sprintf to snprintf (#1815)

* Straightforward conversion of sprintf to the safer snprintf

* Trickier conversion of sprintf to safer snprintf

This involved minor changes to private function signatures to take the size of the buffer.

* Committing clang-format changes

Co-authored-by: github-actions <41898282+github-actions[bot]@users.noreply.github.com>

43 files changed, 376 insertions, 331 deletions

diff --git a/hl/test/test_ds.c b/hl/test/test_ds.c
index 12b6840..cc716aa 100644
--- a/hl/test/test_ds.c
+++ b/hl/test/test_ds.c
@@ -1220,14 +1220,14 @@ test_detachscales(void)
 
     /* make datasets; they are three dimensional*/
     for (i = 0; i < 2; i++) {
-        HDsprintf(dname, "D%d", i);
+        HDsnprintf(dname, sizeof(dname), "D%d", i);
         if (H5LTmake_dataset_int(fid, dname, rank3, dims, buf) < 0)
             goto out;
     }
     /* create datasets and make them dim. scales */
 
     for (i = 0; i < 4; i++) {
-        HDsprintf(dname, "DS%d", i);
+        HDsnprintf(dname, sizeof(dname), "DS%d", i);
         if (H5LTmake_dataset_int(fid, dname, rank1, dims, buf) < 0)
             goto out;
     }
@@ -1235,7 +1235,7 @@ test_detachscales(void)
        two scales attached  */
     if ((did = H5Dopen2(fid, "D0", H5P_DEFAULT)) >= 0) {
         for (i = 0; i < 4; i++) {
-            HDsprintf(dname, "DS%d", i);
+            HDsnprintf(dname, sizeof(dname), "DS%d", i);
             if ((dsid = H5Dopen2(fid, dname, H5P_DEFAULT)) < 0)
                 goto out;
             if (H5DSattach_scale(did, dsid, (unsigned int)i % 3) < 0)
@@ -1252,7 +1252,7 @@ test_detachscales(void)
     /* attach scales to the second dataset */
     if ((did = H5Dopen2(fid, "D1", H5P_DEFAULT)) >= 0) {
         for (i = 0; i < 3; i++) {
-            HDsprintf(dname, "DS%d", i);
+            HDsnprintf(dname, sizeof(dname), "DS%d", i);
             if ((dsid = H5Dopen2(fid, dname, H5P_DEFAULT)) < 0)
                 goto out;
             if (H5DSattach_scale(did, dsid, (unsigned int)i) < 0)
@@ -1273,7 +1273,7 @@ test_detachscales(void)
         goto out;
 
     for (i = 0; i < 2; i++) {
-        HDsprintf(dname, "D%d", i);
+        HDsnprintf(dname, sizeof(dname), "D%d", i);
         if ((did = H5Dopen2(fid, dname, H5P_DEFAULT)) < 0)
             goto out;
         if (H5DSdetach_scale(did, dsid, (unsigned int)0) < 0)
@@ -1303,7 +1303,7 @@ test_detachscales(void)
        sure that attribute "DIMENSION_LIST" doesn't exist anymore */
     if ((did = H5Dopen2(fid, "D0", H5P_DEFAULT)) >= 0) {
         for (i = 1; i < 4; i++) {
-            HDsprintf(dname, "DS%d", i);
+            HDsnprintf(dname, sizeof(dname), "DS%d", i);
             if ((dsid = H5Dopen2(fid, dname, H5P_DEFAULT)) < 0)
                 goto out;
             if (H5DSdetach_scale(did, dsid, (unsigned int)i % 3) < 0)
@@ -2984,10 +2984,10 @@ test_simple(void)
     if ((sid = H5Screate_simple(rank, dims, NULL)) < 0)
         goto out;
     for (i = 0; i < 5; i++) {
-        HDsprintf(dname, "dset_%d", i);
+        HDsnprintf(dname, sizeof(dname), "dset_%d", i);
         if ((did = H5Dcreate2(gid, dname, H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             goto out;
-        HDsprintf(sname, "ds_%d", i);
+        HDsnprintf(sname, sizeof(sname), "ds_%d", i);
         if ((dsid = H5Dcreate2(gid, sname, H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             goto out;
         if (H5DSset_scale(dsid, "scale") < 0)
@@ -3004,11 +3004,11 @@ test_simple(void)
      */
 
     for (i = 0; i < 5; i++) {
-        HDsprintf(dname, "dset_%d", i);
+        HDsnprintf(dname, sizeof(dname), "dset_%d", i);
         if ((did = H5Dopen2(gid, dname, H5P_DEFAULT)) < 0)
             goto out;
         for (j = 0; j < 5; j++) {
-            HDsprintf(sname, "ds_%d", j);
+            HDsnprintf(sname, sizeof(sname), "ds_%d", j);
             if ((dsid = H5Dopen2(gid, sname, H5P_DEFAULT)) < 0)
                 goto out;
             if (H5DSattach_scale(did, dsid, DIM0) < 0)
@@ -3026,11 +3026,11 @@ test_simple(void)
      */
 
     for (i = 0; i < 5; i++) {
-        HDsprintf(dname, "dset_%d", i);
+        HDsnprintf(dname, sizeof(dname), "dset_%d", i);
         if ((did = H5Dopen2(gid, dname, H5P_DEFAULT)) < 0)
             goto out;
         for (j = 0; j < 5; j++) {
-            HDsprintf(sname, "ds_%d", j);
+            HDsnprintf(sname, sizeof(sname), "ds_%d", j);
             if ((dsid = H5Dopen2(gid, sname, H5P_DEFAULT)) < 0)
                 goto out;
             if (H5DSdetach_scale(did, dsid, DIM0) < 0)
@@ -3048,11 +3048,11 @@ test_simple(void)
      */
 
     for (i = 0; i < 5; i++) {
-        HDsprintf(dname, "dset_%d", i);
+        HDsnprintf(dname, sizeof(dname), "dset_%d", i);
         if ((did = H5Dopen2(gid, dname, H5P_DEFAULT)) < 0)
             goto out;
         for (j = 0; j < 5; j++) {
-            HDsprintf(sname, "ds_%d", j);
+            HDsnprintf(sname, sizeof(sname), "ds_%d", j);
             if ((dsid = H5Dopen2(gid, sname, H5P_DEFAULT)) < 0)
                 goto out;
             if (H5DSattach_scale(did, dsid, DIM0) < 0)
@@ -4292,7 +4292,7 @@ test_iterators(void)
 
     for (i = 0; i < 100; i++) {
         /* make a DS */
-        HDsprintf(dname, "ds_%d", i);
+        HDsnprintf(dname, sizeof(dname), "ds_%d", i);
         if (H5LTmake_dataset_int(fid, dname, rankds, s1_dim, NULL) < 0)
             goto out;
         /* open */
@@ -4442,7 +4442,7 @@ test_rank(void)
         goto out;
 
     for (i = 0; i < 3; i++) {
-        HDsprintf(name, "ds_a_%d", i);
+        HDsnprintf(name, sizeof(name), "ds_a_%d", i);
         if ((dsid = H5Dopen2(fid, name, H5P_DEFAULT)) < 0)
             goto out;
         if (H5DSattach_scale(did, dsid, (unsigned)i) < 0)
@@ -4469,7 +4469,7 @@ test_rank(void)
         goto out;
 
     for (i = 0; i < 3; i++) {
-        HDsprintf(name, "ds_a_%d", i);
+        HDsnprintf(name, sizeof(name), "ds_a_%d", i);
         if ((dsid = H5Dopen2(fid, name, H5P_DEFAULT)) < 0)
             goto out;
         if (H5DSdetach_scale(did, dsid, (unsigned)i) < 0)
@@ -4495,7 +4495,7 @@ test_rank(void)
         goto out;
 
     for (i = 0; i < 3; i++) {
-        HDsprintf(name, "ds_a_%d", i);
+        HDsnprintf(name, sizeof(name), "ds_a_%d", i);
         if ((dsid = H5Dopen2(fid, name, H5P_DEFAULT)) < 0)
             goto out;
         if (H5DSset_scale(dsid, name) < 0)
diff --git a/src/H5Cmpio.c b/src/H5Cmpio.c
index a0cc6bb..a746e54 100644
--- a/src/H5Cmpio.c
+++ b/src/H5Cmpio.c
@@ -199,7 +199,7 @@ H5C_apply_candidate_list(H5F_t *f, H5C_t *cache_ptr, unsigned num_candidates, ha
 
     HDmemset(tbl_buf, 0, sizeof(tbl_buf));
 
-    HDsprintf(&(tbl_buf[0]), "candidate list = ");
+    HDsnprintf(tbl_buf, sizeof(tbl_buf), "candidate list = ");
     for (u = 0; u < num_candidates; u++)
         HDsprintf(&(tbl_buf[HDstrlen(tbl_buf)]), " 0x%llx", (long long)(*(candidates_list_ptr + u)));
     HDsprintf(&(tbl_buf[HDstrlen(tbl_buf)]), "\n");
@@ -266,7 +266,7 @@ H5C_apply_candidate_list(H5F_t *f, H5C_t *cache_ptr, unsigned num_candidates, ha
 #if H5C_APPLY_CANDIDATE_LIST__DEBUG
     for (u = 0; u < 1024; u++)
         tbl_buf[u] = '\0';
-    HDsprintf(&(tbl_buf[0]), "candidate assignment table = ");
+    HDsnprintf(tbl_buf, sizeof(tbl_buf), "candidate assignment table = ");
     for (u = 0; u <= (unsigned)mpi_size; u++)
         HDsprintf(&(tbl_buf[HDstrlen(tbl_buf)]), " %u", candidate_assignment_table[u]);
     HDsprintf(&(tbl_buf[HDstrlen(tbl_buf)]), "\n");
diff --git a/src/H5Tdbg.c b/src/H5Tdbg.c
index 613aa60..515b710 100644
--- a/src/H5Tdbg.c
+++ b/src/H5Tdbg.c
@@ -116,7 +116,7 @@ H5T__print_stats(H5T_path_t H5_ATTR_UNUSED *path, int H5_ATTR_UNUSED *nprint /*i
         else
             nbytes = 0;
         nbytes *= path->stats.nelmts;
-        H5_bandwidth(bandwidth, (double)nbytes, path->stats.times.elapsed);
+        H5_bandwidth(bandwidth, sizeof(bandwidth), (double)nbytes, path->stats.times.elapsed);
         HDfprintf(H5DEBUG(T), "   %-16s %10" PRIdHSIZE " %10u %8s %8s %8s %10s\n", path->name,
                   path->stats.nelmts, path->stats.ncalls, timestrs.user, timestrs.system, timestrs.elapsed,
                   bandwidth);
diff --git a/src/H5Z.c b/src/H5Z.c
index d7ccbb4..23eb731 100644
--- a/src/H5Z.c
+++ b/src/H5Z.c
@@ -166,7 +166,7 @@ H5Z_term_package(void)
                  * units of `B/s', `kB/s', `MB/s', `GB/s', or `TB/s' or
                  * the word `Inf' if the elapsed time is zero.
                  */
-                H5_bandwidth(bandwidth, (double)(H5Z_stat_table_g[i].stats[dir].total),
+                H5_bandwidth(bandwidth, sizeof(bandwidth), (double)(H5Z_stat_table_g[i].stats[dir].total),
                              H5Z_stat_table_g[i].stats[dir].times.elapsed);
 
                 /* Print the statistics */
diff --git a/src/H5private.h b/src/H5private.h
index 974f26c..c8653b7 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -550,7 +550,7 @@ typedef struct {
 } H5_timer_t;
 
 /* Returns library bandwidth as a pretty string */
-H5_DLL void H5_bandwidth(char *buf /*out*/, double nbytes, double nseconds);
+H5_DLL void H5_bandwidth(char *buf /*out*/, size_t bufsize, double nbytes, double nseconds);
 
 /* Timer functionality */
 H5_DLL time_t   H5_now(void);
diff --git a/src/H5timer.c b/src/H5timer.c
index b5dba97..83fd243 100644
--- a/src/H5timer.c
+++ b/src/H5timer.c
@@ -96,7 +96,7 @@
  *-------------------------------------------------------------------------
  */
 void
-H5_bandwidth(char *buf /*out*/, double nbytes, double nseconds)
+H5_bandwidth(char *buf /*out*/, size_t bufsize, double nbytes, double nseconds)
 {
     double bw;
 
@@ -107,35 +107,35 @@ H5_bandwidth(char *buf /*out*/, double nbytes, double nseconds)
         if (H5_DBL_ABS_EQUAL(bw, 0.0))
             HDstrcpy(buf, "0.000  B/s");
         else if (bw < 1.0)
-            HDsprintf(buf, "%10.4e", bw);
+            HDsnprintf(buf, bufsize, "%10.4e", bw);
         else if (bw < (double)H5_KB) {
-            HDsprintf(buf, "%05.4f", bw);
+            HDsnprintf(buf, bufsize, "%05.4f", bw);
             HDstrcpy(buf + 5, "  B/s");
         }
         else if (bw < (double)H5_MB) {
-            HDsprintf(buf, "%05.4f", bw / (double)H5_KB);
+            HDsnprintf(buf, bufsize, "%05.4f", bw / (double)H5_KB);
             HDstrcpy(buf + 5, " kB/s");
         }
         else if (bw < (double)H5_GB) {
-            HDsprintf(buf, "%05.4f", bw / (double)H5_MB);
+            HDsnprintf(buf, bufsize, "%05.4f", bw / (double)H5_MB);
             HDstrcpy(buf + 5, " MB/s");
         }
         else if (bw < (double)H5_TB) {
-            HDsprintf(buf, "%05.4f", bw / (double)H5_GB);
+            HDsnprintf(buf, bufsize, "%05.4f", bw / (double)H5_GB);
             HDstrcpy(buf + 5, " GB/s");
         }
         else if (bw < (double)H5_PB) {
-            HDsprintf(buf, "%05.4f", bw / (double)H5_TB);
+            HDsnprintf(buf, bufsize, "%05.4f", bw / (double)H5_TB);
             HDstrcpy(buf + 5, " TB/s");
         }
         else if (bw < (double)H5_EB) {
-            HDsprintf(buf, "%05.4f", bw / (double)H5_PB);
+            HDsnprintf(buf, bufsize, "%05.4f", bw / (double)H5_PB);
             HDstrcpy(buf + 5, " PB/s");
         }
         else {
-            HDsprintf(buf, "%10.4e", bw);
+            HDsnprintf(buf, bufsize, "%10.4e", bw);
             if (HDstrlen(buf) > 10)
-                HDsprintf(buf, "%10.3e", bw);
+                HDsnprintf(buf, bufsize, "%10.3e", bw);
         } /* end else-if */
     }     /* end else */
 } /* end H5_bandwidth() */
@@ -627,30 +627,31 @@ H5_timer_get_time_string(double seconds)
      * (name? round_up_size? ?)
      */
     if (seconds < 0.0)
-        HDsprintf(s, "N/A");
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "N/A");
     else if (H5_DBL_ABS_EQUAL(0.0, seconds))
-        HDsprintf(s, "0.0 s");
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "0.0 s");
     else if (seconds < 1.0E-6)
         /* t < 1 us, Print time in ns */
-        HDsprintf(s, "%.f ns", seconds * 1.0E9);
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "%.f ns", seconds * 1.0E9);
     else if (seconds < 1.0E-3)
         /* t < 1 ms, Print time in us */
-        HDsprintf(s, "%.1f us", seconds * 1.0E6);
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "%.1f us", seconds * 1.0E6);
     else if (seconds < 1.0)
         /* t < 1 s, Print time in ms */
-        HDsprintf(s, "%.1f ms", seconds * 1.0E3);
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "%.1f ms", seconds * 1.0E3);
     else if (seconds < H5_SEC_PER_MIN)
         /* t < 1 m, Print time in s */
-        HDsprintf(s, "%.2f s", seconds);
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "%.2f s", seconds);
     else if (seconds < H5_SEC_PER_HOUR)
         /* t < 1 h, Print time in m and s */
-        HDsprintf(s, "%.f m %.f s", minutes, remainder_sec);
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "%.f m %.f s", minutes, remainder_sec);
     else if (seconds < H5_SEC_PER_DAY)
         /* t < 1 d, Print time in h, m and s */
-        HDsprintf(s, "%.f h %.f m %.f s", hours, minutes, remainder_sec);
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "%.f h %.f m %.f s", hours, minutes, remainder_sec);
     else
         /* Print time in d, h, m and s */
-        HDsprintf(s, "%.f d %.f h %.f m %.f s", days, hours, minutes, remainder_sec);
+        HDsnprintf(s, H5TIMER_TIME_STRING_LEN, "%.f d %.f h %.f m %.f s", days, hours, minutes,
+                   remainder_sec);
 
     return s;
 } /* end H5_timer_get_time_string() */
diff --git a/test/cache_tagging.c b/test/cache_tagging.c
index 4d07116..f1571f0 100644
--- a/test/cache_tagging.c
+++ b/test/cache_tagging.c
@@ -839,7 +839,7 @@ check_multi_group_creation_tags(void)
 
     for (i = 0; i < MULTIGROUPS; i++) {
 
-        HDsprintf(gname, "%d", i);
+        HDsnprintf(gname, sizeof(gname), "%d", i);
         if ((gid = H5Gcreate2(fid, gname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
         if (H5Gclose(gid) < 0)
@@ -861,7 +861,7 @@ check_multi_group_creation_tags(void)
     for (i = 0; i < MULTIGROUPS; i++) {
 
         /* Re-open the group */
-        HDsprintf(gname, "%d", i);
+        HDsnprintf(gname, sizeof(gname), "%d", i);
         if ((gid = H5Gopen2(fid, gname, H5P_DEFAULT)) < 0)
             TEST_ERROR;
 
@@ -988,7 +988,7 @@ check_link_iteration_tags(void)
     /* Create many datasets in root group */
     for (i = 0; i < 500; i++) {
 
-        HDsprintf(dsetname, "Dset %d", i);
+        HDsnprintf(dsetname, sizeof(dsetname), "Dset %d", i);
         if ((did = H5Dcreate2(fid, dsetname, H5T_NATIVE_UCHAR, sid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) <
             0)
             TEST_ERROR;
@@ -1151,7 +1151,7 @@ check_dense_attribute_tags(void)
 
     for (i = 0; i < 50; i++) {
 
-        HDsprintf(attrname, "attr %d", i);
+        HDsnprintf(attrname, sizeof(attrname), "attr %d", i);
         if ((aid = H5Acreate2(did, attrname, H5T_NATIVE_UINT, sid, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
         if (H5Awrite(aid, H5T_NATIVE_UINT, &i) < 0)
diff --git a/test/cork.c b/test/cork.c
index 7628d28..53d9065 100644
--- a/test/cork.c
+++ b/test/cork.c
@@ -396,7 +396,7 @@ verify_obj_dset_cork(hbool_t swmr)
 
     /* Attach 8 attributes to the dataset */
     for (i = 0; i < 8; i++) {
-        HDsprintf(attrname, "attr %d", i);
+        HDsnprintf(attrname, sizeof(attrname), "attr %d", i);
         if ((aid = H5Acreate2(did2, attrname, H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
         if (H5Awrite(aid, H5T_NATIVE_INT, &i) < 0)
@@ -864,7 +864,7 @@ verify_group_cork(hbool_t swmr)
 
     /* Attach 8 attributes to the third group: GRP3 */
     for (i = 0; i < 8; i++) {
-        HDsprintf(attrname, "attr %d", i);
+        HDsnprintf(attrname, sizeof(attrname), "attr %d", i);
         if ((aid = H5Acreate2(gid3, attrname, H5T_NATIVE_UINT, sid, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
         if (H5Awrite(aid, H5T_NATIVE_UINT, &i) < 0)
@@ -1081,7 +1081,7 @@ verify_named_cork(hbool_t swmr)
 
     /* Attach 8 attributes to datatype: DT3 */
     for (i = 0; i < 8; i++) {
-        HDsprintf(attrname, "attr %d", i);
+        HDsnprintf(attrname, sizeof(attrname), "attr %d", i);
         if ((aid = H5Acreate2(tid3, attrname, H5T_NATIVE_UINT, sid, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
         if (H5Awrite(aid, H5T_NATIVE_UINT, &i) < 0)
diff --git a/test/dtypes.c b/test/dtypes.c
index 218c019..f322d03 100644
--- a/test/dtypes.c
+++ b/test/dtypes.c
@@ -2322,7 +2322,7 @@ test_compound_11(void)
         ((big_t *)buf)[u].s1 = (char *)HDmalloc((size_t)32);
         if (!((big_t *)buf)[u].s1)
             TEST_ERROR;
-        HDsprintf(((big_t *)buf)[u].s1, "%u", (unsigned)u);
+        HDsnprintf(((big_t *)buf)[u].s1, 32, "%u", (unsigned)u);
     } /* end for */
 
     /* Make copy of buffer before conversion */
diff --git a/test/fheap.c b/test/fheap.c
index 01de37f..7fec567 100644
--- a/test/fheap.c
+++ b/test/fheap.c
@@ -7669,7 +7669,7 @@ test_man_incr_insert_remove(hid_t fapl, H5HF_create_t *cparam, fheap_test_param_
             if (H5HF_remove(fh, heap_id[j]) < 0)
                 FAIL_STACK_ERROR;
 
-            HDsprintf(obj2.b, "%s%2d", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", j);
+            HDsnprintf(obj2.b, sizeof(obj2.b), "%s%2d", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", j);
             if (H5HF_insert(fh, (sizeof(obj2)), &obj2, heap_id[j]) < 0)
                 FAIL_STACK_ERROR;
         } /* end for */
@@ -7680,7 +7680,7 @@ test_man_incr_insert_remove(hid_t fapl, H5HF_create_t *cparam, fheap_test_param_
 
         /* Insert object */
         HDmemset(heap_id[i], 0, id_len);
-        HDsprintf(obj1.b, "%s%2d", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", i);
+        HDsnprintf(obj1.b, sizeof(obj1.b), "%s%2d", "ABCDEFGHIJKLMNOPQRSTUVWXYZ", i);
         if (H5HF_insert(fh, (sizeof(obj1)), &obj1, heap_id[i]) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
diff --git a/test/filter_plugin.c b/test/filter_plugin.c
index abbcc26..4dcf74a 100644
--- a/test/filter_plugin.c
+++ b/test/filter_plugin.c
@@ -847,7 +847,7 @@ test_creating_groups_using_plugins(hid_t fid)
     for (i = 0; i < N_SUBGROUPS; i++) {
         char *sp = subgroup_name;
 
-        sp += HDsprintf(subgroup_name, SUBGROUP_PREFIX);
+        sp += HDsnprintf(subgroup_name, sizeof(subgroup_name), SUBGROUP_PREFIX);
         HDsprintf(sp, "%d", i);
 
         if ((sub_gid = H5Gcreate2(gid, subgroup_name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
@@ -906,7 +906,7 @@ test_opening_groups_using_plugins(hid_t fid)
     for (i = 0; i < N_SUBGROUPS; i++) {
         char *sp = subgroup_name;
 
-        sp += HDsprintf(subgroup_name, SUBGROUP_PREFIX);
+        sp += HDsnprintf(subgroup_name, sizeof(subgroup_name), SUBGROUP_PREFIX);
         HDsprintf(sp, "%d", i);
 
         if ((sub_gid = H5Gopen2(gid, subgroup_name, H5P_DEFAULT)) < 0)
@@ -1015,7 +1015,7 @@ test_path_api_calls(void)
 
     /* Add a bunch of paths to the path table */
     for (u = 0; u < n_starting_paths; u++) {
-        HDsprintf(path, "a_path_%u", u);
+        HDsnprintf(path, sizeof(path), "a_path_%u", u);
         if (H5PLappend(path) < 0) {
             HDfprintf(stderr, "    at %u: %s\n", u, path);
             TEST_ERROR;
@@ -1081,7 +1081,7 @@ test_path_api_calls(void)
     /* Get path at the last index */
     if ((path_len = H5PLget(n_starting_paths - 1, path, 256)) <= 0)
         TEST_ERROR;
-    HDsprintf(temp_name, "a_path_%u", n_starting_paths - 1);
+    HDsnprintf(temp_name, sizeof(temp_name), "a_path_%u", n_starting_paths - 1);
     if (HDstrcmp(path, temp_name) != 0) {
         HDfprintf(stderr, "    get %u: %s\n", n_starting_paths - 1, path);
         TEST_ERROR;
@@ -1135,7 +1135,7 @@ test_path_api_calls(void)
     TESTING("    prepend");
 
     /* Prepend one path */
-    HDsprintf(path, "a_path_%d", n_starting_paths + 1);
+    HDsnprintf(path, sizeof(path), "a_path_%d", n_starting_paths + 1);
     if (H5PLprepend(path) < 0) {
         HDfprintf(stderr, "    prepend %u: %s\n", n_starting_paths + 1, path);
         TEST_ERROR;
@@ -1158,7 +1158,7 @@ test_path_api_calls(void)
     /* Verify that the path was inserted at index zero */
     if (H5PLget(0, path, 256) <= 0)
         TEST_ERROR;
-    HDsprintf(temp_name, "a_path_%d", n_starting_paths + 1);
+    HDsnprintf(temp_name, sizeof(temp_name), "a_path_%d", n_starting_paths + 1);
     if (HDstrcmp(path, temp_name) != 0) {
         HDfprintf(stderr, "    get 0: %s\n", path);
         TEST_ERROR;
@@ -1173,7 +1173,7 @@ test_path_api_calls(void)
     TESTING("    replace");
 
     /* Replace one path at index 1 */
-    HDsprintf(path, "a_path_%u", n_starting_paths + 4);
+    HDsnprintf(path, sizeof(path), "a_path_%u", n_starting_paths + 4);
     if (H5PLreplace(path, 1) < 0) {
         HDfprintf(stderr, "    replace 1: %s\n", path);
         TEST_ERROR;
@@ -1192,7 +1192,7 @@ test_path_api_calls(void)
     /* Check path at index 0 */
     if (H5PLget(0, path, 256) <= 0)
         TEST_ERROR;
-    HDsprintf(temp_name, "a_path_%u", n_starting_paths + 1);
+    HDsnprintf(temp_name, sizeof(temp_name), "a_path_%u", n_starting_paths + 1);
     if (HDstrcmp(path, temp_name) != 0) {
         HDfprintf(stderr, "    get 0: %s\n", path);
         TEST_ERROR;
@@ -1240,7 +1240,7 @@ test_path_api_calls(void)
     TESTING("    insert");
 
     /* Insert one path at index 3*/
-    HDsprintf(path, "a_path_%d", n_starting_paths + 5);
+    HDsnprintf(path, sizeof(path), "a_path_%d", n_starting_paths + 5);
     if (H5PLinsert(path, 3) < 0) {
         HDfprintf(stderr, "    insert 3: %s\n", path);
         TEST_ERROR;
diff --git a/test/h5test.c b/test/h5test.c
index ac15043..f39825c 100644
--- a/test/h5test.c
+++ b/test/h5test.c
@@ -355,7 +355,7 @@ h5_reset(void)
          * Cause the library to emit some diagnostics early so they don't
          * interfere with other formatted output.
          */
-        HDsprintf(filename, "/tmp/h5emit-%05d.h5", HDgetpid());
+        HDsnprintf(filename, sizeof(filename), "/tmp/h5emit-%05d.h5", HDgetpid());
         H5E_BEGIN_TRY
         {
             hid_t file = H5Fcreate(filename, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
diff --git a/test/hyperslab.c b/test/hyperslab.c
index 36e6b65..b816aae 100644
--- a/test/hyperslab.c
+++ b/test/hyperslab.c
@@ -163,19 +163,19 @@ test_fill(size_t nx, size_t ny, size_t nz, size_t di, size_t dj, size_t dk, size
         if (0 == ny) {
             ndims = 1;
             ny = nz = 1;
-            HDsprintf(dim, "%lu", (unsigned long)nx);
+            HDsnprintf(dim, sizeof(dim), "%lu", (unsigned long)nx);
         } /* end if */
         else {
             ndims = 2;
             nz    = 1;
-            HDsprintf(dim, "%lux%lu", (unsigned long)nx, (unsigned long)ny);
+            HDsnprintf(dim, sizeof(dim), "%lux%lu", (unsigned long)nx, (unsigned long)ny);
         } /* end else */
     }     /* end if */
     else {
         ndims = 3;
-        HDsprintf(dim, "%lux%lux%lu", (unsigned long)nx, (unsigned long)ny, (unsigned long)nz);
+        HDsnprintf(dim, sizeof(dim), "%lux%lux%lu", (unsigned long)nx, (unsigned long)ny, (unsigned long)nz);
     } /* end else */
-    HDsprintf(s, "Testing hyperslab fill %-11s variable hyperslab", dim);
+    HDsnprintf(s, sizeof(s), "Testing hyperslab fill %-11s variable hyperslab", dim);
     HDprintf("%-70s", s);
     HDfflush(stdout);
 
@@ -321,17 +321,17 @@ test_copy(int mode, size_t nx, size_t ny, size_t nz, size_t di, size_t dj, size_
         if (0 == ny) {
             ndims = 1;
             ny = nz = 1;
-            HDsprintf(dim, "%lu", (unsigned long)nx);
+            HDsnprintf(dim, sizeof(dim), "%lu", (unsigned long)nx);
         } /* end if */
         else {
             ndims = 2;
             nz    = 1;
-            HDsprintf(dim, "%lux%lu", (unsigned long)nx, (unsigned long)ny);
+            HDsnprintf(dim, sizeof(dim), "%lux%lu", (unsigned long)nx, (unsigned long)ny);
         } /* end else */
     }     /* end if */
     else {
         ndims = 3;
-        HDsprintf(dim, "%lux%lux%lu", (unsigned long)nx, (unsigned long)ny, (unsigned long)nz);
+        HDsnprintf(dim, sizeof(dim), "%lux%lux%lu", (unsigned long)nx, (unsigned long)ny, (unsigned long)nz);
     } /* end else */
 
     switch (mode) {
@@ -364,7 +364,7 @@ test_copy(int mode, size_t nx, size_t ny, size_t nz, size_t di, size_t dj, size_
             HDabort();
     } /* end switch */
 
-    HDsprintf(s, "Testing hyperslab copy %-11s %s", dim, sub);
+    HDsnprintf(s, sizeof(s), "Testing hyperslab copy %-11s %s", dim, sub);
     HDprintf("%-70s", s);
     HDfflush(stdout);
 
@@ -618,15 +618,15 @@ test_multifill(size_t nx)
     s[0] = '\0';
     for (i = 0; i < nx; i++) {
         if (dst[i].left != 3333333)
-            HDsprintf(s, "bad dst[%lu].left", (unsigned long)i);
+            HDsnprintf(s, sizeof(s), "bad dst[%lu].left", (unsigned long)i);
         else if (!H5_DBL_ABS_EQUAL(dst[i].mid, fill.mid))
             /* Check if two DOUBLE values are equal.  If their difference
              * is smaller than the EPSILON value for double, they are
              * considered equal. See the definition in h5test.h.
              */
-            HDsprintf(s, "bad dst[%lu].mid", (unsigned long)i);
+            HDsnprintf(s, sizeof(s), "bad dst[%lu].mid", (unsigned long)i);
         else if (dst[i].right != 4444444)
-            HDsprintf(s, "bad dst[%lu].right", (unsigned long)i);
+            HDsnprintf(s, sizeof(s), "bad dst[%lu].right", (unsigned long)i);
         if (s[0]) {
             H5_FAILED();
             if (!HDisatty(1)) {
@@ -771,7 +771,8 @@ test_transpose(size_t nx, size_t ny)
     char    s[256];
     hsize_t i, j;
 
-    HDsprintf(s, "Testing 2d transpose by stride %4lux%-lud", (unsigned long)nx, (unsigned long)ny);
+    HDsnprintf(s, sizeof(s), "Testing 2d transpose by stride %4lux%-lud", (unsigned long)nx,
+               (unsigned long)ny);
     HDprintf("%-70s", s);
     HDfflush(stdout);
 
@@ -869,8 +870,8 @@ test_sub_super(size_t nx, size_t ny)
     hsize_t  i, j;
     char     s[256];
 
-    HDsprintf(s, "Testing image sampling %4lux%-4lu to %4lux%-4lu ", (unsigned long)(2 * nx),
-              (unsigned long)(2 * ny), (unsigned long)nx, (unsigned long)ny);
+    HDsnprintf(s, sizeof(s), "Testing image sampling %4lux%-4lu to %4lux%-4lu ", (unsigned long)(2 * nx),
+               (unsigned long)(2 * ny), (unsigned long)nx, (unsigned long)ny);
     HDprintf("%-70s", s);
     HDfflush(stdout);
 
@@ -919,8 +920,8 @@ test_sub_super(size_t nx, size_t ny)
      * Test replicating pixels to produce an image twice as large in each
      * dimension.
      */
-    HDsprintf(s, "Testing image sampling %4lux%-4lu to %4lux%-4lu ", (unsigned long)nx, (unsigned long)ny,
-              (unsigned long)(2 * nx), (unsigned long)(2 * ny));
+    HDsnprintf(s, sizeof(s), "Testing image sampling %4lux%-4lu to %4lux%-4lu ", (unsigned long)nx,
+               (unsigned long)ny, (unsigned long)(2 * nx), (unsigned long)(2 * ny));
     HDprintf("%-70s", s);
     HDfflush(stdout);
 
@@ -946,17 +947,17 @@ test_sub_super(size_t nx, size_t ny)
     for (i = 0; i < nx; i++) {
         for (j = 0; j < ny; j++) {
             if (half[i * ny + j] != twice[4 * i * ny + 2 * j])
-                HDsprintf(s, "half[%lu][%lu] != twice[%lu][%lu]", (unsigned long)i, (unsigned long)j,
-                          (unsigned long)i * 2, (unsigned long)j * 2);
+                HDsnprintf(s, sizeof(s), "half[%lu][%lu] != twice[%lu][%lu]", (unsigned long)i,
+                           (unsigned long)j, (unsigned long)i * 2, (unsigned long)j * 2);
             else if (half[i * ny + j] != twice[4 * i * ny + 2 * j + 1])
-                HDsprintf(s, "half[%lu][%lu] != twice[%lu][%lu]", (unsigned long)i, (unsigned long)j,
-                          (unsigned long)i * 2, (unsigned long)j * 2 + 1);
+                HDsnprintf(s, sizeof(s), "half[%lu][%lu] != twice[%lu][%lu]", (unsigned long)i,
+                           (unsigned long)j, (unsigned long)i * 2, (unsigned long)j * 2 + 1);
             else if (half[i * ny + j] != twice[(2 * i + 1) * 2 * ny + 2 * j])
-                HDsprintf(s, "half[%lu][%lu] != twice[%lu][%lu]", (unsigned long)i, (unsigned long)j,
-                          (unsigned long)i * 2 + 1, (unsigned long)j * 2);
+                HDsnprintf(s, sizeof(s), "half[%lu][%lu] != twice[%lu][%lu]", (unsigned long)i,
+                           (unsigned long)j, (unsigned long)i * 2 + 1, (unsigned long)j * 2);
             else if (half[i * ny + j] != twice[(2 * i + 1) * 2 * ny + 2 * j + 1])
-                HDsprintf(s, "half[%lu][%lu] != twice[%lu][%lu]", (unsigned long)i, (unsigned long)j,
-                          (unsigned long)i * 2 + 1, (unsigned long)j * 2 + 1);
+                HDsnprintf(s, sizeof(s), "half[%lu][%lu] != twice[%lu][%lu]", (unsigned long)i,
+                           (unsigned long)j, (unsigned long)i * 2 + 1, (unsigned long)j * 2 + 1);
             if (s[0]) {
                 H5_FAILED();
                 if (!HDisatty(1)) {
@@ -1014,7 +1015,7 @@ test_array_fill(size_t lo, size_t hi)
     size_t u, v, w;              /* Local index variables        */
     char   s[256];
 
-    HDsprintf(s, "array filling %4lu-%-4lu elements", (unsigned long)lo, (unsigned long)hi);
+    HDsnprintf(s, sizeof(s), "array filling %4lu-%-4lu elements", (unsigned long)lo, (unsigned long)hi);
     TESTING(s);
 
     /* Initialize */
@@ -1078,8 +1079,8 @@ test_array_offset_n_calc(size_t n, size_t x, size_t y, size_t z)
     hsize_t  new_coords[ARRAY_OFFSET_NDIMS]; /* X, Y & X coordinates of offset */
     char     s[256];
 
-    HDsprintf(s, "array offset %4lux%4lux%4lu elements", (unsigned long)z, (unsigned long)y,
-              (unsigned long)x);
+    HDsnprintf(s, sizeof(s), "array offset %4lux%4lux%4lu elements", (unsigned long)z, (unsigned long)y,
+               (unsigned long)x);
     TESTING(s);
 
     /* Initialize */
diff --git a/test/istore.c b/test/istore.c
index f198aad..144355e 100644
--- a/test/istore.c
+++ b/test/istore.c
@@ -271,20 +271,21 @@ test_extend(hid_t f, const char *prefix, size_t nx, size_t ny, size_t nz)
         if (!ny) {
             ndims = 1;
             ny = nz = 1;
-            HDsprintf(dims, "%lu", (unsigned long)nx);
+            HDsnprintf(dims, sizeof(dims), "%lu", (unsigned long)nx);
         }
         else {
             ndims = 2;
             nz    = 1;
-            HDsprintf(dims, "%lux%lu", (unsigned long)nx, (unsigned long)ny);
+            HDsnprintf(dims, sizeof(dims), "%lux%lu", (unsigned long)nx, (unsigned long)ny);
         }
     }
     else {
         ndims = 3;
-        HDsprintf(dims, "%lux%lux%lu", (unsigned long)nx, (unsigned long)ny, (unsigned long)nz);
+        HDsnprintf(dims, sizeof(dims), "%lux%lux%lu", (unsigned long)nx, (unsigned long)ny,
+                   (unsigned long)nz);
     }
 
-    HDsprintf(s, "istore extend: %s", dims);
+    HDsnprintf(s, sizeof(s), "istore extend: %s", dims);
     TESTING(s);
     buf   = (uint8_t *)HDmalloc(nx * ny * nz);
     check = (uint8_t *)HDmalloc(nx * ny * nz);
@@ -298,7 +299,7 @@ test_extend(hid_t f, const char *prefix, size_t nx, size_t ny, size_t nz)
     max_corner[2] = 0;
 
     /* Build the new empty object */
-    HDsprintf(name, "%s_%s", prefix, dims);
+    HDsnprintf(name, sizeof(name), "%s_%s", prefix, dims);
     if ((dataset = new_object(f, name, ndims, whole_size, whole_size)) < 0) {
         HDfprintf(stderr, "    Cannot create %u-d object `%s'\n", ndims, name);
         goto error;
@@ -468,20 +469,21 @@ test_sparse(hid_t f, const char *prefix, size_t nblocks, size_t nx, size_t ny, s
         if (!ny) {
             ndims = 1;
             ny = nz = 1;
-            HDsprintf(dims, "%lu", (unsigned long)nx);
+            HDsnprintf(dims, sizeof(dims), "%lu", (unsigned long)nx);
         }
         else {
             ndims = 2;
             nz    = 1;
-            HDsprintf(dims, "%lux%lu", (unsigned long)nx, (unsigned long)ny);
+            HDsnprintf(dims, sizeof(dims), "%lux%lu", (unsigned long)nx, (unsigned long)ny);
         }
     }
     else {
         ndims = 3;
-        HDsprintf(dims, "%lux%lux%lu", (unsigned long)nx, (unsigned long)ny, (unsigned long)nz);
+        HDsnprintf(dims, sizeof(dims), "%lux%lux%lu", (unsigned long)nx, (unsigned long)ny,
+                   (unsigned long)nz);
     }
 
-    HDsprintf(s, "istore sparse: %s", dims);
+    HDsnprintf(s, sizeof(s), "istore sparse: %s", dims);
     TESTING(s);
     if (skip_test) {
         SKIPPED();
@@ -500,7 +502,7 @@ test_sparse(hid_t f, const char *prefix, size_t nblocks, size_t nx, size_t ny, s
     size[2] = nz;
 
     /* Build the new empty object */
-    HDsprintf(name, "%s_%s", prefix, dims);
+    HDsnprintf(name, sizeof(name), "%s_%s", prefix, dims);
     if ((dataset = new_object(f, name, ndims, whole_size, chunk_dims)) < 0) {
         HDprintf("    Cannot create %u-d object `%s'\n", ndims, name);
         goto error;
diff --git a/test/lheap.c b/test/lheap.c
index 1c6a6df..c9c6ca9 100644
--- a/test/lheap.c
+++ b/test/lheap.c
@@ -97,7 +97,7 @@ main(void)
         goto error;
     }
     for (i = 0; i < NOBJS; i++) {
-        HDsprintf(buf, "%03d-", i);
+        HDsnprintf(buf, sizeof(buf), "%03d-", i);
         for (j = 4; j < i; j++)
             buf[j] = (char)('0' + j % 10);
         if (j > 4)
@@ -137,7 +137,7 @@ main(void)
         goto error;
     }
     for (i = 0; i < NOBJS; i++) {
-        HDsprintf(buf, "%03d-", i);
+        HDsnprintf(buf, sizeof(buf), "%03d-", i);
         for (j = 4; j < i; j++)
             buf[j] = (char)('0' + j % 10);
         if (j > 4)
diff --git a/test/mf.c b/test/mf.c
index ce9d667..bed92e3 100644
--- a/test/mf.c
+++ b/test/mf.c
@@ -6586,22 +6586,22 @@ error:
         memb_map[H5FD_MEM_DRAW]  = H5FD_MEM_DRAW;                                                            \
         memb_map[H5FD_MEM_GHEAP] = H5FD_MEM_GHEAP;                                                           \
         memb_map[H5FD_MEM_LHEAP] = H5FD_MEM_LHEAP;                                                           \
-        HDsprintf(sv[H5FD_MEM_SUPER], "%%s-%c.h5", 's');                                                     \
+        HDsnprintf(sv[H5FD_MEM_SUPER], 64, "%%s-%c.h5", 's');                                                \
         memb_name[H5FD_MEM_SUPER] = sv[H5FD_MEM_SUPER];                                                      \
         memb_addr[H5FD_MEM_SUPER] = 0;                                                                       \
-        HDsprintf(sv[H5FD_MEM_BTREE], "%%s-%c.h5", 'b');                                                     \
+        HDsnprintf(sv[H5FD_MEM_BTREE], 64, "%%s-%c.h5", 'b');                                                \
         memb_name[H5FD_MEM_BTREE] = sv[H5FD_MEM_BTREE];                                                      \
         memb_addr[H5FD_MEM_BTREE] = HADDR_MAX / 6;                                                           \
-        HDsprintf(sv[H5FD_MEM_DRAW], "%%s-%c.h5", 'r');                                                      \
+        HDsnprintf(sv[H5FD_MEM_DRAW], 64, "%%s-%c.h5", 'r');                                                 \
         memb_name[H5FD_MEM_DRAW] = sv[H5FD_MEM_DRAW];                                                        \
         memb_addr[H5FD_MEM_DRAW] = HADDR_MAX / 3;                                                            \
-        HDsprintf(sv[H5FD_MEM_GHEAP], "%%s-%c.h5", 'g');                                                     \
+        HDsnprintf(sv[H5FD_MEM_GHEAP], 64, "%%s-%c.h5", 'g');                                                \
         memb_name[H5FD_MEM_GHEAP] = sv[H5FD_MEM_GHEAP];                                                      \
         memb_addr[H5FD_MEM_GHEAP] = HADDR_MAX / 2;                                                           \
-        HDsprintf(sv[H5FD_MEM_LHEAP], "%%s-%c.h5", 'l');                                                     \
+        HDsnprintf(sv[H5FD_MEM_LHEAP], 64, "%%s-%c.h5", 'l');                                                \
         memb_name[H5FD_MEM_LHEAP] = sv[H5FD_MEM_LHEAP];                                                      \
         memb_addr[H5FD_MEM_LHEAP] = HADDR_MAX * 2 / 3;                                                       \
-        HDsprintf(sv[H5FD_MEM_OHDR], "%%s-%c.h5", 'o');                                                      \
+        HDsnprintf(sv[H5FD_MEM_OHDR], 64, "%%s-%c.h5", 'o');                                                 \
         memb_name[H5FD_MEM_OHDR] = sv[H5FD_MEM_OHDR];                                                        \
         memb_addr[H5FD_MEM_OHDR] = HADDR_MAX * 5 / 6;                                                        \
     }
diff --git a/test/objcopy.c b/test/objcopy.c
index cc8f428..62fb22e 100644
--- a/test/objcopy.c
+++ b/test/objcopy.c
@@ -646,7 +646,7 @@ test_copy_attach_attributes(hid_t loc_id, hid_t type_id)
         goto done;
 
     for (u = 0; u < num_attributes_g; u++) {
-        HDsprintf(attr_name, "%u attr", u);
+        HDsnprintf(attr_name, sizeof(attr_name), "%u attr", u);
 
         /* Set attribute data */
         attr_data[0] = (int)(100 * u);
@@ -715,7 +715,7 @@ test_copy_attach_paired_attributes(hid_t loc_id, hid_t loc_id2, hid_t type_id)
         goto done;
 
     for (u = 0; u < num_attributes_g; u++) {
-        HDsprintf(attr_name, "%u attr", u);
+        HDsnprintf(attr_name, sizeof(attr_name), "%u attr", u);
 
         /* Set attribute data */
         attr_data[0] = (int)(100 * u);
@@ -7933,17 +7933,17 @@ test_copy_group_deep(hid_t fcpl_src, hid_t fcpl_dst, hid_t src_fapl, hid_t dst_f
 
     /* create nested sub-groups & datasets */
     for (i = 0; i < NUM_SUB_GROUPS; i++) {
-        HDsprintf(objname, "Group #%d", i);
+        HDsnprintf(objname, sizeof(objname), "Group #%d", i);
         if ((gid_sub = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
 
         for (j = 0; j < NUM_SUB_GROUPS; j++) {
-            HDsprintf(objname, "Group #%d", j);
+            HDsnprintf(objname, sizeof(objname), "Group #%d", j);
             if ((gid_sub2 = H5Gcreate2(gid_sub, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
                 TEST_ERROR;
 
             for (k = 0; k < NUM_DATASETS; k++) {
-                HDsprintf(objname, "Dataset #%d", k);
+                HDsnprintf(objname, sizeof(objname), "Dataset #%d", k);
 
                 /* add a dataset to the group */
                 if ((did = H5Dcreate2(gid_sub2, objname, H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT,
@@ -8222,12 +8222,12 @@ test_copy_group_wide_loop(hid_t fcpl_src, hid_t fcpl_dst, hid_t src_fapl, hid_t
 
     /* create wide sub-group hierarchy, with multiple links to higher groups */
     for (u = 0; u < NUM_WIDE_LOOP_GROUPS; u++) {
-        HDsprintf(objname, "%s-%u", NAME_GROUP_SUB, u);
+        HDsnprintf(objname, sizeof(objname), "%s-%u", NAME_GROUP_SUB, u);
         if ((gid_sub = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
 
         for (v = 0; v < NUM_WIDE_LOOP_GROUPS; v++) {
-            HDsprintf(objname, "%s-%u", NAME_GROUP_SUB_SUB2, v);
+            HDsnprintf(objname, sizeof(objname), "%s-%u", NAME_GROUP_SUB_SUB2, v);
             if ((gid_sub2 = H5Gcreate2(gid_sub, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
                 FAIL_STACK_ERROR;
 
diff --git a/test/objcopy_ref.c b/test/objcopy_ref.c
index adc1a84..d10adf6 100644
--- a/test/objcopy_ref.c
+++ b/test/objcopy_ref.c
@@ -509,7 +509,7 @@ test_copy_attach_attributes(hid_t loc_id, hid_t type_id)
         goto done;
 
     for (u = 0; u < num_attributes_g; u++) {
-        HDsprintf(attr_name, "%u attr", u);
+        HDsnprintf(attr_name, sizeof(attr_name), "%u attr", u);
 
         /* Set attribute data */
         attr_data[0] = (int)(100 * u);
diff --git a/test/ohdr.c b/test/ohdr.c
index 6b31334..dc0497f 100644
--- a/test/ohdr.c
+++ b/test/ohdr.c
@@ -1883,7 +1883,7 @@ main(void)
             /* Display info about testing */
             low_string  = h5_get_version_string(low);
             high_string = h5_get_version_string(high);
-            HDsprintf(msg, "Using file format version: (%s, %s)", low_string, high_string);
+            HDsnprintf(msg, sizeof(msg), "Using file format version: (%s, %s)", low_string, high_string);
             HDputs(msg);
 
             /* test on object continuation block */
diff --git a/test/stab.c b/test/stab.c
index d08ebca..b4c92a4 100644
--- a/test/stab.c
+++ b/test/stab.c
@@ -219,8 +219,9 @@ test_long(hid_t fcpl, hid_t fapl, hbool_t new_format)
     for (i = 0; i < LONG_NAME_LEN; i++)
         name1[i] = (char)('A' + i % 26);
     name1[LONG_NAME_LEN - 1] = '\0';
-    name2                    = (char *)HDmalloc((size_t)((2 * LONG_NAME_LEN) + 2));
-    HDsprintf(name2, "%s/%s", name1, name1);
+    size_t name2Len          = (2 * LONG_NAME_LEN) + 2;
+    name2                    = (char *)HDmalloc(name2Len);
+    HDsnprintf(name2, name2Len, "%s/%s", name1, name1);
 
     /* Create groups */
     if ((g1 = H5Gcreate2(fid, name1, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
@@ -310,7 +311,7 @@ test_large(hid_t fcpl, hid_t fapl, hbool_t new_format)
         if (H5G__has_stab_test(cwg) != FALSE)
             TEST_ERROR;
     for (i = 0; i < LARGE_NOBJS; i++) {
-        HDsprintf(name, "%05d%05d", (HDrandom() % 100000), i);
+        HDsnprintf(name, sizeof(name), "%05d%05d", (HDrandom() % 100000), i);
         if ((dir = H5Gcreate2(cwg, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
         if (H5Gclose(dir) < 0)
@@ -452,7 +453,7 @@ lifecycle(hid_t fcpl, hid_t fapl2)
         TEST_ERROR;
 
     /* Create first "bottom" group */
-    HDsprintf(objname, LIFECYCLE_BOTTOM_GROUP, (unsigned)0);
+    HDsnprintf(objname, sizeof(objname), LIFECYCLE_BOTTOM_GROUP, (unsigned)0);
     if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         TEST_ERROR;
 
@@ -475,7 +476,7 @@ lifecycle(hid_t fcpl, hid_t fapl2)
     /* Create several more bottom groups, to push the top group almost to a symbol table */
     /* (Start counting at '1', since we've already created one bottom group */
     for (u = 1; u < LIFECYCLE_MAX_COMPACT; u++) {
-        HDsprintf(objname, LIFECYCLE_BOTTOM_GROUP, u);
+        HDsnprintf(objname, sizeof(objname), LIFECYCLE_BOTTOM_GROUP, u);
         if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
 
@@ -511,7 +512,7 @@ lifecycle(hid_t fcpl, hid_t fapl2)
         TEST_ERROR;
 
     /* Create one more "bottom" group, which should push top group into using a symbol table */
-    HDsprintf(objname, LIFECYCLE_BOTTOM_GROUP, u);
+    HDsnprintf(objname, sizeof(objname), LIFECYCLE_BOTTOM_GROUP, u);
     if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         TEST_ERROR;
 
@@ -545,7 +546,7 @@ lifecycle(hid_t fcpl, hid_t fapl2)
 
     /* Unlink objects from top group */
     while (u >= LIFECYCLE_MIN_DENSE) {
-        HDsprintf(objname, LIFECYCLE_BOTTOM_GROUP, u);
+        HDsnprintf(objname, sizeof(objname), LIFECYCLE_BOTTOM_GROUP, u);
 
         if (H5Ldelete(gid, objname, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
@@ -562,7 +563,7 @@ lifecycle(hid_t fcpl, hid_t fapl2)
         TEST_ERROR;
 
     /* Unlink one more object from the group, which should transform back to using links */
-    HDsprintf(objname, LIFECYCLE_BOTTOM_GROUP, u);
+    HDsnprintf(objname, sizeof(objname), LIFECYCLE_BOTTOM_GROUP, u);
     if (H5Ldelete(gid, objname, H5P_DEFAULT) < 0)
         FAIL_STACK_ERROR;
     u--;
@@ -576,11 +577,11 @@ lifecycle(hid_t fcpl, hid_t fapl2)
         TEST_ERROR;
 
     /* Unlink last two objects from top group */
-    HDsprintf(objname, LIFECYCLE_BOTTOM_GROUP, u);
+    HDsnprintf(objname, sizeof(objname), LIFECYCLE_BOTTOM_GROUP, u);
     if (H5Ldelete(gid, objname, H5P_DEFAULT) < 0)
         FAIL_STACK_ERROR;
     u--;
-    HDsprintf(objname, LIFECYCLE_BOTTOM_GROUP, u);
+    HDsnprintf(objname, sizeof(objname), LIFECYCLE_BOTTOM_GROUP, u);
     if (H5Ldelete(gid, objname, H5P_DEFAULT) < 0)
         FAIL_STACK_ERROR;
 
@@ -841,7 +842,7 @@ read_old(void)
 
     /* Create a bunch of objects in the group */
     for (u = 0; u < READ_OLD_NGROUPS; u++) {
-        HDsprintf(objname, "Group %u", u);
+        HDsnprintf(objname, sizeof(objname), "Group %u", u);
         if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
 
@@ -865,7 +866,7 @@ read_old(void)
 
     /* Delete new objects from old group */
     for (u = 0; u < READ_OLD_NGROUPS; u++) {
-        HDsprintf(objname, "Group %u", u);
+        HDsnprintf(objname, sizeof(objname), "Group %u", u);
         if (H5Ldelete(gid, objname, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -977,7 +978,7 @@ no_compact(hid_t fcpl, hid_t fapl2)
         TEST_ERROR;
 
     /* Create first "bottom" group */
-    HDsprintf(objname, NO_COMPACT_BOTTOM_GROUP, (unsigned)0);
+    HDsnprintf(objname, sizeof(objname), NO_COMPACT_BOTTOM_GROUP, (unsigned)0);
     if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         TEST_ERROR;
 
@@ -998,7 +999,7 @@ no_compact(hid_t fcpl, hid_t fapl2)
         TEST_ERROR;
 
     /* Unlink object from top group */
-    HDsprintf(objname, NO_COMPACT_BOTTOM_GROUP, (unsigned)0);
+    HDsnprintf(objname, sizeof(objname), NO_COMPACT_BOTTOM_GROUP, (unsigned)0);
     if (H5Ldelete(gid, objname, H5P_DEFAULT) < 0)
         FAIL_STACK_ERROR;
 
diff --git a/test/swmr_common.c b/test/swmr_common.c
index b359bc6..9063ddd 100644
--- a/test/swmr_common.c
+++ b/test/swmr_common.c
@@ -162,6 +162,9 @@ create_symbol_datatype(void)
  *              Buffer for the created name.  Must be pre-allocated.
  *              Since the name is formulaic, this isn't considered an issue.
  *
+ *              size_t name_buf_length
+ *              The length in bytes of the name_buf buffer
+ *
  *              unsigned level
  *              The dataset's level
  *
@@ -175,11 +178,11 @@ create_symbol_datatype(void)
  *-------------------------------------------------------------------------
  */
 int
-generate_name(char *name_buf, unsigned level, unsigned count)
+generate_name(char *name_buf, size_t name_buf_length, unsigned level, unsigned count)
 {
     HDassert(name_buf);
 
-    HDsprintf(name_buf, "%u-%04u", level, count);
+    HDsnprintf(name_buf, name_buf_length, "%u-%04u", level, count);
 
     return 0;
 } /* end generate_name() */
@@ -206,7 +209,7 @@ generate_symbols(void)
         for (v = 0; v < symbol_count[u]; v++) {
             char name_buf[64];
 
-            generate_name(name_buf, u, v);
+            generate_name(name_buf, sizeof(name_buf), u, v);
             symbol_info[u][v].name     = HDstrdup(name_buf);
             symbol_info[u][v].dsid     = -1;
             symbol_info[u][v].nrecords = 0;
diff --git a/test/swmr_common.h b/test/swmr_common.h
index d0d829d..5fcf923 100644
--- a/test/swmr_common.h
+++ b/test/swmr_common.h
@@ -66,10 +66,10 @@ extern "C" {
 
 H5TEST_DLL symbol_info_t *choose_dataset(void);
 H5TEST_DLL hid_t          create_symbol_datatype(void);
-H5TEST_DLL int            generate_name(char *name_buf, unsigned level, unsigned count);
-H5TEST_DLL int            generate_symbols(void);
-H5TEST_DLL int            shutdown_symbols(void);
-H5TEST_DLL int            print_metadata_retries_info(hid_t fid);
+H5TEST_DLL int generate_name(char *name_buf, size_t name_buf_length, unsigned level, unsigned count);
+H5TEST_DLL int generate_symbols(void);
+H5TEST_DLL int shutdown_symbols(void);
+H5TEST_DLL int print_metadata_retries_info(hid_t fid);
 
 #ifdef __cplusplus
 }
diff --git a/test/swmr_generator.c b/test/swmr_generator.c
index 93cfa0f..51caa27 100644
--- a/test/swmr_generator.c
+++ b/test/swmr_generator.c
@@ -188,7 +188,7 @@ gen_skeleton(const char *filename, hbool_t verbose, hbool_t swmr_write, int comp
             hbool_t move_dataspace_message =
                 FALSE; /* Whether to move the dataspace message out of object header chunk #0 */
 
-            generate_name(name_buf, u, v);
+            generate_name(name_buf, sizeof(name_buf), u, v);
             if ((dsid = H5Dcreate2(fid, name_buf, tid, sid, H5P_DEFAULT, dcpl, H5P_DEFAULT)) < 0)
                 return -1;
 
diff --git a/test/tattr.c b/test/tattr.c
index 2859f4c..d214719 100644
--- a/test/tattr.c
+++ b/test/tattr.c
@@ -2737,7 +2737,7 @@ test_attr_dense_rename(hid_t fcpl, hid_t fapl)
             CHECK(ret, FAIL, "H5Aclose");
 
             /* Rename attribute */
-            HDsprintf(new_attrname, "new attr %02u", u);
+            HDsnprintf(new_attrname, sizeof(new_attrname), "new attr %02u", u);
 
             /* Rename attribute */
             ret = H5Arename_by_name(fid, DSET1_NAME, attrname, new_attrname, H5P_DEFAULT);
@@ -9015,7 +9015,7 @@ test_attr_shared_rename(hid_t fcpl, hid_t fapl)
                 VERIFY(is_dense, TRUE, "H5O__is_attr_dense_test");
 
             /* Create new attribute name */
-            HDsprintf(attrname2, "new attr %02u", u);
+            HDsnprintf(attrname2, sizeof(attrname2), "new attr %02u", u);
 
             /* Change second dataset's attribute's name */
             ret = H5Arename_by_name(fid, DSET2_NAME, attrname, attrname2, H5P_DEFAULT);
@@ -10126,7 +10126,7 @@ test_attr_bug2(hid_t fcpl, hid_t fapl)
 
     /* Create attributes on group */
     for (i = 0; i < BUG2_NATTR; i++) {
-        HDsprintf(aname, "%03u", i);
+        HDsnprintf(aname, sizeof(aname), "%03u", i);
         aid = H5Acreate2(gid, aname, H5T_STD_I32LE, sid, H5P_DEFAULT, H5P_DEFAULT);
         CHECK(aid, FAIL, "H5Acreate2");
 
@@ -10136,7 +10136,7 @@ test_attr_bug2(hid_t fcpl, hid_t fapl)
 
     /* Delete every other attribute */
     for (i = 1; i < BUG2_NATTR; i += 2) {
-        HDsprintf(aname, "%03u", i);
+        HDsnprintf(aname, sizeof(aname), "%03u", i);
         ret = H5Adelete(gid, aname);
         CHECK(ret, FAIL, "H5Adelete");
     }
@@ -10160,7 +10160,7 @@ test_attr_bug2(hid_t fcpl, hid_t fapl)
 
     /* Open an attribute in the middle */
     i = (BUG2_NATTR / 4) * 2;
-    HDsprintf(aname, "%03u", i);
+    HDsnprintf(aname, sizeof(aname), "%03u", i);
     aid = H5Aopen(gid, aname, H5P_DEFAULT);
     CHECK(aid, FAIL, "H5Aopen");
 
@@ -10203,7 +10203,7 @@ test_attr_bug2(hid_t fcpl, hid_t fapl)
 
     /* Create attributes on group */
     for (i = 0; i < BUG2_NATTR2; i++) {
-        HDsprintf(aname, "%03u", i);
+        HDsnprintf(aname, sizeof(aname), "%03u", i);
         aid = H5Acreate2(gid, aname, H5T_STD_I32LE, sid, H5P_DEFAULT, H5P_DEFAULT);
         CHECK(aid, FAIL, "H5Acreate2");
 
@@ -10213,7 +10213,7 @@ test_attr_bug2(hid_t fcpl, hid_t fapl)
 
     /* Delete every other attribute */
     for (i = 0; i < BUG2_NATTR2; i++) {
-        HDsprintf(aname, "%03u", i);
+        HDsnprintf(aname, sizeof(aname), "%03u", i);
         ret = H5Adelete(gid, aname);
         CHECK(ret, FAIL, "H5Adelete");
     }
diff --git a/test/testmeta.c b/test/testmeta.c
index a3b5160..a62977b 100644
--- a/test/testmeta.c
+++ b/test/testmeta.c
@@ -83,7 +83,7 @@ main(void)
 
     for (i = 0; i < NEXTARRAYS; i++) {
         /* Create dataset */
-        HDsprintf(name, "/ExtArray%06d", i);
+        HDsnprintf(name, sizeof(name), "/ExtArray%06d", i);
         dataset_id =
             H5Dcreate2(file_id, name, H5T_NATIVE_FLOAT, dataspace_id, H5P_DEFAULT, prop_id, H5P_DEFAULT);
 
@@ -108,7 +108,7 @@ main(void)
         floatval = (float)j;
 
         /* Create group to hold data arrays for this object */
-        HDsprintf(name, "/DataArray/%06d", j);
+        HDsnprintf(name, sizeof(name), "/DataArray/%06d", j);
         group_id = H5Gcreate2(file_id, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         if (group_id < 0) {
             HDfprintf(stderr, "Failed to create DataArray group.\n");
@@ -124,7 +124,7 @@ main(void)
             dataspace_id = H5Screate_simple(1, dims, maxdims);
 
             /* Create dataset */
-            HDsprintf(name, "DataArray%06d", i);
+            HDsnprintf(name, sizeof(name), "DataArray%06d", i);
             dataset_id = H5Dcreate2(group_id, name, H5T_NATIVE_FLOAT, dataspace_id, H5P_DEFAULT, H5P_DEFAULT,
                                     H5P_DEFAULT);
             if (dataset_id < 0) {
@@ -170,7 +170,7 @@ main(void)
         /* Extend attribute arrays */
         for (i = 0; i < NEXTARRAYS; i++) {
             /* Open extendable dataset */
-            HDsprintf(name, "/ExtArray%06d", i);
+            HDsnprintf(name, sizeof(name), "/ExtArray%06d", i);
             dataset_id = H5Dopen2(file_id, name, H5P_DEFAULT);
             if (dataset_id < 0) {
                 HDfprintf(stderr, "Failed to open ExtArray dataset.\n");
diff --git a/test/tfile.c b/test/tfile.c
index 717eb91..caf9c62 100644
--- a/test/tfile.c
+++ b/test/tfile.c
@@ -1111,14 +1111,14 @@ test_get_obj_ids(void)
 
     /* creates NGROUPS groups under the root group */
     for (m = 0; m < NGROUPS; m++) {
-        HDsprintf(gname, "group%d", m);
+        HDsnprintf(gname, sizeof(gname), "group%d", m);
         gid[m] = H5Gcreate2(fid, gname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         CHECK(gid[m], FAIL, "H5Gcreate2");
     }
 
     /* create NDSETS datasets under the root group */
     for (n = 0; n < NDSETS; n++) {
-        HDsprintf(dname, "dataset%d", n);
+        HDsnprintf(dname, sizeof(dname), "dataset%d", n);
         dset[n] = H5Dcreate2(fid, dname, H5T_NATIVE_INT, filespace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         CHECK(dset[n], FAIL, "H5Dcreate2");
     }
@@ -1178,7 +1178,7 @@ test_get_obj_ids(void)
 
     /* Open NDSETS datasets under the root group */
     for (n = 0; n < NDSETS; n++) {
-        HDsprintf(dname, "dataset%d", n);
+        HDsnprintf(dname, sizeof(dname), "dataset%d", n);
         dset[n] = H5Dopen2(fid, dname, H5P_DEFAULT);
         CHECK(dset[n], FAIL, "H5Dcreate2");
     }
@@ -4473,7 +4473,7 @@ test_file_freespace(const char *env_h5_drvr)
 
             /* Create datasets in file */
             for (u = 0; u < 10; u++) {
-                HDsprintf(name, "Dataset %u", u);
+                HDsnprintf(name, sizeof(name), "Dataset %u", u);
                 dset = H5Dcreate2(file, name, H5T_STD_U32LE, dspace, H5P_DEFAULT, dcpl, H5P_DEFAULT);
                 CHECK(dset, FAIL, "H5Dcreate2");
 
@@ -4496,7 +4496,7 @@ test_file_freespace(const char *env_h5_drvr)
 
             /* Delete datasets in file */
             for (k = 9; k >= 0; k--) {
-                HDsprintf(name, "Dataset %u", (unsigned)k);
+                HDsnprintf(name, sizeof(name), "Dataset %u", (unsigned)k);
                 ret = H5Ldelete(file, name, H5P_DEFAULT);
                 CHECK(ret, FAIL, "H5Ldelete");
             } /* end for */
@@ -4624,7 +4624,7 @@ test_sects_freespace(const char *env_h5_drvr, hbool_t new_format)
 
         /* Create datasets in file */
         for (u = 0; u < 10; u++) {
-            HDsprintf(name, "Dataset %u", u);
+            HDsnprintf(name, sizeof(name), "Dataset %u", u);
             dset = H5Dcreate2(file, name, H5T_STD_U32LE, dspace, H5P_DEFAULT, dcpl, H5P_DEFAULT);
             CHECK(dset, FAIL, "H5Dcreate2");
 
@@ -4642,7 +4642,7 @@ test_sects_freespace(const char *env_h5_drvr, hbool_t new_format)
 
         /* Delete odd-numbered datasets in file */
         for (u = 0; u < 10; u++) {
-            HDsprintf(name, "Dataset %u", u);
+            HDsnprintf(name, sizeof(name), "Dataset %u", u);
             if (u % 2) {
                 ret = H5Ldelete(file, name, H5P_DEFAULT);
                 CHECK(ret, FAIL, "H5Ldelete");
@@ -7590,7 +7590,7 @@ test_incr_filesize(void)
 
         /* Create datasets in file */
         for (u = 0; u < 10; u++) {
-            HDsprintf(name, "Dataset %u", u);
+            HDsnprintf(name, sizeof(name), "Dataset %u", u);
             dset = H5Dcreate2(fid, name, H5T_STD_U32LE, dspace, H5P_DEFAULT, dcpl, H5P_DEFAULT);
             CHECK(dset, FAIL, "H5Dcreate2");
 
diff --git a/test/th5o.c b/test/th5o.c
index 9504f7a..4ffcbef 100644
--- a/test/th5o.c
+++ b/test/th5o.c
@@ -1738,7 +1738,7 @@ test_h5o_getinfo_visit(void)
     /* Attach 10 attributes to "group1" */
     for (j = 0; j < 10; j++) {
         /* Create the attribute name */
-        HDsprintf(attrname, "attr%u", j);
+        HDsnprintf(attrname, sizeof(attrname), "attr%u", j);
         /* Create the attribute */
         aid = H5Acreate2(gid1, attrname, H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT);
         CHECK(aid, FAIL, "H5Acreate2");
diff --git a/test/titerate.c b/test/titerate.c
index 1d87343..5796f11 100644
--- a/test/titerate.c
+++ b/test/titerate.c
@@ -156,7 +156,7 @@ test_iter_group(hid_t fapl, hbool_t new_format)
     CHECK(filespace, FAIL, "H5Screate");
 
     for (i = 0; i < NDATASETS; i++) {
-        HDsprintf(name, "Dataset %d", i);
+        HDsnprintf(name, sizeof(name), "Dataset %d", i);
         dataset = H5Dcreate2(file, name, datatype, filespace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         CHECK(dataset, FAIL, "H5Dcreate2");
 
@@ -436,7 +436,7 @@ test_iter_attr(hid_t fapl, hbool_t new_format)
     CHECK(dataset, FAIL, "H5Dcreate2");
 
     for (i = 0; i < NATTR; i++) {
-        HDsprintf(name, "Attribute %02d", i);
+        HDsnprintf(name, sizeof(name), "Attribute %02d", i);
         attribute = H5Acreate2(dataset, name, H5T_NATIVE_INT, filespace, H5P_DEFAULT, H5P_DEFAULT);
         CHECK(attribute, FAIL, "H5Acreate2");
 
@@ -649,7 +649,7 @@ test_iter_group_large(hid_t fapl)
 
     /* Create a bunch of groups */
     for (i = 0; i < ITER_NGROUPS; i++) {
-        HDsprintf(gname, "Group_%d", i);
+        HDsnprintf(gname, sizeof(gname), "Group_%d", i);
 
         /* Add the name to the list of objects in the root group */
         HDstrcpy(names[i].name, gname);
@@ -766,7 +766,7 @@ test_grp_memb_funcs(hid_t fapl)
     CHECK(filespace, FAIL, "H5Screate");
 
     for (i = 0; i < NDATASETS; i++) {
-        HDsprintf(name, "Dataset %d", i);
+        HDsnprintf(name, sizeof(name), "Dataset %d", i);
         dataset = H5Dcreate2(file, name, datatype, filespace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         CHECK(dataset, FAIL, "H5Dcreate2");
 
diff --git a/test/unlink.c b/test/unlink.c
index 2527e94..265c497 100644
--- a/test/unlink.c
+++ b/test/unlink.c
@@ -179,12 +179,12 @@ test_many(hid_t file)
     /* Create a bunch of names and unlink them in order */
     TESTING("forward unlink");
     for (i = 0; i < how_many; i++) {
-        HDsprintf(name, "obj_%05d", i);
+        HDsnprintf(name, sizeof(name), "obj_%05d", i);
         if (H5Lcreate_hard(work, "/test_many_foo", H5L_SAME_LOC, name, H5P_DEFAULT, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
     for (i = 0; i < how_many; i++) {
-        HDsprintf(name, "obj_%05d", i);
+        HDsnprintf(name, sizeof(name), "obj_%05d", i);
         if (H5Ldelete(work, name, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -193,12 +193,12 @@ test_many(hid_t file)
     /* Create a bunch of names and unlink them in reverse order */
     TESTING("backward unlink");
     for (i = 0; i < how_many; i++) {
-        HDsprintf(name, "obj_%05d", i);
+        HDsnprintf(name, sizeof(name), "obj_%05d", i);
         if (H5Lcreate_hard(work, "/test_many_foo", H5L_SAME_LOC, name, H5P_DEFAULT, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
     for (i = (how_many - 1); i >= 0; --i) {
-        HDsprintf(name, "obj_%05d", i);
+        HDsnprintf(name, sizeof(name), "obj_%05d", i);
         if (H5Ldelete(work, name, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -207,15 +207,15 @@ test_many(hid_t file)
     /* Create a bunch of names and unlink them from both directions */
     TESTING("inward unlink");
     for (i = 0; i < how_many; i++) {
-        HDsprintf(name, "obj_%05d", i);
+        HDsnprintf(name, sizeof(name), "obj_%05d", i);
         if (H5Lcreate_hard(work, "/test_many_foo", H5L_SAME_LOC, name, H5P_DEFAULT, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
     for (i = 0; i < how_many; i++) {
         if (i % 2)
-            HDsprintf(name, "obj_%05d", how_many - (1 + i / 2));
+            HDsnprintf(name, sizeof(name), "obj_%05d", how_many - (1 + i / 2));
         else
-            HDsprintf(name, "obj_%05d", i / 2);
+            HDsnprintf(name, sizeof(name), "obj_%05d", i / 2);
         if (H5Ldelete(work, name, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -224,15 +224,15 @@ test_many(hid_t file)
     /* Create a bunch of names and unlink them from the midle */
     TESTING("outward unlink");
     for (i = 0; i < how_many; i++) {
-        HDsprintf(name, "obj_%05d", i);
+        HDsnprintf(name, sizeof(name), "obj_%05d", i);
         if (H5Lcreate_hard(work, "/test_many_foo", H5L_SAME_LOC, name, H5P_DEFAULT, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
     for (i = (how_many - 1); i >= 0; --i) {
         if (i % 2)
-            HDsprintf(name, "obj_%05d", how_many - (1 + i / 2));
+            HDsnprintf(name, sizeof(name), "obj_%05d", how_many - (1 + i / 2));
         else
-            HDsprintf(name, "obj_%05d", i / 2);
+            HDsnprintf(name, sizeof(name), "obj_%05d", i / 2);
         if (H5Ldelete(work, name, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -938,7 +938,7 @@ test_filespace(hid_t fapl)
     /* Alternate adding attributes to each one */
     for (u = 0; u < FILESPACE_NATTR; u++) {
         /* Set the name of the attribute to create */
-        HDsprintf(objname, "%s %u", ATTRNAME, u);
+        HDsnprintf(objname, sizeof(objname), "%s %u", ATTRNAME, u);
 
         /* Create an attribute on the first dataset */
         if ((attr = H5Acreate2(dataset, objname, H5T_NATIVE_INT, attr_space, H5P_DEFAULT, H5P_DEFAULT)) < 0)
@@ -1070,7 +1070,7 @@ test_filespace(hid_t fapl)
 
     /* Create a many groups to remove */
     for (u = 0; u < UNLINK_NGROUPS; u++) {
-        HDsprintf(objname, "%s %u", GROUPNAME, u);
+        HDsnprintf(objname, sizeof(objname), "%s %u", GROUPNAME, u);
         if ((group = H5Gcreate2(file, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
         if (H5Gclose(group) < 0)
@@ -1080,7 +1080,7 @@ test_filespace(hid_t fapl)
     /* Remove the all the groups */
     /* (Remove them in reverse order just to make file size calculation easier -QAK) */
     for (u = UNLINK_NGROUPS; u > 0; u--) {
-        HDsprintf(objname, "%s %u", GROUPNAME, (u - 1));
+        HDsnprintf(objname, sizeof(objname), "%s %u", GROUPNAME, (u - 1));
         if (H5Ldelete(file, objname, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -1148,21 +1148,21 @@ test_filespace(hid_t fapl)
     /* Create a complex group hierarchy to remove */
     for (u = 0; u < FILESPACE_TOP_GROUPS; u++) {
         /* Create group */
-        HDsprintf(objname, "%s %u", GROUPNAME, u);
+        HDsnprintf(objname, sizeof(objname), "%s %u", GROUPNAME, u);
         if ((group = H5Gcreate2(file, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
 
         /* Create nested groups inside top groups */
         for (v = 0; v < FILESPACE_NESTED_GROUPS; v++) {
             /* Create group */
-            HDsprintf(objname, "%s %u", GROUP2NAME, v);
+            HDsnprintf(objname, sizeof(objname), "%s %u", GROUP2NAME, v);
             if ((group2 = H5Gcreate2(group, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
                 FAIL_STACK_ERROR;
 
             /* Create datasets inside nested groups */
             for (w = 0; w < FILESPACE_NDATASETS; w++) {
                 /* Create & close a dataset */
-                HDsprintf(objname, "%s %u", DATASETNAME, w);
+                HDsnprintf(objname, sizeof(objname), "%s %u", DATASETNAME, w);
                 if ((dataset = H5Dcreate2(group2, objname, H5T_NATIVE_INT, space, H5P_DEFAULT, H5P_DEFAULT,
                                           H5P_DEFAULT)) < 0)
                     FAIL_STACK_ERROR;
@@ -1184,21 +1184,21 @@ test_filespace(hid_t fapl)
     /* (Remove them in reverse order just to make file size calculation easier -QAK) */
     for (u = FILESPACE_TOP_GROUPS; u > 0; u--) {
         /* Open group */
-        HDsprintf(objname, "%s %u", GROUPNAME, (u - 1));
+        HDsnprintf(objname, sizeof(objname), "%s %u", GROUPNAME, (u - 1));
         if ((group = H5Gopen2(file, objname, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
 
         /* Open nested groups inside top groups */
         for (v = 0; v < FILESPACE_NESTED_GROUPS; v++) {
             /* Create group */
-            HDsprintf(objname, "%s %u", GROUP2NAME, v);
+            HDsnprintf(objname, sizeof(objname), "%s %u", GROUP2NAME, v);
             if ((group2 = H5Gopen2(group, objname, H5P_DEFAULT)) < 0)
                 FAIL_STACK_ERROR;
 
             /* Remove datasets inside nested groups */
             for (w = 0; w < FILESPACE_NDATASETS; w++) {
                 /* Remove dataset */
-                HDsprintf(objname, "%s %u", DATASETNAME, w);
+                HDsnprintf(objname, sizeof(objname), "%s %u", DATASETNAME, w);
                 if (H5Ldelete(group2, objname, H5P_DEFAULT) < 0)
                     FAIL_STACK_ERROR;
             } /* end for */
@@ -1208,7 +1208,7 @@ test_filespace(hid_t fapl)
                 FAIL_STACK_ERROR;
 
             /* Remove nested group */
-            HDsprintf(objname, "%s %u", GROUP2NAME, v);
+            HDsnprintf(objname, sizeof(objname), "%s %u", GROUP2NAME, v);
             if (H5Ldelete(group, objname, H5P_DEFAULT) < 0)
                 FAIL_STACK_ERROR;
         } /* end for */
@@ -1218,7 +1218,7 @@ test_filespace(hid_t fapl)
             FAIL_STACK_ERROR;
 
         /* Remove top group */
-        HDsprintf(objname, "%s %u", GROUPNAME, (u - 1));
+        HDsnprintf(objname, sizeof(objname), "%s %u", GROUPNAME, (u - 1));
         if (H5Ldelete(file, objname, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -1502,7 +1502,7 @@ test_create_unlink(const char *msg, hid_t fapl)
 
     /* Create a many groups to remove */
     for (u = 0; u < UNLINK_NGROUPS; u++) {
-        HDsprintf(groupname, "%s %u", GROUPNAME, u);
+        HDsnprintf(groupname, sizeof(groupname), "%s %u", GROUPNAME, u);
         if ((group = H5Gcreate2(file, groupname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0) {
             H5_FAILED();
             HDprintf("group %s creation failed\n", groupname);
@@ -1517,7 +1517,7 @@ test_create_unlink(const char *msg, hid_t fapl)
 
     /* Remove the all the groups */
     for (u = 0; u < UNLINK_NGROUPS; u++) {
-        HDsprintf(groupname, "%s %u", GROUPNAME, u);
+        HDsnprintf(groupname, sizeof(groupname), "%s %u", GROUPNAME, u);
         if (H5Ldelete(file, groupname, H5P_DEFAULT) < 0) {
             H5_FAILED();
             HDprintf("Unlinking group %s failed\n", groupname);
@@ -1765,7 +1765,7 @@ test_unlink_rightleaf(hid_t fid)
 
     /* Create all the groups */
     for (n = 0; n < ngroups; n++) {
-        HDsprintf(name, "Zone%d", n + 1);
+        HDsnprintf(name, sizeof(name), "Zone%d", n + 1);
         if ((gids[n] = H5Gcreate2(rootid, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
     } /* end for */
@@ -1774,7 +1774,7 @@ test_unlink_rightleaf(hid_t fid)
     for (n = 0; n < ngroups; n++) {
         if (delete_node(rootid, gids[n]) < 0)
             TEST_ERROR;
-        HDsprintf(name, "Zone%d", n + 1);
+        HDsnprintf(name, sizeof(name), "Zone%d", n + 1);
         if ((gids[n] = H5Gcreate2(rootid, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             TEST_ERROR;
     } /* end for */
@@ -1854,7 +1854,7 @@ test_unlink_rightnode(hid_t fid)
 
     /* Create all the groups */
     for (n = 0; n < ngroups; n++) {
-        HDsprintf(name, "ZoneB%d", n + 1);
+        HDsnprintf(name, sizeof(name), "ZoneB%d", n + 1);
         if ((gids[n] = H5Gcreate2(rootid, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -1946,7 +1946,7 @@ test_unlink_middlenode(hid_t fid)
 
     /* Create all the groups */
     for (n = 0; n < ngroups; n++) {
-        HDsprintf(name, "ZoneC%d", n + 1);
+        HDsnprintf(name, sizeof(name), "ZoneC%d", n + 1);
         if ((gids[n] = H5Gcreate2(rootid, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
@@ -2676,7 +2676,7 @@ test_full_group_compact(hid_t fapl)
 
     /* Create several objects to link to */
     for (u = 0; u < FULL_GROUP_NUM_KEEP; u++) {
-        HDsprintf(objname, "keep %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "keep %u\n", u);
         if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
         if (H5Gclose(gid2) < 0)
@@ -2713,15 +2713,15 @@ test_full_group_compact(hid_t fapl)
 
     /* Create hard links to objects in group to keep */
     for (u = 0; u < FULL_GROUP_NUM_KEEP; u++) {
-        HDsprintf(objname, "/keep/keep %u\n", u);
-        HDsprintf(objname2, "keep %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "/keep/keep %u\n", u);
+        HDsnprintf(objname2, sizeof(objname2), "keep %u\n", u);
         if (H5Lcreate_hard(file_id, objname, gid, objname2, H5P_DEFAULT, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
 
     /* Create several objects to delete */
     for (u = 0; u < FULL_GROUP_NUM_DELETE_COMPACT; u++) {
-        HDsprintf(objname, "delete %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "delete %u\n", u);
         if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
         if (H5Gclose(gid2) < 0)
@@ -2742,7 +2742,7 @@ test_full_group_compact(hid_t fapl)
 
     /* Check reference count on objects to keep */
     for (u = 0; u < FULL_GROUP_NUM_KEEP; u++) {
-        HDsprintf(objname, "/keep/keep %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "/keep/keep %u\n", u);
         if (H5Oget_info_by_name3(file_id, objname, &oi, H5O_INFO_BASIC, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
         if (oi.rc != 2)
@@ -2763,7 +2763,7 @@ test_full_group_compact(hid_t fapl)
 
     /* Check reference count on objects to keep */
     for (u = 0; u < FULL_GROUP_NUM_KEEP; u++) {
-        HDsprintf(objname, "/keep/keep %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "/keep/keep %u\n", u);
         if (H5Oget_info_by_name3(file_id, objname, &oi, H5O_INFO_BASIC, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
         if (oi.rc != 1)
@@ -2838,7 +2838,7 @@ test_full_group_dense(hid_t fapl)
 
     /* Create several objects to link to */
     for (u = 0; u < FULL_GROUP_NUM_KEEP; u++) {
-        HDsprintf(objname, "keep %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "keep %u\n", u);
         if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
         if (H5Gclose(gid2) < 0)
@@ -2890,15 +2890,15 @@ test_full_group_dense(hid_t fapl)
 
     /* Create hard links to objects in group to keep */
     for (u = 0; u < FULL_GROUP_NUM_KEEP; u++) {
-        HDsprintf(objname, "/keep/keep %u\n", u);
-        HDsprintf(objname2, "keep %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "/keep/keep %u\n", u);
+        HDsnprintf(objname2, sizeof(objname2), "keep %u\n", u);
         if (H5Lcreate_hard(file_id, objname, gid, objname2, H5P_DEFAULT, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
     } /* end for */
 
     /* Create several objects to delete */
     for (u = 0; u < FULL_GROUP_NUM_DELETE_DENSE; u++) {
-        HDsprintf(objname, "delete %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "delete %u\n", u);
         if ((gid2 = H5Gcreate2(gid, objname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             FAIL_STACK_ERROR;
         if (H5Gclose(gid2) < 0)
@@ -2919,7 +2919,7 @@ test_full_group_dense(hid_t fapl)
 
     /* Check reference count on objects to keep */
     for (u = 0; u < FULL_GROUP_NUM_KEEP; u++) {
-        HDsprintf(objname, "/keep/keep %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "/keep/keep %u\n", u);
         if (H5Oget_info_by_name3(file_id, objname, &oi, H5O_INFO_BASIC, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
         if (oi.rc != 2)
@@ -2940,7 +2940,7 @@ test_full_group_dense(hid_t fapl)
 
     /* Check reference count on objects to keep */
     for (u = 0; u < FULL_GROUP_NUM_KEEP; u++) {
-        HDsprintf(objname, "/keep/keep %u\n", u);
+        HDsnprintf(objname, sizeof(objname), "/keep/keep %u\n", u);
         if (H5Oget_info_by_name3(file_id, objname, &oi, H5O_INFO_BASIC, H5P_DEFAULT) < 0)
             FAIL_STACK_ERROR;
         if (oi.rc != 1)
diff --git a/test/vfd.c b/test/vfd.c
index d6f6d61..b4fc742 100644
--- a/test/vfd.c
+++ b/test/vfd.c
@@ -1538,19 +1538,19 @@ test_multi(void)
     memb_map[H5FD_MEM_BTREE] = H5FD_MEM_BTREE;
     memb_map[H5FD_MEM_GHEAP] = H5FD_MEM_GHEAP;
 
-    HDsprintf(sv[H5FD_MEM_SUPER], "%%s-%c.h5", 's');
+    HDsnprintf(sv[H5FD_MEM_SUPER], 32, "%%s-%c.h5", 's');
     memb_name[H5FD_MEM_SUPER] = sv[H5FD_MEM_SUPER];
     memb_addr[H5FD_MEM_SUPER] = 0;
 
-    HDsprintf(sv[H5FD_MEM_BTREE], "%%s-%c.h5", 'b');
+    HDsnprintf(sv[H5FD_MEM_BTREE], 32, "%%s-%c.h5", 'b');
     memb_name[H5FD_MEM_BTREE] = sv[H5FD_MEM_BTREE];
     memb_addr[H5FD_MEM_BTREE] = HADDR_MAX / 4;
 
-    HDsprintf(sv[H5FD_MEM_DRAW], "%%s-%c.h5", 'r');
+    HDsnprintf(sv[H5FD_MEM_DRAW], 32, "%%s-%c.h5", 'r');
     memb_name[H5FD_MEM_DRAW] = sv[H5FD_MEM_DRAW];
     memb_addr[H5FD_MEM_DRAW] = HADDR_MAX / 2;
 
-    HDsprintf(sv[H5FD_MEM_GHEAP], "%%s-%c.h5", 'g');
+    HDsnprintf(sv[H5FD_MEM_GHEAP], 32, "%%s-%c.h5", 'g');
     memb_name[H5FD_MEM_GHEAP] = sv[H5FD_MEM_GHEAP];
     memb_addr[H5FD_MEM_GHEAP] = (HADDR_MAX / 4) * 3;
 
@@ -1787,12 +1787,12 @@ test_multi_compat(void)
     memb_map[H5FD_MEM_DRAW] = H5FD_MEM_DRAW;
 
     memb_fapl[H5FD_MEM_SUPER] = H5P_DEFAULT;
-    HDsprintf(sv[H5FD_MEM_SUPER], "%%s-%c.h5", 's');
+    HDsnprintf(sv[H5FD_MEM_SUPER], 32, "%%s-%c.h5", 's');
     memb_name[H5FD_MEM_SUPER] = sv[H5FD_MEM_SUPER];
     memb_addr[H5FD_MEM_SUPER] = 0;
 
     memb_fapl[H5FD_MEM_DRAW] = H5P_DEFAULT;
-    HDsprintf(sv[H5FD_MEM_DRAW], "%%s-%c.h5", 'r');
+    HDsnprintf(sv[H5FD_MEM_DRAW], 32, "%%s-%c.h5", 'r');
     memb_name[H5FD_MEM_DRAW] = sv[H5FD_MEM_DRAW];
     memb_addr[H5FD_MEM_DRAW] = HADDR_MAX / 2;
 
@@ -1804,12 +1804,12 @@ test_multi_compat(void)
     /* Make copy for the data file in the build directory, to protect the
      * original file in the source directory
      */
-    HDsprintf(filename_s, "%s-%c.h5", MULTI_COMPAT_BASENAME, 's');
-    HDsprintf(newname_s, "%s-%c.h5", FILENAME[9], 's');
+    HDsnprintf(filename_s, sizeof(filename_s), "%s-%c.h5", MULTI_COMPAT_BASENAME, 's');
+    HDsnprintf(newname_s, sizeof(newname_s), "%s-%c.h5", FILENAME[9], 's');
     h5_make_local_copy(filename_s, newname_s);
 
-    HDsprintf(filename_r, "%s-%c.h5", MULTI_COMPAT_BASENAME, 'r');
-    HDsprintf(newname_r, "%s-%c.h5", FILENAME[9], 'r');
+    HDsnprintf(filename_r, sizeof(filename_r), "%s-%c.h5", MULTI_COMPAT_BASENAME, 'r');
+    HDsnprintf(newname_r, sizeof(newname_r), "%s-%c.h5", FILENAME[9], 'r');
     h5_make_local_copy(filename_r, newname_r);
 
     /* Reopen the file for read only.  Verify 1.8 library can open file
diff --git a/testpar/t_2Gio.c b/testpar/t_2Gio.c
index 63d6b69..ad8a15e 100644
--- a/testpar/t_2Gio.c
+++ b/testpar/t_2Gio.c
@@ -3704,9 +3704,10 @@ test_actual_io_mode(int selection_mode)
     /* Test values */
     if (actual_chunk_opt_mode_expected != (H5D_mpio_actual_chunk_opt_mode_t)-1 &&
         actual_io_mode_expected != (H5D_mpio_actual_io_mode_t)-1) {
-        HDsprintf(message, "Actual Chunk Opt Mode has the correct value for %s.\n", test_name);
+        HDsnprintf(message, sizeof(message), "Actual Chunk Opt Mode has the correct value for %s.\n",
+                   test_name);
         VRFY((actual_chunk_opt_mode_write == actual_chunk_opt_mode_expected), message);
-        HDsprintf(message, "Actual IO Mode has the correct value for %s.\n", test_name);
+        HDsnprintf(message, sizeof(message), "Actual IO Mode has the correct value for %s.\n", test_name);
         VRFY((actual_io_mode_write == actual_io_mode_expected), message);
     }
     else {
@@ -4100,10 +4101,12 @@ test_no_collective_cause_mode(int selection_mode)
 
     /* Test values */
     HDmemset(message, 0, sizeof(message));
-    HDsprintf(message, "Local cause of Broken Collective I/O has the correct value for %s.\n", test_name);
+    HDsnprintf(message, sizeof(message),
+               "Local cause of Broken Collective I/O has the correct value for %s.\n", test_name);
     VRFY((no_collective_cause_local_write == no_collective_cause_local_expected), message);
     HDmemset(message, 0, sizeof(message));
-    HDsprintf(message, "Global cause of Broken Collective I/O has the correct value for %s.\n", test_name);
+    HDsnprintf(message, sizeof(message),
+               "Global cause of Broken Collective I/O has the correct value for %s.\n", test_name);
     VRFY((no_collective_cause_global_write == no_collective_cause_global_expected), message);
 
     /* Release some resources */
diff --git a/testpar/t_dset.c b/testpar/t_dset.c
index eb11b32..f34cc1d 100644
--- a/testpar/t_dset.c
+++ b/testpar/t_dset.c
@@ -3262,9 +3262,10 @@ test_actual_io_mode(int selection_mode)
     /* Test values */
     if (actual_chunk_opt_mode_expected != (H5D_mpio_actual_chunk_opt_mode_t)-1 &&
         actual_io_mode_expected != (H5D_mpio_actual_io_mode_t)-1) {
-        HDsprintf(message, "Actual Chunk Opt Mode has the correct value for %s.\n", test_name);
+        HDsnprintf(message, sizeof(message), "Actual Chunk Opt Mode has the correct value for %s.\n",
+                   test_name);
         VRFY((actual_chunk_opt_mode_write == actual_chunk_opt_mode_expected), message);
-        HDsprintf(message, "Actual IO Mode has the correct value for %s.\n", test_name);
+        HDsnprintf(message, sizeof(message), "Actual IO Mode has the correct value for %s.\n", test_name);
         VRFY((actual_io_mode_write == actual_io_mode_expected), message);
     }
     else {
diff --git a/testpar/t_mdset.c b/testpar/t_mdset.c
index 339ca33..54d75e6 100644
--- a/testpar/t_mdset.c
+++ b/testpar/t_mdset.c
@@ -183,7 +183,7 @@ multiple_dset_write(void)
     VRFY((ret >= 0), "set fill-value succeeded");
 
     for (n = 0; n < ndatasets; n++) {
-        HDsprintf(dname, "dataset %d", n);
+        HDsnprintf(dname, sizeof(dname), "dataset %d", n);
         dataset = H5Dcreate2(iof, dname, H5T_NATIVE_DOUBLE, filespace, H5P_DEFAULT, dcpl, H5P_DEFAULT);
         VRFY((dataset > 0), dname);
 
@@ -878,11 +878,11 @@ collective_group_write(void)
     /* creates ngroups groups under the root group, writes chunked
      * datasets in parallel. */
     for (m = 0; m < ngroups; m++) {
-        HDsprintf(gname, "group%d", m);
+        HDsnprintf(gname, sizeof(gname), "group%d", m);
         gid = H5Gcreate2(fid, gname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         VRFY((gid > 0), gname);
 
-        HDsprintf(dname, "dataset%d", m);
+        HDsnprintf(dname, sizeof(dname), "dataset%d", m);
         did = H5Dcreate2(gid, dname, H5T_NATIVE_INT, filespace, H5P_DEFAULT, dcpl, H5P_DEFAULT);
         VRFY((did > 0), dname);
 
@@ -979,12 +979,12 @@ group_dataset_read(hid_t fid, int mpi_rank, int m)
     VRFY((outdata != NULL), "HDmalloc succeeded for outdata");
 
     /* open every group under root group. */
-    HDsprintf(gname, "group%d", m);
+    HDsnprintf(gname, sizeof(gname), "group%d", m);
     gid = H5Gopen2(fid, gname, H5P_DEFAULT);
     VRFY((gid > 0), gname);
 
     /* check the data. */
-    HDsprintf(dname, "dataset%d", m);
+    HDsnprintf(dname, sizeof(dname), "dataset%d", m);
     did = H5Dopen2(gid, dname, H5P_DEFAULT);
     VRFY((did > 0), dname);
 
@@ -1080,7 +1080,7 @@ multiple_group_write(void)
     /* creates ngroups groups under the root group, writes datasets in
      * parallel. */
     for (m = 0; m < ngroups; m++) {
-        HDsprintf(gname, "group%d", m);
+        HDsnprintf(gname, sizeof(gname), "group%d", m);
         gid = H5Gcreate2(fid, gname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         VRFY((gid > 0), gname);
 
@@ -1136,7 +1136,7 @@ write_dataset(hid_t memspace, hid_t filespace, hid_t gid)
     VRFY((outme != NULL), "HDmalloc succeeded for outme");
 
     for (n = 0; n < NDATASET; n++) {
-        HDsprintf(dname, "dataset%d", n);
+        HDsnprintf(dname, sizeof(dname), "dataset%d", n);
         did = H5Dcreate2(gid, dname, H5T_NATIVE_INT, filespace, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         VRFY((did > 0), dname);
 
@@ -1174,7 +1174,7 @@ create_group_recursive(hid_t memspace, hid_t filespace, hid_t gid, int counter)
     }
 #endif /* BARRIER_CHECKS */
 
-    HDsprintf(gname, "%dth_child_group", counter + 1);
+    HDsnprintf(gname, sizeof(gname), "%dth_child_group", counter + 1);
     child_gid = H5Gcreate2(gid, gname, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
     VRFY((child_gid > 0), gname);
 
@@ -1228,7 +1228,7 @@ multiple_group_read(void)
 
     /* open every group under root group. */
     for (m = 0; m < ngroups; m++) {
-        HDsprintf(gname, "group%d", m);
+        HDsnprintf(gname, sizeof(gname), "group%d", m);
         gid = H5Gopen2(fid, gname, H5P_DEFAULT);
         VRFY((gid > 0), gname);
 
@@ -1285,7 +1285,7 @@ read_dataset(hid_t memspace, hid_t filespace, hid_t gid)
     VRFY((outdata != NULL), "HDmalloc succeeded for outdata");
 
     for (n = 0; n < NDATASET; n++) {
-        HDsprintf(dname, "dataset%d", n);
+        HDsnprintf(dname, sizeof(dname), "dataset%d", n);
         did = H5Dopen2(gid, dname, H5P_DEFAULT);
         VRFY((did > 0), dname);
 
@@ -1336,7 +1336,7 @@ recursive_read_group(hid_t memspace, hid_t filespace, hid_t gid, int counter)
         nerrors += err_num;
 
     if (counter < GROUP_DEPTH) {
-        HDsprintf(gname, "%dth_child_group", counter + 1);
+        HDsnprintf(gname, sizeof(gname), "%dth_child_group", counter + 1);
         child_gid = H5Gopen2(gid, gname, H5P_DEFAULT);
         VRFY((child_gid > 0), gname);
         recursive_read_group(memspace, filespace, child_gid, counter + 1);
@@ -1358,7 +1358,7 @@ write_attribute(hid_t obj_id, int this_type, int num)
     MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);
 
     if (this_type == is_group) {
-        HDsprintf(attr_name, "Group Attribute %d", num);
+        HDsnprintf(attr_name, sizeof(attr_name), "Group Attribute %d", num);
         sid = H5Screate(H5S_SCALAR);
         aid = H5Acreate2(obj_id, attr_name, H5T_NATIVE_INT, sid, H5P_DEFAULT, H5P_DEFAULT);
         H5Awrite(aid, H5T_NATIVE_INT, &num);
@@ -1366,7 +1366,7 @@ write_attribute(hid_t obj_id, int this_type, int num)
         H5Sclose(sid);
     } /* end if */
     else if (this_type == is_dset) {
-        HDsprintf(attr_name, "Dataset Attribute %d", num);
+        HDsnprintf(attr_name, sizeof(attr_name), "Dataset Attribute %d", num);
         for (i = 0; i < 8; i++)
             attr_data[i] = i;
         sid = H5Screate_simple(dspace_rank, dspace_dims, NULL);
@@ -1389,14 +1389,14 @@ read_attribute(hid_t obj_id, int this_type, int num)
     MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);
 
     if (this_type == is_group) {
-        HDsprintf(attr_name, "Group Attribute %d", num);
+        HDsnprintf(attr_name, sizeof(attr_name), "Group Attribute %d", num);
         aid = H5Aopen(obj_id, attr_name, H5P_DEFAULT);
         H5Aread(aid, H5T_NATIVE_INT, &in_num);
         vrfy_errors = dataset_vrfy(NULL, NULL, NULL, group_block, &in_num, &num);
         H5Aclose(aid);
     }
     else if (this_type == is_dset) {
-        HDsprintf(attr_name, "Dataset Attribute %d", num);
+        HDsnprintf(attr_name, sizeof(attr_name), "Dataset Attribute %d", num);
         for (i = 0; i < 8; i++)
             out_data[i] = i;
         aid = H5Aopen(obj_id, attr_name, H5P_DEFAULT);
diff --git a/testpar/t_vfd.c b/testpar/t_vfd.c
index 81e4983..ad296ad 100644
--- a/testpar/t_vfd.c
+++ b/testpar/t_vfd.c
@@ -571,17 +571,20 @@ vector_read_test_1(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer_
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector read test 1 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 1 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector read test 1 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 1 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector read test 1 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 1 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -817,17 +820,20 @@ vector_read_test_2(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer_
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector read test 2 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 2 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector read test 2 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 2 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector read test 2 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 2 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -1139,17 +1145,20 @@ vector_read_test_3(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer_
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector read test 3 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 3 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector read test 3 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 3 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector read test 3 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 3 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -1508,17 +1517,20 @@ vector_read_test_4(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer_
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector read test 4 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 4 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector read test 4 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 4 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector read test 4 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 4 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -1951,17 +1963,20 @@ vector_read_test_5(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer_
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector read test 5 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 5 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector read test 5 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 5 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector read test 5 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector read test 5 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -2204,17 +2219,20 @@ vector_write_test_1(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector write test 1 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 1 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector write test 1 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 1 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector write test 1 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 1 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -2403,17 +2421,20 @@ vector_write_test_2(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector write test 2 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 2 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector write test 2 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 2 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector write test 2 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 2 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -2668,17 +2689,20 @@ vector_write_test_3(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector write test 3 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 3 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector write test 3 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 3 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector write test 3 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 3 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -2950,17 +2974,20 @@ vector_write_test_4(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector write test 4 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 4 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector write test 4 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 4 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector write test 4 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 4 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -3269,17 +3296,20 @@ vector_write_test_5(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector write test 5 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 5 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector write test 5 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 5 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector write test 5 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 5 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
@@ -3701,17 +3731,20 @@ vector_write_test_6(int file_name_id, int mpi_rank, int mpi_size, H5FD_mpio_xfer
 
         if (xfer_mode == H5FD_MPIO_INDEPENDENT) {
 
-            sprintf(test_title, "parallel vector write test 6 -- %s / independent", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 6 -- %s / independent",
+                     vfd_name);
         }
         else if (coll_opt_mode == H5FD_MPIO_INDIVIDUAL_IO) {
 
-            sprintf(test_title, "parallel vector write test 6 -- %s / col op / ind I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 6 -- %s / col op / ind I/O",
+                     vfd_name);
         }
         else {
 
             HDassert(coll_opt_mode == H5FD_MPIO_COLLECTIVE_IO);
 
-            sprintf(test_title, "parallel vector write test 6 -- %s / col op / col I/O", vfd_name);
+            snprintf(test_title, sizeof(test_title), "parallel vector write test 6 -- %s / col op / col I/O",
+                     vfd_name);
         }
 
         TESTING(test_title);
diff --git a/tools/src/h5perf/sio_engine.c b/tools/src/h5perf/sio_engine.c
index c12e1da..e113e82 100644
--- a/tools/src/h5perf/sio_engine.c
+++ b/tools/src/h5perf/sio_engine.c
@@ -522,7 +522,7 @@ do_write(results *res, file_descr *fd, parameters *parms, void *buffer)
                 } /* end if */
             }     /* end if */
 
-            HDsprintf(dname, "Dataset_%ld", (unsigned long)parms->num_bytes);
+            HDsnprintf(dname, sizeof(dname), "Dataset_%ld", (unsigned long)parms->num_bytes);
             h5ds_id =
                 H5Dcreate2(fd->h5fd, dname, ELMT_H5_TYPE, h5dset_space_id, H5P_DEFAULT, h5dcpl, H5P_DEFAULT);
 
@@ -851,7 +851,7 @@ do_read(results *res, file_descr *fd, parameters *parms, void *buffer)
             break;
 
         case HDF5:
-            HDsprintf(dname, "Dataset_%ld", (long)parms->num_bytes);
+            HDsnprintf(dname, sizeof(dname), "Dataset_%ld", (long)parms->num_bytes);
             h5ds_id = H5Dopen2(fd->h5fd, dname, H5P_DEFAULT);
             if (h5ds_id < 0) {
                 HDfprintf(stderr, "HDF5 Dataset open failed\n");
@@ -1181,7 +1181,7 @@ set_vfd(parameters *param)
             return -1;
         for (mt = H5FD_MEM_DEFAULT; mt < H5FD_MEM_NTYPES; mt++) {
             memb_fapl[mt] = H5P_DEFAULT;
-            HDsprintf(sv->arr[mt], "%%s-%c.h5", multi_letters[mt]);
+            HDsnprintf(sv->arr[mt], 1024, "%%s-%c.h5", multi_letters[mt]);
             memb_name[mt] = sv->arr[mt];
             memb_addr[mt] = (haddr_t)MAX(mt - 1, 0) * (HADDR_MAX / 10);
         }
diff --git a/tools/src/h5repack/h5repack_copy.c b/tools/src/h5repack/h5repack_copy.c
index c38a431..25df5c7 100644
--- a/tools/src/h5repack/h5repack_copy.c
+++ b/tools/src/h5repack/h5repack_copy.c
@@ -1531,7 +1531,7 @@ print_dataset_info(hid_t dcpl_id, char *objname, double ratio, int pr, pack_opt_
                 {
                     unsigned level = cd_values[0];
 
-                    HDsprintf(temp, "(%d)", level);
+                    HDsnprintf(temp, sizeof(temp), "(%d)", level);
                     HDstrcat(strfilter, temp);
                 }
 #endif
@@ -1545,7 +1545,7 @@ print_dataset_info(hid_t dcpl_id, char *objname, double ratio, int pr, pack_opt_
                     unsigned options_mask = cd_values[0]; /* from dcpl, not filt*/
                     unsigned ppb          = cd_values[1];
 
-                    HDsprintf(temp, "(%d,", ppb);
+                    HDsnprintf(temp, sizeof(temp), "(%d,", ppb);
                     HDstrcat(strfilter, temp);
                     if (options_mask & H5_SZIP_EC_OPTION_MASK)
                         HDstrcpy(temp, "EC) ");
@@ -1588,7 +1588,7 @@ print_dataset_info(hid_t dcpl_id, char *objname, double ratio, int pr, pack_opt_
 
         HDstrcpy(str, "dset     ");
         HDstrcat(str, strfilter);
-        HDsprintf(temp, "  (%.3f:1)", ratio);
+        HDsnprintf(temp, sizeof(temp), "  (%.3f:1)", ratio);
         HDstrcat(str, temp);
         if (options->verbose == 2)
             HDprintf(FORMAT_OBJ_TIME, str, read_time, write_time, objname);
diff --git a/tools/src/misc/h5repart.c b/tools/src/misc/h5repart.c
index f4cef6a..078883d 100644
--- a/tools/src/misc/h5repart.c
+++ b/tools/src/misc/h5repart.c
@@ -242,7 +242,7 @@ main(int argc, char *argv[])
     if (argno >= argc)
         usage(prog_name);
     src_gen_name = argv[argno++];
-    HDsprintf(src_name, src_gen_name, src_membno);
+    HDsnprintf(src_name, NAMELEN, src_gen_name, src_membno);
     src_is_family = strcmp(src_name, src_gen_name);
 
     if ((src = HDopen(src_name, O_RDONLY)) < 0) {
@@ -264,7 +264,7 @@ main(int argc, char *argv[])
     if (argno >= argc)
         usage(prog_name);
     dst_gen_name = argv[argno++];
-    HDsprintf(dst_name, dst_gen_name, dst_membno);
+    HDsnprintf(dst_name, NAMELEN, dst_gen_name, dst_membno);
     dst_is_family = HDstrcmp(dst_name, dst_gen_name);
 
     if ((dst = HDopen(dst_name, O_RDWR | O_CREAT | O_TRUNC, H5_POSIX_CREATE_MODE_RW)) < 0) {
@@ -356,7 +356,7 @@ main(int argc, char *argv[])
                 dst_offset = dst_offset + (off_t)n;
                 break;
             }
-            HDsprintf(src_name, src_gen_name, ++src_membno);
+            HDsnprintf(src_name, NAMELEN, src_gen_name, ++src_membno);
             if ((src = HDopen(src_name, O_RDONLY)) < 0 && ENOENT == errno) {
                 dst_offset = dst_offset + (off_t)n;
                 break;
@@ -404,7 +404,7 @@ main(int argc, char *argv[])
                 }
             }
             HDclose(dst);
-            HDsprintf(dst_name, dst_gen_name, ++dst_membno);
+            HDsnprintf(dst_name, NAMELEN, dst_gen_name, ++dst_membno);
             if ((dst = HDopen(dst_name, O_RDWR | O_CREAT | O_TRUNC, H5_POSIX_CREATE_MODE_RW)) < 0) {
                 HDperror(dst_name);
                 HDexit(EXIT_FAILURE);
diff --git a/tools/test/h5dump/h5dumpgentest.c b/tools/test/h5dump/h5dumpgentest.c
index 339b563..949aa43 100644
--- a/tools/test/h5dump/h5dumpgentest.c
+++ b/tools/test/h5dump/h5dumpgentest.c
@@ -582,7 +582,7 @@ gent_attribute(void)
     dims[0] = 24;
     space   = H5Screate_simple(1, dims, NULL);
     attr    = H5Acreate2(root, "/attr1", H5T_STD_I8BE, space, H5P_DEFAULT, H5P_DEFAULT);
-    HDsprintf(buf, "attribute of root group");
+    HDsnprintf(buf, sizeof(buf), "attribute of root group");
     H5Awrite(attr, H5T_NATIVE_SCHAR, buf);
     H5Sclose(space);
     H5Aclose(attr);
@@ -1382,7 +1382,7 @@ gent_all(void)
     dims[0] = 10;
     space   = H5Screate_simple(1, dims, NULL);
     attr    = H5Acreate2(group, "attr1", H5T_STD_I8BE, space, H5P_DEFAULT, H5P_DEFAULT);
-    HDsprintf(buf, "abcdefghi");
+    HDsnprintf(buf, sizeof(buf), "abcdefghi");
     H5Awrite(attr, H5T_NATIVE_SCHAR, buf);
     H5Sclose(space);
     H5Aclose(attr);
@@ -1418,7 +1418,7 @@ gent_all(void)
     dims[0] = 27;
     space   = H5Screate_simple(1, dims, NULL);
     attr    = H5Acreate2(dataset, "attr1", H5T_STD_I8BE, space, H5P_DEFAULT, H5P_DEFAULT);
-    HDsprintf(buf, "1st attribute of dset1.1.1");
+    HDsnprintf(buf, sizeof(buf), "1st attribute of dset1.1.1");
     H5Awrite(attr, H5T_NATIVE_SCHAR, buf);
     H5Sclose(space);
     H5Aclose(attr);
@@ -1426,7 +1426,7 @@ gent_all(void)
     dims[0] = 27;
     space   = H5Screate_simple(1, dims, NULL);
     attr    = H5Acreate2(dataset, "attr2", H5T_STD_I8BE, space, H5P_DEFAULT, H5P_DEFAULT);
-    HDsprintf(buf, "2nd attribute of dset1.1.1");
+    HDsnprintf(buf, sizeof(buf), "2nd attribute of dset1.1.1");
     H5Awrite(attr, H5T_NATIVE_SCHAR, buf);
     H5Sclose(space);
     H5Aclose(attr);
@@ -1625,7 +1625,7 @@ gent_many(void)
     dims[0] = 10;
     space2  = H5Screate_simple(1, dims, NULL);
     attr    = H5Acreate2(dataset, "attr1", H5T_STD_I8BE, space2, H5P_DEFAULT, H5P_DEFAULT);
-    HDsprintf(buf, "abcdefghi");
+    HDsnprintf(buf, sizeof(buf), "abcdefghi");
     H5Awrite(attr, H5T_NATIVE_CHAR, buf);
     H5Sclose(space2);
     H5Aclose(attr);
@@ -1963,9 +1963,9 @@ gent_str2(void)
     dims[0] = 3;
     space2  = H5Screate_simple(1, dims, NULL);
     attr    = H5Acreate2(dataset, "attr1", fxdlenstr2, space2, H5P_DEFAULT, H5P_DEFAULT);
-    HDsprintf(&(buf2[0 * LENSTR2]), "0123456789");
-    HDsprintf(&(buf2[1 * LENSTR2]), "abcdefghij");
-    HDsprintf(&(buf2[2 * LENSTR2]), "ABCDEFGHIJ");
+    HDsnprintf(&(buf2[0 * LENSTR2]), LENSTR2, "0123456789");
+    HDsnprintf(&(buf2[1 * LENSTR2]), LENSTR2, "abcdefghij");
+    HDsnprintf(&(buf2[2 * LENSTR2]), LENSTR2, "ABCDEFGHIJ");
     H5Awrite(attr, fxdlenstr2, buf2);
     H5Sclose(space2);
     H5Tclose(fxdlenstr2);
@@ -1977,7 +1977,7 @@ gent_str2(void)
 
     for (i = 0; (hsize_t)i < sdim; i++) {
         start[0] = (hsize_t)i;
-        HDsprintf(buf, "This is row %1d of type H5T_STR_NULLTERM of", i);
+        HDsnprintf(buf, sizeof(buf), "This is row %1d of type H5T_STR_NULLTERM of", i);
         H5Tset_size(memtype, HDstrlen(buf) + 1);
         H5Sselect_hyperslab(hyper_space, H5S_SELECT_SET, start, stride, count, block);
         H5Dwrite(dataset, memtype, mem_space, hyper_space, H5P_DEFAULT, buf);
@@ -1990,7 +1990,7 @@ gent_str2(void)
 
     for (i = 0; (hsize_t)i < sdim; i++) {
         start[0] = (hsize_t)i;
-        HDsprintf(buf, "This is row %1d of type H5T_STR_NULLTERM of string array", i);
+        HDsnprintf(buf, sizeof(buf), "This is row %1d of type H5T_STR_NULLTERM of string array", i);
         H5Tset_size(memtype, HDstrlen(buf) + 1);
         H5Sselect_hyperslab(hyper_space, H5S_SELECT_SET, start, stride, count, block);
         H5Dwrite(dataset, memtype, mem_space, hyper_space, H5P_DEFAULT, buf);
@@ -2009,7 +2009,7 @@ gent_str2(void)
 
     for (i = 0; (hsize_t)i < sdim; i++) {
         start[0] = (hsize_t)i;
-        HDsprintf(buf, "This is row %1d of type H5T_STR_NULLPAD of", i);
+        HDsnprintf(buf, sizeof(buf), "This is row %1d of type H5T_STR_NULLPAD of", i);
         H5Tset_size(memtype, HDstrlen(buf) + 1);
         H5Sselect_hyperslab(hyper_space, H5S_SELECT_SET, start, stride, count, block);
         H5Dwrite(dataset, memtype, mem_space, hyper_space, H5P_DEFAULT, buf);
@@ -2022,7 +2022,7 @@ gent_str2(void)
 
     for (i = 0; (hsize_t)i < sdim; i++) {
         start[0] = (hsize_t)i;
-        HDsprintf(buf, "This is row %1d of type H5T_STR_NULLPAD of string array", i);
+        HDsnprintf(buf, sizeof(buf), "This is row %1d of type H5T_STR_NULLPAD of string array", i);
         H5Tset_size(memtype, HDstrlen(buf) + 1);
         H5Sselect_hyperslab(hyper_space, H5S_SELECT_SET, start, stride, count, block);
         H5Dwrite(dataset, memtype, mem_space, hyper_space, H5P_DEFAULT, buf);
@@ -2041,7 +2041,7 @@ gent_str2(void)
 
     for (i = 0; (hsize_t)i < sdim; i++) {
         start[0] = (hsize_t)i;
-        HDsprintf(buf, "This is row %1d of type H5T_STR_SPACEPAD of", i);
+        HDsnprintf(buf, sizeof(buf), "This is row %1d of type H5T_STR_SPACEPAD of", i);
         H5Tset_size(memtype, HDstrlen(buf) + 1);
         H5Sselect_hyperslab(hyper_space, H5S_SELECT_SET, start, stride, count, block);
         H5Dwrite(dataset, memtype, mem_space, hyper_space, H5P_DEFAULT, buf);
@@ -2054,7 +2054,7 @@ gent_str2(void)
 
     for (i = 0; (hsize_t)i < sdim; i++) {
         start[0] = (hsize_t)i;
-        HDsprintf(buf, "This is row %1d of type H5T_STR_SPACEPAD of string array", i);
+        HDsnprintf(buf, sizeof(buf), "This is row %1d of type H5T_STR_SPACEPAD of string array", i);
         H5Tset_size(memtype, HDstrlen(buf) + 1);
         H5Sselect_hyperslab(hyper_space, H5S_SELECT_SET, start, stride, count, block);
         H5Dwrite(dataset, memtype, mem_space, hyper_space, H5P_DEFAULT, buf);
@@ -3923,7 +3923,7 @@ gent_large_objname(void)
     group = H5Gcreate2(fid, "this_is_a_large_group_name", H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
 
     for (i = 0; i < 50; ++i) {
-        HDsprintf(grp_name, "this_is_a_large_group_name%d", i);
+        HDsnprintf(grp_name, sizeof(grp_name), "this_is_a_large_group_name%d", i);
         group2 = H5Gcreate2(group, grp_name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         H5Gclose(group2);
     }
diff --git a/tools/test/h5jam/h5jamgentest.c b/tools/test/h5jam/h5jamgentest.c
index 5632cc0..16604b3 100644
--- a/tools/test/h5jam/h5jamgentest.c
+++ b/tools/test/h5jam/h5jamgentest.c
@@ -152,7 +152,7 @@ gent_ub(const char *filename, size_t ub_size, size_t ub_fill)
         goto error;
     if ((attr = H5Acreate2(group, "attr1", H5T_STD_I8BE, space, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         goto error;
-    if (HDsprintf(buf, "abcdefghi") < 0)
+    if (HDsnprintf(buf, sizeof(buf), "abcdefghi") < 0)
         goto error;
     if (H5Awrite(attr, H5T_NATIVE_SCHAR, buf) < 0)
         goto error;
@@ -206,7 +206,7 @@ gent_ub(const char *filename, size_t ub_size, size_t ub_fill)
         goto error;
     if ((attr = H5Acreate2(dataset, "attr1", H5T_STD_I8BE, space, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         goto error;
-    if (HDsprintf(buf, "1st attribute of dset1.1.1") < 0)
+    if (HDsnprintf(buf, sizeof(buf), "1st attribute of dset1.1.1") < 0)
         goto error;
     if (H5Awrite(attr, H5T_NATIVE_SCHAR, buf) < 0)
         goto error;
@@ -220,7 +220,7 @@ gent_ub(const char *filename, size_t ub_size, size_t ub_fill)
         goto error;
     if ((attr = H5Acreate2(dataset, "attr2", H5T_STD_I8BE, space, H5P_DEFAULT, H5P_DEFAULT)) < 0)
         goto error;
-    if (HDsprintf(buf, "2nd attribute of dset1.1.1") < 0)
+    if (HDsnprintf(buf, sizeof(buf), "2nd attribute of dset1.1.1") < 0)
         goto error;
     if (H5Awrite(attr, H5T_NATIVE_SCHAR, buf) < 0)
         goto error;
diff --git a/tools/test/h5repack/h5repacktst.c b/tools/test/h5repack/h5repacktst.c
index 8b114e4..028939a 100644
--- a/tools/test/h5repack/h5repacktst.c
+++ b/tools/test/h5repack/h5repacktst.c
@@ -3157,7 +3157,7 @@ make_early(void)
             goto out;
         if ((tid = H5Tcopy(H5T_NATIVE_DOUBLE)) < 0)
             goto out;
-        HDsprintf(name, "%d", i);
+        HDsnprintf(name, sizeof(name), "%d", i);
         if ((H5Tcommit2(fid, name, tid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             goto out;
         if (H5Tclose(tid) < 0)
@@ -3181,7 +3181,7 @@ make_early(void)
     for (i = 0; i < iter; i++) {
         if ((tid = H5Tcopy(H5T_NATIVE_DOUBLE)) < 0)
             goto out;
-        HDsprintf(name, "%d", i);
+        HDsnprintf(name, sizeof(name), "%d", i);
         if ((H5Tcommit2(fid, name, tid, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             goto out;
         if (H5Tclose(tid) < 0)
@@ -3240,7 +3240,7 @@ make_layout(hid_t loc_id)
      *-------------------------------------------------------------------------
      */
     for (i = 0; i < 4; i++) {
-        HDsprintf(name, "dset%d", i + 1);
+        HDsnprintf(name, sizeof(name), "dset%d", i + 1);
         if (write_dset(loc_id, RANK, dims, name, H5T_NATIVE_INT, buf) < 0)
             goto error;
     }
diff --git a/tools/test/h5stat/h5stat_gentest.c b/tools/test/h5stat/h5stat_gentest.c
index c775d6a..4d21a43 100644
--- a/tools/test/h5stat/h5stat_gentest.c
+++ b/tools/test/h5stat/h5stat_gentest.c
@@ -88,7 +88,7 @@ gen_newgrat_file(const char *fname)
 
     /* Create NUM_GRPS groups in the root group */
     for (i = 1; i <= NUM_GRPS; i++) {
-        HDsprintf(name, "%s%d", GROUP_NAME, i);
+        HDsnprintf(name, sizeof(name), "%s%d", GROUP_NAME, i);
         if ((gid = H5Gcreate2(fid, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             goto error;
         if (H5Gclose(gid) < 0)
@@ -109,7 +109,7 @@ gen_newgrat_file(const char *fname)
 
     /* Create NUM_ATTRS for the dataset */
     for (i = 1; i <= NUM_ATTRS; i++) {
-        HDsprintf(attrname, "%s%d", ATTR_NAME, i);
+        HDsnprintf(attrname, sizeof(attrname), "%s%d", ATTR_NAME, i);
         if ((attr_id = H5Acreate2(did, attrname, tid, sid, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             goto error;
         if (H5Aclose(attr_id) < 0)
@@ -211,7 +211,7 @@ gen_threshold_file(const char *fname)
 
     /* Create 11 attributes for the dataset */
     for (i = 1; i <= (THRES_NUM + 1); i++) {
-        HDsprintf(name, "%s%d", THRES_ATTR_NAME, i);
+        HDsnprintf(name, sizeof(name), "%s%d", THRES_ATTR_NAME, i);
         if ((attr_id = H5Acreate2(did, name, H5T_NATIVE_INT, sid1, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             goto error;
         if (H5Aclose(attr_id) < 0)
@@ -240,7 +240,7 @@ gen_threshold_file(const char *fname)
 
     /* Create 10 attributes for the 2-D dataset */
     for (i = 1; i <= THRES_NUM; i++) {
-        HDsprintf(name, "%s%d", THRES_ATTR_NAME, i);
+        HDsnprintf(name, sizeof(name), "%s%d", THRES_ATTR_NAME, i);
         if ((attr_id = H5Acreate2(did, name, H5T_NATIVE_INT, sid1, H5P_DEFAULT, H5P_DEFAULT)) < 0)
             goto error;
         if (H5Aclose(attr_id) < 0)
@@ -264,7 +264,7 @@ gen_threshold_file(const char *fname)
     /* Create 10 1-D datasets with non-zero dimension size for the group */
     for (i = 1; i <= THRES_NUM; i++) {
         /* set up dataset name */
-        HDsprintf(name, "%s%d", THRES_DSET_NAME, i);
+        HDsnprintf(name, sizeof(name), "%s%d", THRES_DSET_NAME, i);
 
         /* Create the dataset */
         if ((did = H5Dcreate2(gid, name, H5T_NATIVE_UCHAR, sid1, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
@@ -286,7 +286,7 @@ gen_threshold_file(const char *fname)
     /* Create 25 attributes for the group */
     for (i = 1; i <= THRES_NUM_25; i++) {
         /* Set up attribute name */
-        HDsprintf(name, "%s%d", THRES_ATTR_GRP_NAME, i);
+        HDsnprintf(name, sizeof(name), "%s%d", THRES_ATTR_GRP_NAME, i);
 
         /* Create the attribute */
         if ((attr_id = H5Acreate2(gid, name, H5T_NATIVE_INT, sid2, H5P_DEFAULT, H5P_DEFAULT)) < 0)
@@ -308,7 +308,7 @@ gen_threshold_file(const char *fname)
     /* Create 9 1-D datasets with non-zero dimension size for the group */
     for (i = 1; i < THRES_NUM; i++) {
         /* set up dataset name */
-        HDsprintf(name, "%s%d", THRES_DSET_NAME, i);
+        HDsnprintf(name, sizeof(name), "%s%d", THRES_DSET_NAME, i);
 
         /* Create the dataset */
         if ((did = H5Dcreate2(gid, name, H5T_NATIVE_UCHAR, sid1, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT)) < 0)
diff --git a/tools/test/misc/h5perf_gentest.c b/tools/test/misc/h5perf_gentest.c
index 248fd92..7589144 100644
--- a/tools/test/misc/h5perf_gentest.c
+++ b/tools/test/misc/h5perf_gentest.c
@@ -104,7 +104,7 @@ main(int argc, char *argv[])
     }
 
     if (strlen(fname) <= 0)
-        HDsprintf(fname, FNAME);
+        HDsnprintf(fname, sizeof(fname), FNAME);
 
     create_perf_test_file(fname, ngrps, ndsets, nattrs, (hsize_t)nrows, (hsize_t)dim0, (hsize_t)chunk, vlen,
                           z, l);
@@ -324,7 +324,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         fid = H5Fcreate(fname, H5F_ACC_TRUNC, H5P_DEFAULT, H5P_DEFAULT);
     add_attrs(fid, 0);
 
-    HDsprintf(name, "a cmp ds of %d rows", nrows);
+    HDsnprintf(name, sizeof(name), "a cmp ds of %d rows", nrows);
     did = H5Dcreate(fid, name, cmp_tid, sid_large, H5P_DEFAULT, dcpl, H5P_DEFAULT);
     H5Dwrite(did, cmp_tid, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_comp_large);
     add_attrs(did, 0);
@@ -344,7 +344,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
     add_attrs(gid1, 0);
     for (i = 0; i < ngrps; i++) {
         /* create sub groups */
-        HDsprintf(name, "g%02d", i);
+        HDsnprintf(name, sizeof(name), "g%02d", i);
         gid2 = H5Gcreate(gid1, name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         if (i < 10)
             add_attrs(gid2, 0);
@@ -357,14 +357,14 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
     add_attrs(gid1, 0);
     for (j = 0; j < ndsets; j += 12) {
         /* 1 add a null dataset */
-        HDsprintf(name, "%05d null dataset", j);
+        HDsnprintf(name, sizeof(name), "%05d null dataset", j);
         did = H5Dcreate(gid1, name, H5T_STD_I32LE, sid_null, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         if (!j)
             add_attrs(did, j);
         H5Dclose(did);
 
         /* 2 add scalar int point */
-        HDsprintf(name, "%05d scalar int point", j);
+        HDsnprintf(name, sizeof(name), "%05d scalar int point", j);
         did = H5Dcreate(gid1, name, H5T_NATIVE_INT, sid_scalar, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         H5Dwrite(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, &j);
         if (!j)
@@ -372,7 +372,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Dclose(did);
 
         /* 3 scalar vlen string */
-        HDsprintf(name, "%05d scalar vlen string", j);
+        HDsnprintf(name, sizeof(name), "%05d scalar vlen string", j);
         did = H5Dcreate(gid1, name, tid_vlen_s, sid_scalar, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         H5Dwrite(did, tid_vlen_s, H5S_ALL, H5S_ALL, H5P_DEFAULT, &buf_vlen_s[0]);
         if (!j)
@@ -380,7 +380,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Dclose(did);
 
         /* 4 add fixed-length float array */
-        HDsprintf(name, "%05d fixed-length float array", j);
+        HDsnprintf(name, sizeof(name), "%05d fixed-length float array", j);
         did = H5Dcreate(gid1, name, tid_array_f, sid_1d, H5P_DEFAULT, dcpl, H5P_DEFAULT);
         H5Dwrite(did, tid_array_f, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_float_a);
         if (!j)
@@ -388,7 +388,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Dclose(did);
 
         /* 5 add fixed-length strings */
-        HDsprintf(name, "%05d fixed-length strings", j);
+        HDsnprintf(name, sizeof(name), "%05d fixed-length strings", j);
         did = H5Dcreate(gid1, name, tid_str, sid_1d, H5P_DEFAULT, dcpl, H5P_DEFAULT);
         H5Dwrite(did, tid_str, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_str);
         if (!j)
@@ -396,7 +396,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Dclose(did);
 
         /* 6 add compound data */
-        HDsprintf(name, "%05d compound data", j);
+        HDsnprintf(name, sizeof(name), "%05d compound data", j);
         did = H5Dcreate(gid1, name, cmp_tid, sid_1d, H5P_DEFAULT, dcpl, H5P_DEFAULT);
         H5Dwrite(did, cmp_tid, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_comp);
         if (!j)
@@ -404,7 +404,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Dclose(did);
 
         /* 7 add 2D double */
-        HDsprintf(name, "%05d 2D double", j);
+        HDsnprintf(name, sizeof(name), "%05d 2D double", j);
         strcpy(tmp_name1, name);
         did = H5Dcreate(gid1, name, H5T_NATIVE_DOUBLE, sid_2d, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         H5Dwrite(did, H5T_NATIVE_DOUBLE, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_double2d[0]);
@@ -413,7 +413,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Dclose(did);
 
         /* 8 add 1D int array */
-        HDsprintf(name, "%05d 1D int array", j);
+        HDsnprintf(name, sizeof(name), "%05d 1D int array", j);
         did = H5Dcreate(gid1, name, H5T_NATIVE_INT, sid_1d, H5P_DEFAULT, dcpl, H5P_DEFAULT);
         H5Dwrite(did, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_int);
         if (!j)
@@ -421,7 +421,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Dclose(did);
 
         /* 9 add vlen int array */
-        HDsprintf(name, "%05d vlen int array", j);
+        HDsnprintf(name, sizeof(name), "%05d vlen int array", j);
         strcpy(tmp_name2, name);
         did = H5Dcreate(gid1, name, tid_vlen_i, sid_1d, H5P_DEFAULT, dcpl, H5P_DEFAULT);
         H5Dwrite(did, tid_vlen_i, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_vlen_i);
@@ -430,7 +430,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Dclose(did);
 
         /* 10 add vlen strings */
-        HDsprintf(name, "%05d vlen strings", j);
+        HDsnprintf(name, sizeof(name), "%05d vlen strings", j);
         strcpy(tmp_name3, name);
         did = H5Dcreate(gid1, name, tid_vlen_s, sid_1d, H5P_DEFAULT, dcpl, H5P_DEFAULT);
         H5Dwrite(did, tid_vlen_s, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_vlen_s);
@@ -441,7 +441,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         /* 11 add object refs */
         H5Rcreate(&buf_ref[0], gid1, ".", H5R_OBJECT, (hid_t)-1);
         H5Rcreate(&buf_ref[1], gid1, tmp_name3, H5R_OBJECT, (hid_t)-1);
-        HDsprintf(name, "%05d obj refs", j);
+        HDsnprintf(name, sizeof(name), "%05d obj refs", j);
         did = H5Dcreate(gid1, name, H5T_STD_REF_OBJ, sid_2, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         H5Dwrite(did, H5T_STD_REF_OBJ, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_ref);
         if (!j)
@@ -456,7 +456,7 @@ create_perf_test_file(const char *fname, int ngrps, int ndsets, int nattrs, hsiz
         H5Sselect_hyperslab(sid_1d, H5S_SELECT_SET, &start, &stride, &count, NULL);
         H5Rcreate(&buf_reg_ref[1], gid1, tmp_name2, H5R_DATASET_REGION, sid_1d);
         H5Sselect_none(sid_1d);
-        HDsprintf(name, "%05d region refs", j);
+        HDsnprintf(name, sizeof(name), "%05d region refs", j);
         did = H5Dcreate(gid1, name, H5T_STD_REF_DSETREG, sid_2, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);
         H5Dwrite(did, H5T_STD_REF_DSETREG, H5S_ALL, H5S_ALL, H5P_DEFAULT, buf_reg_ref);
         if (!j)
@@ -572,11 +572,11 @@ add_attrs(hid_t oid, int idx)
 
     /* 1 scalar point */
     sid = H5Screate(H5S_SCALAR);
-    HDsprintf(name, "%05d scalar int", idx);
+    HDsnprintf(name, sizeof(name), "%05d scalar int", idx);
     nattrs += add_attr(oid, name, H5T_NATIVE_UINT, sid, &i);
-    HDsprintf(name, "%05d scalar ulong", idx);
+    HDsnprintf(name, sizeof(name), "%05d scalar ulong", idx);
     nattrs += add_attr(oid, name, H5T_NATIVE_INT64, sid, &l);
-    HDsprintf(name, "%05d scalar str", idx);
+    HDsnprintf(name, sizeof(name), "%05d scalar str", idx);
     tid = H5Tcopy(H5T_C_S1);
     H5Tset_size(tid, H5T_VARIABLE);
     nattrs += add_attr(oid, name, tid, sid, &s[2]);
@@ -586,24 +586,24 @@ add_attrs(hid_t oid, int idx)
     /* 4 single point */
     sid = H5Screate_simple(1, dims1, NULL);
     H5Rcreate(&ref, oid, ".", H5R_OBJECT, (hid_t)-1);
-    HDsprintf(name, "%05d single float", idx);
+    HDsnprintf(name, sizeof(name), "%05d single float", idx);
     nattrs += add_attr(oid, name, H5T_NATIVE_FLOAT, sid, &f);
-    HDsprintf(name, "%05d single double", idx);
+    HDsnprintf(name, sizeof(name), "%05d single double", idx);
     nattrs += add_attr(oid, name, H5T_NATIVE_DOUBLE, sid, &d);
-    HDsprintf(name, "%05d single obj_ref", idx);
+    HDsnprintf(name, sizeof(name), "%05d single obj_ref", idx);
     nattrs += add_attr(oid, name, H5T_STD_REF_OBJ, sid, &ref);
     H5Sclose(sid);
 
     /* 7 fixed length 1D array */
     sid = H5Screate_simple(1, dims1, NULL);
     tid = H5Tarray_create(H5T_NATIVE_FLOAT, 1, dims2);
-    HDsprintf(name, "%05d array float", idx);
+    HDsnprintf(name, sizeof(name), "%05d array float", idx);
     nattrs += add_attr(oid, name, tid, sid, &f_array[0]);
     H5Tclose(tid);
     tid = H5Tcopy(H5T_C_S1);
     H5Tset_size(tid, strlen(s[0]) + 1);
     tid1 = H5Tarray_create(tid, 1, dims2);
-    HDsprintf(name, "%05d array str", idx);
+    HDsnprintf(name, sizeof(name), "%05d array str", idx);
     nattrs += add_attr(oid, name, tid1, sid, s);
     H5Tclose(tid1);
     H5Tclose(tid);
@@ -612,7 +612,7 @@ add_attrs(hid_t oid, int idx)
     /* 9 fixed length 2D int arrays */
     sid = H5Screate_simple(1, dims2, NULL);
     tid = H5Tarray_create(H5T_NATIVE_INT, 2, dims3);
-    HDsprintf(name, "%05d array int 2D", idx);
+    HDsnprintf(name, sizeof(name), "%05d array int 2D", idx);
     nattrs += add_attr(oid, name, tid, sid, int3d[0][0]);
     H5Tclose(tid);
     H5Sclose(sid);
@@ -621,12 +621,12 @@ add_attrs(hid_t oid, int idx)
     sid = H5Screate_simple(1, dims2, NULL);
     tid = H5Tcopy(H5T_C_S1);
     H5Tset_size(tid, H5T_VARIABLE);
-    HDsprintf(name, "%05d vlen strings", idx);
+    HDsnprintf(name, sizeof(name), "%05d vlen strings", idx);
     nattrs += add_attr(oid, name, tid, sid, s_vlen);
     H5Tclose(tid);
     tid = H5Tvlen_create(H5T_NATIVE_INT);
     ;
-    HDsprintf(name, "%05d vlen int array", idx);
+    HDsnprintf(name, sizeof(name), "%05d vlen int array", idx);
     nattrs += add_attr(oid, name, tid, sid, i_vlen);
     H5Tclose(tid);
     H5Sclose(sid);
@@ -640,7 +640,7 @@ add_attrs(hid_t oid, int idx)
     offset += sizeof(H5T_NATIVE_INT);
     H5Tinsert(tid, "City", offset, tid1);
     offset += sizeof(char *);
-    HDsprintf(name, "%05d compound data", idx);
+    HDsnprintf(name, sizeof(name), "%05d compound data", idx);
     nattrs += add_attr(oid, name, tid, sid, cmp_data);
     H5Tclose(tid1);
     H5Tclose(tid);
diff --git a/tools/test/perform/iopipe.c b/tools/test/perform/iopipe.c
index 2aa9e25..37f07a1 100644
--- a/tools/test/perform/iopipe.c
+++ b/tools/test/perform/iopipe.c
@@ -71,7 +71,7 @@ print_stats(const char *prefix,
              ((double)(r_start->ru_stime.tv_sec) + (double)(r_start->ru_stime.tv_usec) / 1000000.0);
 #endif
     e_time = t_stop - t_start;
-    H5_bandwidth(bw, (double)nbytes, e_time);
+    H5_bandwidth(bw, sizeof(bw), (double)nbytes, e_time);
 
 #ifdef H5_HAVE_GETRUSAGE
     HDprintf(HEADING "%1.2fuser %1.2fsystem %1.2felapsed %s\n", prefix, u_time, s_time, e_time, bw);