diff --git a/c++/test/dsets.cpp b/c++/test/dsets.cpp
index d61389b084..949c8161c0 100644
--- a/c++/test/dsets.cpp
+++ b/c++/test/dsets.cpp
@@ -1457,6 +1457,8 @@ test_dset(const void *params)
     fapl_id     = h5_fileaccess(); // in h5test.c, returns a file access template
     int nerrors = 0;               // keep track of number of failures occur
 
+    (void)params;
+
     try {
         // Use the file access template id to create a file access prop.
         // list object to pass in H5File::H5File
@@ -1505,6 +1507,8 @@ test_dset(const void *params)
 extern "C" void
 cleanup_dsets(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILE1.c_str());
         HDremove(FILE_ACCPLIST.c_str());
diff --git a/c++/test/tarray.cpp b/c++/test/tarray.cpp
index 9be2e5c85c..4fbc8c9177 100644
--- a/c++/test/tarray.cpp
+++ b/c++/test/tarray.cpp
@@ -479,6 +479,8 @@ test_array_info()
 extern "C" void
 test_array(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Array Datatypes\n"));
 
@@ -504,6 +506,8 @@ test_array(const void *params)
 extern "C" void
 cleanup_array(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILENAME.c_str());
     }
diff --git a/c++/test/tattr.cpp b/c++/test/tattr.cpp
index dec3397259..51932f2674 100644
--- a/c++/test/tattr.cpp
+++ b/c++/test/tattr.cpp
@@ -1958,6 +1958,8 @@ test_attr_corder_create_basic(FileCreatPropList &fcpl, FileAccPropList &fapl)
 extern "C" void
 test_attr(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Attributes\n"));
 
@@ -2043,6 +2045,8 @@ test_attr(const void *params)
 extern "C" void
 cleanup_attr(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILE_BASIC.c_str());
         HDremove(FILE_COMPOUND.c_str());
diff --git a/c++/test/tcompound.cpp b/c++/test/tcompound.cpp
index 29d3120bc5..5e73d42a7b 100644
--- a/c++/test/tcompound.cpp
+++ b/c++/test/tcompound.cpp
@@ -731,6 +731,8 @@ test_compound_set_size()
 extern "C" void
 test_compound(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Compound Data Type operations\n"));
 
@@ -755,6 +757,8 @@ test_compound(const void *params)
 extern "C" void
 cleanup_compound(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(COMPFILE.c_str());
     }
diff --git a/c++/test/tdspl.cpp b/c++/test/tdspl.cpp
index fc261db150..0982b30413 100644
--- a/c++/test/tdspl.cpp
+++ b/c++/test/tdspl.cpp
@@ -116,6 +116,8 @@ test_transfplist()
 extern "C" void
 test_dsproplist(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Generic Dataset Property Lists\n"));
 
@@ -134,6 +136,8 @@ test_dsproplist(const void *params)
 extern "C" void
 cleanup_dsproplist(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILENAME.c_str());
     }
diff --git a/c++/test/tfile.cpp b/c++/test/tfile.cpp
index 3f1f811523..250be27e1d 100644
--- a/c++/test/tfile.cpp
+++ b/c++/test/tfile.cpp
@@ -970,6 +970,8 @@ test_file_info()
 extern "C" void
 test_file(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing File I/O Operations\n"));
 
@@ -992,12 +994,11 @@ test_file(const void *params)
  * Return       none
  *-------------------------------------------------------------------------
  */
-#ifdef __cplusplus
-extern "C"
-#endif
-    void
-    cleanup_file(void *params)
+extern "C" void
+cleanup_file(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILE1.c_str());
         HDremove(FILE2.c_str());
diff --git a/c++/test/tfilter.cpp b/c++/test/tfilter.cpp
index 9d426c1e2e..c46a2217ef 100644
--- a/c++/test/tfilter.cpp
+++ b/c++/test/tfilter.cpp
@@ -229,6 +229,8 @@ const H5std_string FILE1("tfilters.h5");
 extern "C" void
 test_filters(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Various Filters\n"));
 
@@ -261,6 +263,8 @@ test_filters(const void *params)
 extern "C" void
 cleanup_filters(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILE1.c_str());
     }
diff --git a/c++/test/th5s.cpp b/c++/test/th5s.cpp
index 8b18ec011f..2953a4c08d 100644
--- a/c++/test/th5s.cpp
+++ b/c++/test/th5s.cpp
@@ -473,6 +473,8 @@ test_h5s_compound_scalar_read()
 extern "C" void
 test_h5s(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Dataspaces\n"));
 
@@ -495,6 +497,8 @@ test_h5s(const void *params)
 extern "C" void
 cleanup_h5s(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(DATAFILE.c_str());
     }
diff --git a/c++/test/titerate.cpp b/c++/test/titerate.cpp
index 593ba50797..de27a9eaaa 100644
--- a/c++/test/titerate.cpp
+++ b/c++/test/titerate.cpp
@@ -442,6 +442,8 @@ test_HDFFV_9920()
 extern "C" void
 test_iterate(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Iterate Feature\n"));
 
@@ -466,6 +468,8 @@ test_iterate(const void *params)
 extern "C" void
 cleanup_iterate(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILE_ITERATE.c_str());
         HDremove(FILE_NAME.c_str());
diff --git a/c++/test/tlinks.cpp b/c++/test/tlinks.cpp
index ec6f8eee21..c76291d742 100644
--- a/c++/test/tlinks.cpp
+++ b/c++/test/tlinks.cpp
@@ -714,6 +714,8 @@ test_links(const void *params)
     hid_t    fapl_id, fapl2_id; /* File access property lists */
     unsigned new_format;        /* Whether to use the new format or not */
 
+    (void)params;
+
     if ((fapl_id = h5_fileaccess()) < 0)
         throw Exception("test_links", "Unable to get file access property list");
 
@@ -771,6 +773,8 @@ test_links(const void *params)
 extern "C" void
 cleanup_links(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILENAME[0]);
         HDremove(FILENAME[1]);
diff --git a/c++/test/tobject.cpp b/c++/test/tobject.cpp
index adf7c58abd..5b29df38c3 100644
--- a/c++/test/tobject.cpp
+++ b/c++/test/tobject.cpp
@@ -512,8 +512,6 @@ test_open_object_header()
  *              file will return the same file "number".
  *
  * Return       None
- *
- * July, 2018
  *-------------------------------------------------------------------------
  */
 const H5std_string FILE_OBJINFO("tobject_getinfo.h5");
@@ -599,8 +597,6 @@ test_getobjectinfo_same_file()
  *              the property setting.
  *
  * Return       None
- *
- * April, 2019
  *-------------------------------------------------------------------------
  */
 const H5std_string FILE_INTERGRPS("tobject_intergrps.h5");
@@ -713,13 +709,13 @@ test_intermediate_groups()
  *
  * Return       Success: 0
  *              Failure: -1
- *
- * March 4, 2014
  *-------------------------------------------------------------------------
  */
 extern "C" void
 test_object(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Object Functions\n"));
 
@@ -744,6 +740,8 @@ test_object(const void *params)
 extern "C" void
 cleanup_object(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILE_OBJECTS.c_str());
         HDremove(FILE_OBJHDR.c_str());
diff --git a/c++/test/trefer.cpp b/c++/test/trefer.cpp
index 4a9a2f0447..83224eb318 100644
--- a/c++/test/trefer.cpp
+++ b/c++/test/trefer.cpp
@@ -829,6 +829,8 @@ test_reference_region_1D()
 extern "C" void
 test_reference(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing References\n"));
 
@@ -850,6 +852,8 @@ test_reference(const void *params)
 extern "C" void
 cleanup_reference(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILE1.c_str());
         HDremove(FILE2.c_str());
diff --git a/c++/test/ttypes.cpp b/c++/test/ttypes.cpp
index 1959331c59..5bac64cb37 100644
--- a/c++/test/ttypes.cpp
+++ b/c++/test/ttypes.cpp
@@ -1095,6 +1095,8 @@ test_operators()
 extern "C" void
 test_types(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Generic Data Types\n"));
 
@@ -1122,6 +1124,8 @@ test_types(const void *params)
 extern "C" void
 cleanup_types(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         for (int i = 0; i < 6; i++)
             HDremove(FILENAME[i]);
diff --git a/c++/test/tvlstr.cpp b/c++/test/tvlstr.cpp
index db616cd057..cfd37632ee 100644
--- a/c++/test/tvlstr.cpp
+++ b/c++/test/tvlstr.cpp
@@ -936,6 +936,8 @@ test_vl_rewrite()
 extern "C" void
 test_vlstrings(const void *params)
 {
+    (void)params;
+
     // Output message about test being performed
     MESSAGE(5, ("Testing Variable-Length Strings"));
 
@@ -969,6 +971,8 @@ test_vlstrings(const void *params)
 extern "C" void
 cleanup_vlstrings(void *params)
 {
+    (void)params;
+
     if (GetTestCleanup()) {
         HDremove(FILENAME.c_str());
         HDremove(FILENAME2.c_str());