_i, buf_type, &mpi_stat)))
                 HMPI_GOTO_ERROR(FAIL, "MPI_File_read_at failed", mpi_code)
@@ -1253,8 +1297,16 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
                                                          H5FD_mpi_native_g, file->info)))
             HMPI_GOTO_ERROR(FAIL, "MPI_File_set_view failed", mpi_code)
     } /* end if */
-    else if (MPI_SUCCESS != (mpi_code = MPI_File_read_at(file->f, mpi_off, buf, size_i, buf_type, &mpi_stat)))
-        HMPI_GOTO_ERROR(FAIL, "MPI_File_read_at failed", mpi_code)
+    else {
+#ifdef H5FDmpio_DEBUG
+        if (H5FD_mpio_debug_r_flag)
+            HDfprintf(stderr, "%s: (%d) doing MPI independent IO\n", FUNC, file->mpi_rank);
+#endif
+
+        /* Perform independent read operation */
+        if (MPI_SUCCESS != (mpi_code = MPI_File_read_at(file->f, mpi_off, buf, size_i, buf_type, &mpi_stat)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_File_read_at failed", mpi_code)
+    } /* end else */
 
     /* Only retrieve bytes read if this rank _actually_ participated in I/O */
     if (!rank0_bcast || (rank0_bcast && file->mpi_rank == 0)) {
@@ -1274,7 +1326,11 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
      *          of the data.  (QAK - 2019/1/2)
      */
     if (rank0_bcast)
-        if (MPI_SUCCESS != MPI_Bcast(&bytes_read, 1, MPI_LONG_LONG, 0, file->comm))
+#if MPI_VERSION >= 3
+        if (MPI_SUCCESS != MPI_Bcast(&bytes_read, 1, MPI_COUNT, 0, file->comm))
+#else
+        if (MPI_SUCCESS != MPI_Bcast(&bytes_read, 1, MPI_INT, 0, file->comm))
+#endif
             HMPI_GOTO_ERROR(FAIL, "MPI_Bcast failed", 0)
 
             /* Get the type's size */
@@ -1300,8 +1356,8 @@ H5FD__mpio_read(H5FD_t *_file, H5FD_mem_t H5_ATTR_UNUSED type, hid_t H5_ATTR_UNU
 
 done:
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Leaving\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Leaving\n", FUNC, file->mpi_rank);
 #endif
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1336,7 +1392,6 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
     MPI_Offset   mpi_off;
     MPI_Status   mpi_stat;            /* Status from I/O operation */
     MPI_Datatype buf_type = MPI_BYTE; /* MPI description of the selection in memory */
-    int          mpi_code;            /* MPI return code */
 #if MPI_VERSION >= 3
     MPI_Count bytes_written;
     MPI_Count type_size; /* MPI datatype used for I/O's size */
@@ -1350,13 +1405,18 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
     hbool_t          use_view_this_time = FALSE;
     hbool_t          derived_type       = FALSE;
     H5FD_mpio_xfer_t xfer_mode; /* I/O transfer mode */
-    herr_t           ret_value = SUCCEED;
+#ifdef H5FDmpio_DEBUG
+    hbool_t H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+    hbool_t H5FD_mpio_debug_w_flag = (H5FD_mpio_debug_flags_s[(int)'w'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+#endif
+    int    mpi_code; /* MPI return code */
+    herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_STATIC
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Entering\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Entering\n", FUNC, file->mpi_rank);
 #endif
 
     /* Sanity checks */
@@ -1376,8 +1436,9 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
     size_i = (int)size;
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'w'])
-        HDfprintf(stdout, "%s: mpi_off = %ld  size_i = %d\n", FUNC, (long)mpi_off, size_i);
+    if (H5FD_mpio_debug_w_flag)
+        HDfprintf(stderr, "%s: (%d) mpi_off = %ld  size_i = %d\n", FUNC, file->mpi_rank, (long)mpi_off,
+                  size_i);
 #endif
 
     /* Get the transfer mode from the API context */
@@ -1432,8 +1493,8 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
         H5FD_mpio_collective_opt_t coll_opt_mode;
 
 #ifdef H5FDmpio_DEBUG
-        if (H5FD_mpio_Debug[(int)'w'])
-            HDfprintf(stdout, "%s: using MPIO collective mode\n", FUNC);
+        if (H5FD_mpio_debug_w_flag)
+            HDfprintf(stderr, "%s: (%d) using MPIO collective mode\n", FUNC, file->mpi_rank);
 #endif
 
         /* Get the collective_opt property to check whether the application wants to do IO individually. */
@@ -1442,8 +1503,8 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
 
         if (coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO) {
 #ifdef H5FDmpio_DEBUG
-            if (H5FD_mpio_Debug[(int)'w'])
-                HDfprintf(stdout, "%s: doing MPI collective IO\n", FUNC);
+            if (H5FD_mpio_debug_w_flag)
+                HDfprintf(stderr, "%s: (%d) doing MPI collective IO\n", FUNC, file->mpi_rank);
 #endif
             /* Perform collective write operation */
             if (MPI_SUCCESS !=
@@ -1454,9 +1515,10 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
             if (type != H5FD_MEM_DRAW)
                 HGOTO_ERROR(H5E_PLIST, H5E_BADTYPE, FAIL,
                             "Metadata Coll opt property should be collective at this point")
+
 #ifdef H5FDmpio_DEBUG
-            if (H5FD_mpio_Debug[(int)'w'])
-                HDfprintf(stdout, "%s: doing MPI independent IO\n", FUNC);
+            if (H5FD_mpio_debug_w_flag)
+                HDfprintf(stderr, "%s: (%d) doing MPI independent IO\n", FUNC, file->mpi_rank);
 #endif
             /* Perform independent write operation */
             if (MPI_SUCCESS !=
@@ -1469,11 +1531,18 @@ H5FD__mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, h
                                                          H5FD_mpi_native_g, file->info)))
             HMPI_GOTO_ERROR(FAIL, "MPI_File_set_view failed", mpi_code)
     } /* end if */
-    else if (MPI_SUCCESS !=
-             (mpi_code = MPI_File_write_at(file->f, mpi_off, buf, size_i, buf_type, &mpi_stat)))
-        HMPI_GOTO_ERROR(FAIL, "MPI_File_write_at failed", mpi_code)
+    else {
+#ifdef H5FDmpio_DEBUG
+        if (H5FD_mpio_debug_w_flag)
+            HDfprintf(stderr, "%s: (%d) doing MPI independent IO\n", FUNC, file->mpi_rank);
+#endif
 
-        /* How many bytes were actually written? */
+        /* Perform independent write operation */
+        if (MPI_SUCCESS != (mpi_code = MPI_File_write_at(file->f, mpi_off, buf, size_i, buf_type, &mpi_stat)))
+            HMPI_GOTO_ERROR(FAIL, "MPI_File_write_at failed", mpi_code)
+    } /* end else */
+
+    /* How many bytes were actually written? */
 #if MPI_VERSION >= 3
     if (MPI_SUCCESS != (mpi_code = MPI_Get_elements_x(&mpi_stat, buf_type, &bytes_written)))
 #else
@@ -1512,8 +1581,8 @@ done:
         MPI_Type_free(&buf_type);
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Leaving, proc %d: ret_value = %d\n", FUNC, file->mpi_rank, ret_value);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Leaving: ret_value = %d\n", FUNC, file->mpi_rank, ret_value);
 #endif
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1535,14 +1604,17 @@ static herr_t
 H5FD__mpio_flush(H5FD_t *_file, hid_t H5_ATTR_UNUSED dxpl_id, hbool_t closing)
 {
     H5FD_mpio_t *file = (H5FD_mpio_t *)_file;
-    int          mpi_code; /* mpi return code */
-    herr_t       ret_value = SUCCEED;
+#ifdef H5FDmpio_DEBUG
+    hbool_t H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+#endif
+    int    mpi_code; /* mpi return code */
+    herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_STATIC
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Entering\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Entering\n", FUNC, file->mpi_rank);
 #endif
 
     /* Sanity checks */
@@ -1556,8 +1628,8 @@ H5FD__mpio_flush(H5FD_t *_file, hid_t H5_ATTR_UNUSED dxpl_id, hbool_t closing)
 
 done:
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Leaving\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Leaving\n", FUNC, file->mpi_rank);
 #endif
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1570,13 +1642,14 @@ done:
  *
  *              This is a little sticky in the mpio case, as it is not
  *              easy for us to track the current EOF by extracting it from
- *              write calls.
+ *              write calls, since other ranks could have written to the
+ *              file beyond the local EOF.
  *
- *              Instead, we first check to see if the eoa has changed since
+ *              Instead, we first check to see if the EOA has changed since
  *              the last call to this function.  If it has, we call
  *              MPI_File_get_size() to determine the current EOF, and
  *              only call MPI_File_set_size() if this value disagrees
- *              with the current eoa.
+ *              with the current EOA.
  *
  * Return:      SUCCEED/FAIL
  *
@@ -1588,14 +1661,17 @@ done:
 static herr_t
 H5FD__mpio_truncate(H5FD_t *_file, hid_t H5_ATTR_UNUSED dxpl_id, hbool_t H5_ATTR_UNUSED closing)
 {
-    H5FD_mpio_t *file      = (H5FD_mpio_t *)_file;
-    herr_t       ret_value = SUCCEED;
+    H5FD_mpio_t *file = (H5FD_mpio_t *)_file;
+#ifdef H5FDmpio_DEBUG
+    hbool_t H5FD_mpio_debug_t_flag = (H5FD_mpio_debug_flags_s[(int)'t'] && H5FD_MPIO_TRACE_THIS_RANK(file));
+#endif
+    herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_STATIC
 
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Entering\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Entering\n", FUNC, file->mpi_rank);
 #endif
 
     /* Sanity checks */
@@ -1663,8 +1739,8 @@ H5FD__mpio_truncate(H5FD_t *_file, hid_t H5_ATTR_UNUSED dxpl_id, hbool_t H5_ATTR
 
 done:
 #ifdef H5FDmpio_DEBUG
-    if (H5FD_mpio_Debug[(int)'t'])
-        HDfprintf(stdout, "%s: Leaving\n", FUNC);
+    if (H5FD_mpio_debug_t_flag)
+        HDfprintf(stderr, "%s: (%d) Leaving\n", FUNC, file->mpi_rank);
 #endif
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1750,34 +1826,4 @@ H5FD__mpio_communicator(const H5FD_t *_file)
 
     FUNC_LEAVE_NOAPI(file->comm)
 } /* end H5FD__mpio_communicator() */
-
-/*-------------------------------------------------------------------------
- * Function:       H5FD__mpio_get_info
- *
- * Purpose:        Returns the file info of MPIO file driver.
- *
- * Returns:        Non-negative if succeed or negative if fails.
- *
- * Programmer:     John Mainzer
- *                 April 4, 2017
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5FD__mpio_get_info(H5FD_t *_file, void **mpi_info)
-{
-    H5FD_mpio_t *file      = (H5FD_mpio_t *)_file;
-    herr_t       ret_value = SUCCEED;
-
-    FUNC_ENTER_STATIC
-
-    if (!mpi_info)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "mpi info not valid")
-
-    *mpi_info = &(file->info);
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5FD__mpio_get_info() */
-
 #endif /* H5_HAVE_PARALLEL */
diff --git a/src/H5FDprivate.h b/src/H5FDprivate.h
index 1e405d2..adf900a 100644
--- a/src/H5FDprivate.h
+++ b/src/H5FDprivate.h
@@ -22,13 +22,13 @@
 #include "H5FDpublic.h"
 
 /* Private headers needed by this file */
-#include "H5Pprivate.h" /* Property lists			*/
+#include "H5Pprivate.h" /* Property lists            */
 
 /*
  * The MPI drivers are needed because there are
  * places where we check for things that aren't handled by these drivers.
  */
-#include "H5FDmpi.h" /* MPI-based file drivers		*/
+#include "H5FDmpi.h" /* MPI-based file drivers        */
 
 /**************************/
 /* Library Private Macros */
@@ -260,11 +260,10 @@ vfd_swmr_pageno_to_mdf_idx_entry(H5FD_vfd_swmr_idx_entry_t *idx, uint32_t nentri
 
 /* Sub-class the H5FD_class_t to add more specific functions for MPI-based VFDs */
 typedef struct H5FD_class_mpi_t {
-    H5FD_class_t super;                                    /* Superclass information & methods */
-    int (*get_rank)(const H5FD_t *file);                   /* Get the MPI rank of a process */
-    int (*get_size)(const H5FD_t *file);                   /* Get the MPI size of a communicator */
-    MPI_Comm (*get_comm)(const H5FD_t *file);              /* Get the communicator for a file */
-    herr_t (*get_mpi_info)(H5FD_t *file, void **mpi_info); /* get MPI_Info for a file */
+    H5FD_class_t super;                       /* Superclass information & methods */
+    int (*get_rank)(const H5FD_t *file);      /* Get the MPI rank of a process */
+    int (*get_size)(const H5FD_t *file);      /* Get the MPI size of a communicator */
+    MPI_Comm (*get_comm)(const H5FD_t *file); /* Get the communicator for a file */
 } H5FD_class_mpi_t;
 #endif
 
@@ -289,10 +288,16 @@ typedef struct {
 /* Define default file image info */
 #define H5FD_DEFAULT_FILE_IMAGE_INFO                                                                         \
     {                                                                                                        \
-        /* file image buffer */ NULL, /* buffer size */ 0,                                                   \
-        { /* Callbacks */                                                                                    \
-            /* image_malloc */ NULL, /* image_memcpy */ NULL, /* image_realloc */ NULL,                      \
-                /* image_free */ NULL, /* udata_copy */ NULL, /* udata_free */ NULL, /* udata */ NULL,       \
+        NULL,         /* file image buffer */                                                                \
+            0,        /* buffer size */                                                                      \
+        {             /* Callbacks */                                                                        \
+            NULL,     /* image_malloc */                                                                     \
+                NULL, /* image_memcpy */                                                                     \
+                NULL, /* image_realloc */                                                                    \
+                NULL, /* image_free */                                                                       \
+                NULL, /* udata_copy */                                                                       \
+                NULL, /* udata_free */                                                                       \
+                NULL, /* udata */                                                                            \
         }                                                                                                    \
     }
 
@@ -377,7 +382,6 @@ H5_DLL herr_t H5FD_get_mpio_atomicity(H5FD_t *file, hbool_t *flag);
 H5_DLL int      H5FD_mpi_get_rank(const H5FD_t *file);
 H5_DLL int      H5FD_mpi_get_size(const H5FD_t *file);
 H5_DLL MPI_Comm H5FD_mpi_get_comm(const H5FD_t *_file);
-H5_DLL herr_t   H5FD_get_mpi_info(H5FD_t *file, void **file_info);
 #endif /* H5_HAVE_PARALLEL */
 
 #endif /* H5FDprivate_H */
diff --git a/src/H5Fmpi.c b/src/H5Fmpi.c
index 652c9cc..4b5283e 100644
--- a/src/H5Fmpi.c
+++ b/src/H5Fmpi.c
@@ -15,7 +15,7 @@
  *
  * Created:             H5Fmpi.c
  *                      Jan 10 2008
- *                      Quincey Koziol <koziol@hdfgroup.org>
+ *                      Quincey Koziol
  *
  * Purpose:             MPI-related routines.
  *
@@ -68,35 +68,6 @@
 /*******************/
 
 #ifdef H5_HAVE_PARALLEL
-
-/*-------------------------------------------------------------------------
- * Function:    H5F_get_mpi_handle
- *
- * Purpose:     Retrieves MPI File handle.
- *
- * Return:      Success:        The size (positive)
- *              Failure:        Negative
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5F_get_mpi_handle(const H5F_t *f, MPI_File **f_handle)
-{
-    herr_t ret_value = SUCCEED;
-    hid_t  fapl_id   = H5I_INVALID_HID;
-
-    FUNC_ENTER_NOAPI(FAIL)
-
-    HDassert(f && f->shared);
-
-    /* Dispatch to driver */
-    if ((ret_value = H5FD_get_vfd_handle(f->shared->lf, fapl_id, (void **)f_handle)) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't get mpi file handle")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_get_mpi_handle() */
-
 /*-------------------------------------------------------------------------
  * Function:    H5F_mpi_get_rank
  *
@@ -336,13 +307,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Fget_mpi_atomicity(hid_t file_id, hbool_t *flag)
+H5Fget_mpi_atomicity(hid_t file_id, hbool_t *flag /*out*/)
 {
     H5VL_object_t *vol_obj   = NULL;
     herr_t         ret_value = SUCCEED;
 
     FUNC_ENTER_API(FAIL);
-    H5TRACE2("e", "i*b", file_id, flag);
+    H5TRACE2("e", "ix", file_id, flag);
 
     /* Get the file object */
     if (NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(file_id, H5I_FILE)))
@@ -420,31 +391,4 @@ H5F_mpi_retrieve_comm(hid_t loc_id, hid_t acspl_id, MPI_Comm *mpi_comm)
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_mpi_retrieve_comm */
-
-/*-------------------------------------------------------------------------
- * Function:    H5F_get_mpi_info
- *
- * Purpose:     Retrieves MPI File info.
- *
- * Return:      Success:        The size (positive)
- *              Failure:        Negative
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5F_get_mpi_info(const H5F_t *f, MPI_Info **f_info)
-{
-    herr_t ret_value = SUCCEED;
-
-    FUNC_ENTER_NOAPI(FAIL)
-
-    HDassert(f && f->shared);
-
-    /* Dispatch to driver */
-    if ((ret_value = H5FD_get_mpi_info(f->shared->lf, (void **)f_info)) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't get mpi file info")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_get_mpi_info() */
 #endif /* H5_HAVE_PARALLEL */
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index d661829..0c4c51d 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -978,13 +978,11 @@ H5_DLL herr_t H5F_eoa_dirty(H5F_t *f);
 
 /* Parallel I/O (i.e. MPI) related routines */
 #ifdef H5_HAVE_PARALLEL
-H5_DLL herr_t   H5F_get_mpi_handle(const H5F_t *f, MPI_File **f_handle);
 H5_DLL int      H5F_mpi_get_rank(const H5F_t *f);
 H5_DLL MPI_Comm H5F_mpi_get_comm(const H5F_t *f);
 H5_DLL int      H5F_shared_mpi_get_size(const H5F_shared_t *f_sh);
 H5_DLL int      H5F_mpi_get_size(const H5F_t *f);
 H5_DLL herr_t   H5F_mpi_retrieve_comm(hid_t loc_id, hid_t acspl_id, MPI_Comm *mpi_comm);
-H5_DLL herr_t   H5F_get_mpi_info(const H5F_t *f, MPI_Info **f_info);
 H5_DLL herr_t   H5F_get_mpi_atomicity(H5F_t *file, hbool_t *flag);
 H5_DLL herr_t   H5F_set_mpi_atomicity(H5F_t *file, hbool_t flag);
 #endif /* H5_HAVE_PARALLEL */
diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index e2db3e4..b521232 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -209,12 +209,12 @@
 /* Definition for 'mdc log location' flag */
 #define H5F_ACS_MDC_LOG_LOCATION_SIZE  sizeof(char *)
 #define H5F_ACS_MDC_LOG_LOCATION_DEF   NULL /* default is no log location */
-#define H5F_ACS_MDC_LOG_LOCATION_ENC   H5P_facc_mdc_log_location_enc
-#define H5F_ACS_MDC_LOG_LOCATION_DEC   H5P_facc_mdc_log_location_dec
-#define H5F_ACS_MDC_LOG_LOCATION_DEL   H5P_facc_mdc_log_location_del
-#define H5F_ACS_MDC_LOG_LOCATION_COPY  H5P_facc_mdc_log_location_copy
-#define H5F_ACS_MDC_LOG_LOCATION_CMP   H5P_facc_mdc_log_location_cmp
-#define H5F_ACS_MDC_LOG_LOCATION_CLOSE H5P_facc_mdc_log_location_close
+#define H5F_ACS_MDC_LOG_LOCATION_ENC   H5P__facc_mdc_log_location_enc
+#define H5F_ACS_MDC_LOG_LOCATION_DEC   H5P__facc_mdc_log_location_dec
+#define H5F_ACS_MDC_LOG_LOCATION_DEL   H5P__facc_mdc_log_location_del
+#define H5F_ACS_MDC_LOG_LOCATION_COPY  H5P__facc_mdc_log_location_copy
+#define H5F_ACS_MDC_LOG_LOCATION_CMP   H5P__facc_mdc_log_location_cmp
+#define H5F_ACS_MDC_LOG_LOCATION_CLOSE H5P__facc_mdc_log_location_close
 /* Definition for 'start metadata cache logging on access' flag */
 #define H5F_ACS_START_MDC_LOG_ON_ACCESS_SIZE sizeof(hbool_t)
 #define H5F_ACS_START_MDC_LOG_ON_ACCESS_DEF  FALSE
@@ -366,12 +366,12 @@ static herr_t H5P__facc_vfd_swmr_config_enc(const void *value, void **_pp, size_
 static herr_t H5P__facc_vfd_swmr_config_dec(const void **_pp, void *value);
 
 /* Metadata cache log location property callbacks */
-static herr_t H5P_facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size);
-static herr_t H5P_facc_mdc_log_location_dec(const void **_pp, void *value);
-static herr_t H5P_facc_mdc_log_location_del(hid_t prop_id, const char *name, size_t size, void *value);
-static herr_t H5P_facc_mdc_log_location_copy(const char *name, size_t size, void *value);
-static int    H5P_facc_mdc_log_location_cmp(const void *value1, const void *value2, size_t size);
-static herr_t H5P_facc_mdc_log_location_close(const char *name, size_t size, void *value);
+static herr_t H5P__facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size);
+static herr_t H5P__facc_mdc_log_location_dec(const void **_pp, void *value);
+static herr_t H5P__facc_mdc_log_location_del(hid_t prop_id, const char *name, size_t size, void *value);
+static herr_t H5P__facc_mdc_log_location_copy(const char *name, size_t size, void *value);
+static int    H5P__facc_mdc_log_location_cmp(const void *value1, const void *value2, size_t size);
+static herr_t H5P__facc_mdc_log_location_close(const char *name, size_t size, void *value);
 
 /* Metadata cache image property callbacks */
 static int    H5P__facc_cache_image_config_cmp(const void *_config1, const void *_config2,
@@ -1573,13 +1573,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_family_offset(hid_t fapl_id, hsize_t *offset)
+H5Pget_family_offset(hid_t fapl_id, hsize_t *offset /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*h", fapl_id, offset);
+    H5TRACE2("e", "ix", fapl_id, offset);
 
     /* Get the plist structure */
     if (H5P_DEFAULT == fapl_id)
@@ -1651,13 +1651,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_multi_type(hid_t fapl_id, H5FD_mem_t *type)
+H5Pget_multi_type(hid_t fapl_id, H5FD_mem_t *type /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*Mt", fapl_id, type);
+    H5TRACE2("e", "ix", fapl_id, type);
 
     /* Get the plist structure */
     if (H5P_DEFAULT == fapl_id)
@@ -1745,13 +1745,14 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_cache(hid_t plist_id, int *mdc_nelmts, size_t *rdcc_nslots, size_t *rdcc_nbytes, double *rdcc_w0)
+H5Pget_cache(hid_t plist_id, int *mdc_nelmts, size_t *rdcc_nslots /*out*/, size_t *rdcc_nbytes /*out*/,
+             double *rdcc_w0 /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE5("e", "i*Is*z*z*d", plist_id, mdc_nelmts, rdcc_nslots, rdcc_nbytes, rdcc_w0);
+    H5TRACE5("e", "i*Isxxx", plist_id, mdc_nelmts, rdcc_nslots, rdcc_nbytes, rdcc_w0);
 
     /* Get the plist structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
@@ -1838,23 +1839,22 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_mdc_image_config(hid_t plist_id, H5AC_cache_image_config_t *config_ptr)
+H5Pget_mdc_image_config(hid_t plist_id, H5AC_cache_image_config_t *config /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*CC", plist_id, config_ptr);
+    H5TRACE2("e", "ix", plist_id, config);
 
     /* Get the plist structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
 
-    /* validate the config_ptr */
-    if (config_ptr == NULL)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL config_ptr on entry.")
-
-    if (config_ptr->version != H5AC__CURR_CACHE_IMAGE_CONFIG_VERSION)
+    /* validate the config ptr */
+    if (config == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL config ptr on entry.")
+    if (config->version != H5AC__CURR_CACHE_IMAGE_CONFIG_VERSION)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Unknown image config version.")
 
     /* If we ever support multiple versions of H5AC_cache_config_t, we
@@ -1863,7 +1863,7 @@ H5Pget_mdc_image_config(hid_t plist_id, H5AC_cache_image_config_t *config_ptr)
      */
 
     /* Get the current initial metadata cache resize configuration */
-    if (H5P_get(plist, H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_NAME, config_ptr) < 0)
+    if (H5P_get(plist, H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_NAME, config) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get metadata cache initial image config")
 
 done:
@@ -1919,7 +1919,7 @@ done:
  * Purpose:    Retrieve the metadata cache initial resize configuration
  *        from the target FAPL.
  *
- *        Observe that the function will fail if config_ptr is
+ *        Observe that the function will fail if config is
  *        NULL, or if config_ptr->version specifies an unknown
  *        version of H5AC_cache_config_t.
  *
@@ -1931,23 +1931,22 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_mdc_config(hid_t plist_id, H5AC_cache_config_t *config_ptr)
+H5Pget_mdc_config(hid_t plist_id, H5AC_cache_config_t *config /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*Cc", plist_id, config_ptr);
+    H5TRACE2("e", "ix", plist_id, config);
 
     /* Get the plist structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
 
-    /* validate the config_ptr */
-    if (config_ptr == NULL)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL config_ptr on entry.")
-
-    if (config_ptr->version != H5AC__CURR_CACHE_CONFIG_VERSION)
+    /* validate the config ptr */
+    if (config == NULL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL config ptr on entry.")
+    if (config->version != H5AC__CURR_CACHE_CONFIG_VERSION)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Unknown config version.")
 
     /* If we ever support multiple versions of H5AC_cache_config_t, we
@@ -1956,7 +1955,7 @@ H5Pget_mdc_config(hid_t plist_id, H5AC_cache_config_t *config_ptr)
      */
 
     /* Get the current initial metadata cache resize configuration */
-    if (H5P_get(plist, H5F_ACS_META_CACHE_INIT_CONFIG_NAME, config_ptr) < 0)
+    if (H5P_get(plist, H5F_ACS_META_CACHE_INIT_CONFIG_NAME, config) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get metadata cache initial resize config")
 
 done:
@@ -1985,13 +1984,6 @@ done:
  * Programmer:    Quincey Koziol
  *        June, 1999
  *
- * Modifications:
- *
- *        Raymond Lu
- *         Tuesday, Oct 23, 2001
- *        Changed the file access list to the new generic property
- *        list.
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2026,13 +2018,6 @@ done:
  * Programmer:    Quincey Koziol
  *              June, 1999
  *
- * Modifications:
- *
- *        Raymond Lu
- *        Tuesday, Oct 23, 2001
- *        Changed the file access list to the new generic property
- *        list.
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2067,8 +2052,6 @@ done:
  * Programmer:  Raymond Lu
  *              November, 2001
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2102,18 +2085,16 @@ done:
  * Programmer:  Raymond Lu
  *              November, 2001
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_fclose_degree(hid_t plist_id, H5F_close_degree_t *degree)
+H5Pget_fclose_degree(hid_t plist_id, H5F_close_degree_t *degree /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*Fd", plist_id, degree);
+    H5TRACE2("e", "ix", plist_id, degree);
 
     /* Get the plist structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
@@ -2146,13 +2127,6 @@ done:
  * Programmer:    Quincey Koziol
  *              Friday, August 25, 2000
  *
- * Modifications:
- *
- *        Raymond Lu
- *        Tuesday, Oct 23, 2001
- *        Changed the file access list to the new generic property
- *        list.
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2187,13 +2161,6 @@ done:
  * Programmer:    Quincey Koziol
  *              Friday, August 29, 2000
  *
- * Modifications:
- *
- *        Raymond Lu
- *         Tuesday, Oct 23, 2001
- *        Changed the file access list to the new generic property
- *        list.
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2239,13 +2206,6 @@ done:
  * Programmer:    Quincey Koziol
  *              Thursday, September 21, 2000
  *
- * Modifications:
- *
- *        Raymond Lu
- *         Tuesday, Oct 23, 2001
- *        Changed the file access list to the new generic property
- *        list.
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2280,13 +2240,6 @@ done:
  * Programmer:    Quincey Koziol
  *              Thursday, September 21, 2000
  *
- * Modifications:
- *
- *        Raymond Lu
- *         Tuesday, Oct 23, 2001
- *        Changed the file access list to the new generic property
- *        list.
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2331,8 +2284,6 @@ done:
  * Programmer:    Quincey Koziol
  *              Wednesday, June 5, 2002
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2367,8 +2318,6 @@ done:
  * Programmer:    Quincey Koziol
  *              Wednesday, June 5, 2002
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -2510,7 +2459,6 @@ H5Pset_libver_bounds(hid_t plist_id, H5F_libver_t low, H5F_libver_t high)
     /* Check args */
     if (low < 0 || low > H5F_LIBVER_LATEST)
         HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "low bound is not valid")
-
     if (high < 0 || high > H5F_LIBVER_LATEST)
         HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "high bound is not valid")
 
@@ -2562,15 +2510,13 @@ H5Pget_libver_bounds(hid_t plist_id, H5F_libver_t *low /*out*/, H5F_libver_t *hi
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
 
     /* Get values */
-    if (low) {
+    if (low)
         if (H5P_get(plist, H5F_ACS_LIBVER_LOW_BOUND_NAME, low) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get low bound for library format versions")
-    }
 
-    if (high) {
+    if (high)
         if (H5P_get(plist, H5F_ACS_LIBVER_HIGH_BOUND_NAME, high) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get high bound for library format versions")
-    }
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -2630,13 +2576,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_elink_file_cache_size(hid_t plist_id, unsigned *efc_size)
+H5Pget_elink_file_cache_size(hid_t plist_id, unsigned *efc_size /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*Iu", plist_id, efc_size);
+    H5TRACE2("e", "ix", plist_id, efc_size);
 
     /* Get the plist structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
@@ -2735,22 +2681,22 @@ done:
 /*-------------------------------------------------------------------------
  * Function: H5Pget_file_image
  *
- * Purpose:     If the file image exists and buf_ptr_ptr is not NULL,
+ * Purpose:     If the file image exists and buf is not NULL,
  *        allocate a buffer of the correct size, copy the image into
  *        the new buffer, and return the buffer to the caller in
- *        *buf_ptr_ptr.  Do this using the file image callbacks
+ *        *buf.  Do this using the file image callbacks
  *        if defined.
  *
  *        NB: It is the responsibility of the caller to free the
- *        buffer whose address is returned in *buf_ptr_ptr.  Do
+ *        buffer whose address is returned in *buf.  Do
  *        this using free if the file image callbacks are not
  *        defined, or with whatever method is appropriate if
  *        the callbacks are defined.
  *
- *              If buf_ptr_ptr is not NULL, and no image exists, set
- *        *buf_ptr_ptr to NULL.
+ *              If buf is not NULL, and no image exists, set
+ *        *buf to NULL.
  *
- *        If buf_len_ptr is not NULL, set *buf_len_ptr equal
+ *        If buf_len is not NULL, set *buf_len equal
  *        to the length of the file image if it exists, and
  *        to 0 if it does not.
  *
@@ -2762,14 +2708,14 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_file_image(hid_t fapl_id, void **buf_ptr_ptr, size_t *buf_len_ptr)
+H5Pget_file_image(hid_t fapl_id, void **buf /*out*/, size_t *buf_len /*out*/)
 {
     H5P_genplist_t *       fapl;                /* Property list pointer */
     H5FD_file_image_info_t image_info;          /* File image info */
     herr_t                 ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE3("e", "i**x*z", fapl_id, buf_ptr_ptr, buf_len_ptr);
+    H5TRACE3("e", "ixx", fapl_id, buf, buf_len);
 
     /* Get the plist structure */
     if (NULL == (fapl = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
@@ -2784,11 +2730,11 @@ H5Pget_file_image(hid_t fapl_id, void **buf_ptr_ptr, size_t *buf_len_ptr)
              ((image_info.buffer == NULL) && (image_info.size == 0)));
 
     /* Set output size */
-    if (buf_len_ptr != NULL)
-        *buf_len_ptr = image_info.size;
+    if (buf_len != NULL)
+        *buf_len = image_info.size;
 
     /* Duplicate the image if desired, using callbacks if available */
-    if (buf_ptr_ptr != NULL) {
+    if (buf != NULL) {
         void *copy_ptr = NULL; /* Copy of memory image */
 
         if (image_info.buffer != NULL) {
@@ -2813,7 +2759,7 @@ H5Pget_file_image(hid_t fapl_id, void **buf_ptr_ptr, size_t *buf_len_ptr)
                 H5MM_memcpy(copy_ptr, image_info.buffer, image_info.size);
         } /* end if */
 
-        *buf_ptr_ptr = copy_ptr;
+        *buf = copy_ptr;
     } /* end if */
 
 done:
@@ -2898,7 +2844,7 @@ done:
 } /* end H5Pset_file_image_callbacks() */
 
 /*-------------------------------------------------------------------------
- * Function: H5Pget_file_image_callbacks
+ * Function:    H5Pget_file_image_callbacks
  *
  * Purpose:     Sets the callbacks for file images. Some file drivers allow
  *              the use of user-defined callbacks for allocating, freeing and
@@ -2913,14 +2859,14 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_file_image_callbacks(hid_t fapl_id, H5FD_file_image_callbacks_t *callbacks_ptr)
+H5Pget_file_image_callbacks(hid_t fapl_id, H5FD_file_image_callbacks_t *callbacks /*out*/)
 {
     H5P_genplist_t *       fapl;                /* Property list pointer */
     H5FD_file_image_info_t info;                /* File image info */
     herr_t                 ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*DI", fapl_id, callbacks_ptr);
+    H5TRACE2("e", "ix", fapl_id, callbacks);
 
     /* Get the plist structure */
     if (NULL == (fapl = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
@@ -2933,17 +2879,17 @@ H5Pget_file_image_callbacks(hid_t fapl_id, H5FD_file_image_callbacks_t *callback
     /* verify file image field consistency */
     HDassert(((info.buffer != NULL) && (info.size > 0)) || ((info.buffer == NULL) && (info.size == 0)));
 
-    /* verify that callbacks_ptr is not NULL */
-    if (NULL == callbacks_ptr)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL callbacks_ptr")
+    /* verify that callbacks is not NULL */
+    if (NULL == callbacks)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL callbacks ptr")
 
     /* Transfer values to parameters */
-    *callbacks_ptr = info.callbacks;
+    *callbacks = info.callbacks;
 
     /* Copy udata if it exists */
     if (info.callbacks.udata != NULL) {
         HDassert(info.callbacks.udata_copy);
-        if ((callbacks_ptr->udata = info.callbacks.udata_copy(info.callbacks.udata)) == 0)
+        if ((callbacks->udata = info.callbacks.udata_copy(info.callbacks.udata)) == 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't copy udata")
     } /* end if */
 
@@ -4358,14 +4304,14 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_object_flush_cb(hid_t plist_id, H5F_flush_cb_t *func, void **udata)
+H5Pget_object_flush_cb(hid_t plist_id, H5F_flush_cb_t *func /*out*/, void **udata /*out*/)
 {
     H5P_genplist_t *   plist; /* Property list pointer */
     H5F_object_flush_t flush_info;
     herr_t             ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE3("e", "i*FF**x", plist_id, func, udata);
+    H5TRACE3("e", "ixx", plist_id, func, udata);
 
     /* Get the plist structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
@@ -4445,15 +4391,15 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_mdc_log_options(hid_t plist_id, hbool_t *is_enabled, char *location, size_t *location_size,
-                       hbool_t *start_on_access)
+H5Pget_mdc_log_options(hid_t plist_id, hbool_t *is_enabled /*out*/, char *location /*out*/,
+                       size_t *location_size /*out*/, hbool_t *start_on_access /*out*/)
 {
-    H5P_genplist_t *plist;               /* Property list pointer */
-    char *          location_ptr;        /* Pointer to location string */
-    herr_t          ret_value = SUCCEED; /* Return value */
+    H5P_genplist_t *plist;                  /* Property list pointer */
+    char *          location_ptr = NULL;    /* Pointer to location string */
+    herr_t          ret_value    = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE5("e", "i*b*s*z*b", plist_id, is_enabled, location, location_size, start_on_access);
+    H5TRACE5("e", "ixxxx", plist_id, is_enabled, location, location_size, start_on_access);
 
     /* Get the property list structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
@@ -4482,14 +4428,14 @@ H5Pget_mdc_log_options(hid_t plist_id, hbool_t *is_enabled, char *location, size
             *location_size = HDstrlen(location_ptr) + 1;
         else
             *location_size = 0;
-    }
+    } /* end if */
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Pget_mdc_log_options() */
 
 /*-------------------------------------------------------------------------
- * Function:       H5P_facc_mdc_log_location_enc
+ * Function:       H5P__facc_mdc_log_location_enc
  *
  * Purpose:        Callback routine which is called whenever the metadata
  *                 cache log location property in the file access property
@@ -4501,7 +4447,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5P_facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size)
+H5P__facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size)
 {
     const char *log_location = *(const char *const *)value;
     uint8_t **  pp           = (uint8_t **)_pp;
@@ -4509,7 +4455,7 @@ H5P_facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size)
     uint64_t    enc_value;
     unsigned    enc_size;
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     HDcompile_assert(sizeof(size_t) <= sizeof(uint64_t));
 
@@ -4538,10 +4484,10 @@ H5P_facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size)
         *size += len;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5P_facc_mdc_log_location_enc() */
+} /* end H5P__facc_mdc_log_location_enc() */
 
 /*-------------------------------------------------------------------------
- * Function:       H5P_facc_mdc_log_location_dec
+ * Function:       H5P__facc_mdc_log_location_dec
  *
  * Purpose:        Callback routine which is called whenever the metadata
  *                 cache log location property in the file access property
@@ -4553,7 +4499,7 @@ H5P_facc_mdc_log_location_enc(const void *value, void **_pp, size_t *size)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5P_facc_mdc_log_location_dec(const void **_pp, void *_value)
+H5P__facc_mdc_log_location_dec(const void **_pp, void *_value)
 {
     char **         log_location = (char **)_value;
     const uint8_t **pp           = (const uint8_t **)_pp;
@@ -4562,7 +4508,7 @@ H5P_facc_mdc_log_location_dec(const void **_pp, void *_value)
     unsigned        enc_size;  /* Size of encoded property */
     herr_t          ret_value = SUCCEED;
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     HDassert(pp);
     HDassert(*pp);
@@ -4591,10 +4537,10 @@ H5P_facc_mdc_log_location_dec(const void **_pp, void *_value)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5P_facc_mdc_log_location_dec() */
+} /* end H5P__facc_mdc_log_location_dec() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5P_facc_mdc_log_location_del
+ * Function:    H5P__facc_mdc_log_location_del
  *
  * Purpose:     Frees memory used to store the metadata cache log location.
  *
@@ -4603,20 +4549,20 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5P_facc_mdc_log_location_del(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name,
-                              size_t H5_ATTR_UNUSED size, void *value)
+H5P__facc_mdc_log_location_del(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_UNUSED *name,
+                               size_t H5_ATTR_UNUSED size, void *value)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     HDassert(value);
 
     H5MM_xfree(*(void **)value);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5P_facc_mdc_log_location_del() */
+} /* end H5P__facc_mdc_log_location_del() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5P_facc_mdc_log_location_copy
+ * Function:    H5P__facc_mdc_log_location_copy
  *
  * Purpose:     Creates a copy of the metadata cache log location string.
  *
@@ -4625,19 +4571,19 @@ H5P_facc_mdc_log_location_del(hid_t H5_ATTR_UNUSED prop_id, const char H5_ATTR_U
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5P_facc_mdc_log_location_copy(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
+H5P__facc_mdc_log_location_copy(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     HDassert(value);
 
     *(char **)value = H5MM_xstrdup(*(const char **)value);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5P_facc_mdc_log_location_copy() */
+} /* end H5P__facc_mdc_log_location_copy() */
 
 /*-------------------------------------------------------------------------
- * Function:       H5P_facc_mdc_log_location_cmp
+ * Function:       H5P__facc_mdc_log_location_cmp
  *
  * Purpose:        Callback routine which is called whenever the metadata
  *                 cache log location property in the file creation property
@@ -4647,14 +4593,14 @@ H5P_facc_mdc_log_location_copy(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_U
  *
  *-------------------------------------------------------------------------
  */
-static int
-H5P_facc_mdc_log_location_cmp(const void *value1, const void *value2, size_t H5_ATTR_UNUSED size)
+static H5_ATTR_PURE int
+H5P__facc_mdc_log_location_cmp(const void *value1, const void *value2, size_t H5_ATTR_UNUSED size)
 {
     const char *pref1     = *(const char *const *)value1;
     const char *pref2     = *(const char *const *)value2;
     int         ret_value = 0;
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     if (NULL == pref1 && NULL != pref2)
         HGOTO_DONE(1);
@@ -4665,10 +4611,10 @@ H5P_facc_mdc_log_location_cmp(const void *value1, const void *value2, size_t H5_
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5P_facc_mdc_log_location_cmp() */
+} /* end H5P__facc_mdc_log_location_cmp() */
 
 /*-------------------------------------------------------------------------
- * Function:    H5P_facc_mdc_log_location_close
+ * Function:    H5P__facc_mdc_log_location_close
  *
  * Purpose:     Frees memory used to store the metadata cache log location
  *              string
@@ -4678,16 +4624,16 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5P_facc_mdc_log_location_close(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
+H5P__facc_mdc_log_location_close(const char H5_ATTR_UNUSED *name, size_t H5_ATTR_UNUSED size, void *value)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     HDassert(value);
 
     H5MM_xfree(*(void **)value);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5P_facc_mdc_log_location_close() */
+} /* end H5P__facc_mdc_log_location_close() */
 
 /*-------------------------------------------------------------------------
  * Function:    H5Pset_evict_on_close
@@ -4756,13 +4702,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_evict_on_close(hid_t fapl_id, hbool_t *evict_on_close)
+H5Pget_evict_on_close(hid_t fapl_id, hbool_t *evict_on_close /*out*/)
 {
     H5P_genplist_t *plist;               /* property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*b", fapl_id, evict_on_close);
+    H5TRACE2("e", "ix", fapl_id, evict_on_close);
 
     /* Compare the property list's class against the other class */
     if (TRUE != H5P_isa_class(fapl_id, H5P_FILE_ACCESS))
@@ -5017,12 +4963,12 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_all_coll_metadata_ops(hid_t plist_id, hbool_t *is_collective)
+H5Pget_all_coll_metadata_ops(hid_t plist_id, hbool_t *is_collective /*out*/)
 {
     herr_t ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*b", plist_id, is_collective);
+    H5TRACE2("e", "ix", plist_id, is_collective);
 
     /* Compare the property list's class against the other class */
     /* (Dataset, group, attribute, and named datype  access property lists
@@ -5106,13 +5052,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_mpi_params(hid_t plist_id, MPI_Comm *comm, MPI_Info *info)
+H5Pget_mpi_params(hid_t plist_id, MPI_Comm *comm /*out*/, MPI_Info *info /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE3("e", "i*Mc*Mi", plist_id, comm, info);
+    H5TRACE3("e", "ixx", plist_id, comm, info);
 
     /* Make sure that the property list is a fapl */
     if (TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
@@ -5556,13 +5502,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_coll_metadata_write(hid_t plist_id, hbool_t *is_collective)
+H5Pget_coll_metadata_write(hid_t plist_id, hbool_t *is_collective /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*b", plist_id, is_collective);
+    H5TRACE2("e", "ix", plist_id, is_collective);
 
     /* Compare the property list's class against the other class */
     if (TRUE != H5P_isa_class(plist_id, H5P_FILE_ACCESS))
@@ -5643,13 +5589,14 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_page_buffer_size(hid_t plist_id, size_t *buf_size, unsigned *min_meta_perc, unsigned *min_raw_perc)
+H5Pget_page_buffer_size(hid_t plist_id, size_t *buf_size /*out*/, unsigned *min_meta_perc /*out*/,
+                        unsigned *min_raw_perc /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE4("e", "i*z*Iu*Iu", plist_id, buf_size, min_meta_perc, min_raw_perc);
+    H5TRACE4("e", "ixxx", plist_id, buf_size, min_meta_perc, min_raw_perc);
 
     /* Get the plist structure */
     if (NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
@@ -5861,13 +5808,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_vol_id(hid_t plist_id, hid_t *vol_id)
+H5Pget_vol_id(hid_t plist_id, hid_t *vol_id /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i*i", plist_id, vol_id);
+    H5TRACE2("e", "ix", plist_id, vol_id);
 
     /* Get property list for ID */
     if (NULL == (plist = (H5P_genplist_t *)H5I_object_verify(plist_id, H5I_GENPROP_LST)))
@@ -5943,13 +5890,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_vol_info(hid_t plist_id, void **vol_info)
+H5Pget_vol_info(hid_t plist_id, void **vol_info /*out*/)
 {
     H5P_genplist_t *plist;               /* Property list pointer */
     herr_t          ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "i**x", plist_id, vol_info);
+    H5TRACE2("e", "ix", plist_id, vol_info);
 
     /* Get property list for ID */
     if (NULL == (plist = (H5P_genplist_t *)H5I_object_verify(plist_id, H5I_GENPROP_LST)))
diff --git a/src/H5mpi.c b/src/H5mpi.c
index a83fdac..9749721 100644
--- a/src/H5mpi.c
+++ b/src/H5mpi.c
@@ -25,7 +25,7 @@
 /****************/
 /* Local Macros */
 /****************/
-#define TWO_GIG_LIMIT (1 << 31)
+#define TWO_GIG_LIMIT INT32_MAX
 #ifndef H5_MAX_MPI_COUNT
 #define H5_MAX_MPI_COUNT (1 << 30)
 #endif
@@ -33,7 +33,7 @@
 /*******************/
 /* Local Variables */
 /*******************/
-static hsize_t bigio_count = H5_MAX_MPI_COUNT;
+static hsize_t bigio_count_g = H5_MAX_MPI_COUNT;
 
 /*-------------------------------------------------------------------------
  * Function:  H5_mpi_set_bigio_count
@@ -42,7 +42,7 @@ static hsize_t bigio_count = H5_MAX_MPI_COUNT;
  *            when we utilize derived datatypes.  This is of
  *            particular interest for allowing nightly testing
  *
- * Return:    The current/previous value of bigio_count.
+ * Return:    The current/previous value of bigio_count_g.
  *
  * Programmer: Richard Warren,  March 10, 2017
  *
@@ -51,10 +51,10 @@ static hsize_t bigio_count = H5_MAX_MPI_COUNT;
 hsize_t
 H5_mpi_set_bigio_count(hsize_t new_count)
 {
-    hsize_t orig_count = bigio_count;
+    hsize_t orig_count = bigio_count_g;
 
     if ((new_count > 0) && (new_count < (hsize_t)TWO_GIG_LIMIT)) {
-        bigio_count = new_count;
+        bigio_count_g = new_count;
     }
     return orig_count;
 } /* end H5_mpi_set_bigio_count() */
@@ -63,9 +63,9 @@ H5_mpi_set_bigio_count(hsize_t new_count)
  * Function:  H5_mpi_get_bigio_count
  *
  * Purpose:   Allow other HDF5 library functions to access
- *            the current value for bigio_count.
+ *            the current value for bigio_count_g.
  *
- * Return:    The current/previous value of bigio_count.
+ * Return:    The current/previous value of bigio_count_g.
  *
  * Programmer: Richard Warren,  October 7, 2019
  *
@@ -74,7 +74,7 @@ H5_mpi_set_bigio_count(hsize_t new_count)
 hsize_t
 H5_mpi_get_bigio_count(void)
 {
-    return bigio_count;
+    return bigio_count_g;
 }
 
 /*-------------------------------------------------------------------------
@@ -210,7 +210,7 @@ H5_mpi_comm_free(MPI_Comm *comm)
         HGOTO_ERROR(H5E_INTERNAL, H5E_BADVALUE, FAIL, "comm pointer cannot be NULL")
 
     /* Free the communicator */
-    if (MPI_COMM_NULL != *comm)
+    if (MPI_COMM_WORLD != *comm && MPI_COMM_NULL != *comm)
         MPI_Comm_free(comm);
 
     *comm = MPI_COMM_NULL;
@@ -471,8 +471,8 @@ H5_mpio_create_large_type(hsize_t num_elements, MPI_Aint stride_bytes, MPI_Datat
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Calculate how many Big MPI datatypes are needed to represent the buffer */
-    num_big_types = (int)(num_elements / bigio_count);
-    leftover      = (hsize_t)num_elements - (hsize_t)num_big_types * bigio_count;
+    num_big_types = (int)(num_elements / bigio_count_g);
+    leftover      = (hsize_t)num_elements - (hsize_t)num_big_types * bigio_count_g;
     H5_CHECKED_ASSIGN(remaining_bytes, int, leftover, hsize_t);
 
     /* Create a contiguous datatype of size equal to the largest
@@ -481,11 +481,11 @@ H5_mpio_create_large_type(hsize_t num_elements, MPI_Aint stride_bytes, MPI_Datat
      * use type_hvector to create the type with the displacement provided
      */
     if (0 == stride_bytes) {
-        if (MPI_SUCCESS != (mpi_code = MPI_Type_contiguous((int)bigio_count, old_type, &inner_type)))
+        if (MPI_SUCCESS != (mpi_code = MPI_Type_contiguous((int)bigio_count_g, old_type, &inner_type)))
             HMPI_GOTO_ERROR(FAIL, "MPI_Type_contiguous failed", mpi_code)
     } /* end if */
     else if (MPI_SUCCESS !=
-             (mpi_code = MPI_Type_create_hvector((int)bigio_count, 1, stride_bytes, old_type, &inner_type)))
+             (mpi_code = MPI_Type_create_hvector((int)bigio_count_g, 1, stride_bytes, old_type, &inner_type)))
         HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hvector failed", mpi_code)
 
     /* Create a contiguous datatype of the buffer (minus the remaining < 2GB part)
@@ -510,7 +510,7 @@ H5_mpio_create_large_type(hsize_t num_elements, MPI_Aint stride_bytes, MPI_Datat
                 HMPI_GOTO_ERROR(FAIL, "MPI_Type_contiguous failed", mpi_code)
         } /* end if */
         else if (MPI_SUCCESS != (mpi_code = MPI_Type_create_hvector(
-                                     (int)(num_elements - (hsize_t)num_big_types * bigio_count), 1,
+                                     (int)(num_elements - (hsize_t)num_big_types * bigio_count_g), 1,
                                      stride_bytes, old_type, &leftover_type)))
             HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_hvector failed", mpi_code)
 
@@ -529,7 +529,7 @@ H5_mpio_create_large_type(hsize_t num_elements, MPI_Aint stride_bytes, MPI_Datat
         block_len[0] = 1;
         block_len[1] = 1;
         disp[0]      = 0;
-        disp[1]      = (old_extent + stride_bytes) * num_big_types * (MPI_Aint)bigio_count;
+        disp[1]      = (old_extent + stride_bytes) * num_big_types * (MPI_Aint)bigio_count_g;
 
         if (MPI_SUCCESS != (mpi_code = MPI_Type_create_struct(2, block_len, disp, type, new_type)))
             HMPI_GOTO_ERROR(FAIL, "MPI_Type_create_struct failed", mpi_code)
diff --git a/src/H5public.h b/src/H5public.h
index 2fb4407..8aadddc 100644
--- a/src/H5public.h
+++ b/src/H5public.h
@@ -372,7 +372,6 @@ htri_to_string(htri_t v)
  * \internal (Hoisted here, since it's used by both the
  *            H5Lpublic.h and H5Opublic.h headers) */
 /* Type for object tokens */
-/* (Hoisted here, since it's used by both the H5Lpublic.h and H5Opublic.h headers) */
 typedef struct H5O_token_t {
     uint8_t __data[H5O_MAX_TOKEN_SIZE];
 } H5O_token_t;