Various clang tidy warning fixes (#448)

* Fixed clang-tidy bugprone-reserved-identifier warnings

* Fixed clang-tidy bugprone-assert-side-effect warnings

* Fixed clang-tidy bugprone-copy-constructor-init warning

* Fixed clang-tidy readability-redundant-preprocessor warning

For error_test.c the removed code was already dead, because it was in the else of an `#if H5_USE_16_API` block.

Based on H5Location.h, I think p_get_ref_obj_type was meant to be in `#ifndef DOXYGEN_SHOULD_SKIP_THIS` and an `#endif` was missing.  Similarly, in the header, getObjTypeByIdx is only in H5_NO_DEPRECATED_SYMBOLS, not DOXYGEN_SHOULD_SKIP_THIS.

* Fixed clang-tidy readability-redundant-string-init warnings

* Fixed some clang-tidy performance-type-promotion-in-math-fn warnings

* Fixed clang-tidy performance-unnecessary-value-param warnings

* Reformat source with clang v10.0.1.

Co-authored-by: Larry Knox <lrknox@hdfgroup.org>

23 files changed, 119 insertions, 125 deletions

diff --git a/c++/src/H5Attribute.cpp b/c++/src/H5Attribute.cpp
index d893fec..b74349c 100644
--- a/c++/src/H5Attribute.cpp
+++ b/c++/src/H5Attribute.cpp
@@ -308,7 +308,7 @@ Attribute::getName(char *attr_name, size_t buf_size) const
 H5std_string
 Attribute::getName() const
 {
-    H5std_string attr_name(""); // attribute name to return
+    H5std_string attr_name; // attribute name to return
 
     // Preliminary call to get the size of the attribute name
     ssize_t name_size = H5Aget_name(id, static_cast<size_t>(0), NULL);
diff --git a/c++/src/H5DcreatProp.cpp b/c++/src/H5DcreatProp.cpp
index d670b74..0ffcbf7 100644
--- a/c++/src/H5DcreatProp.cpp
+++ b/c++/src/H5DcreatProp.cpp
@@ -769,8 +769,8 @@ DSetCreatPropList::setVirtual(const DataSpace &vspace, const char *src_fname, co
 // Programmer   Binh-Minh Ribler - Mar, 2017
 //--------------------------------------------------------------------------
 void
-DSetCreatPropList::setVirtual(const DataSpace &vspace, const H5std_string src_fname,
-                              const H5std_string src_dsname, const DataSpace &sspace) const
+DSetCreatPropList::setVirtual(const DataSpace &vspace, const H5std_string &src_fname,
+                              const H5std_string &src_dsname, const DataSpace &sspace) const
 {
     setVirtual(vspace, src_fname.c_str(), src_dsname.c_str(), sspace);
 }
diff --git a/c++/src/H5DcreatProp.h b/c++/src/H5DcreatProp.h
index 3c032ee..820c0d1 100644
--- a/c++/src/H5DcreatProp.h
+++ b/c++/src/H5DcreatProp.h
@@ -123,7 +123,7 @@ class H5_DLLCPP DSetCreatPropList : public ObjCreatPropList {
     // Maps elements of a virtual dataset to elements of the source dataset.
     void setVirtual(const DataSpace &vspace, const char *src_fname, const char *src_dsname,
                     const DataSpace &sspace) const;
-    void setVirtual(const DataSpace &vspace, const H5std_string src_fname, const H5std_string src_dsname,
+    void setVirtual(const DataSpace &vspace, const H5std_string &src_fname, const H5std_string &src_dsname,
                     const DataSpace &sspace) const;
 
     ///\brief Returns this class name.
diff --git a/c++/src/H5DxferProp.cpp b/c++/src/H5DxferProp.cpp
index d9d7884..98e6214 100644
--- a/c++/src/H5DxferProp.cpp
+++ b/c++/src/H5DxferProp.cpp
@@ -306,7 +306,7 @@ DSetMemXferPropList::getDataTransform() const
 {
     // Initialize string to "", so that if there is no expression, the returned
     // string will be empty
-    H5std_string expression("");
+    H5std_string expression;
 
     // Preliminary call to get the expression's length
     ssize_t exp_len = H5Pget_data_transform(id, NULL, (size_t)0);
diff --git a/c++/src/H5Exception.cpp b/c++/src/H5Exception.cpp
index 1aa8ecc..8ea20ff 100644
--- a/c++/src/H5Exception.cpp
+++ b/c++/src/H5Exception.cpp
@@ -25,7 +25,7 @@ const char Exception::DEFAULT_MSG[] = "No detailed information provided";
 ///\brief       Default constructor.
 // Programmer   Binh-Minh Ribler - 2000
 //--------------------------------------------------------------------------
-Exception::Exception() : detail_message(""), func_name("") {}
+Exception::Exception() {}
 
 //--------------------------------------------------------------------------
 // Function:    Exception overloaded constructor
diff --git a/c++/src/H5File.cpp b/c++/src/H5File.cpp
index bbdcd6b..e40cafe 100644
--- a/c++/src/H5File.cpp
+++ b/c++/src/H5File.cpp
@@ -178,7 +178,7 @@ H5File::H5File(hid_t existing_id) : Group()
 ///\param       original - IN: H5File instance to copy
 // December 2000
 //--------------------------------------------------------------------------
-H5File::H5File(const H5File &original) : Group()
+H5File::H5File(const H5File &original) : Group(original)
 {
     id = original.getId();
     incRefCount(); // increment number of references to this id
diff --git a/c++/src/H5Location.cpp b/c++/src/H5Location.cpp
index 2d14bfc..b136faa 100644
--- a/c++/src/H5Location.cpp
+++ b/c++/src/H5Location.cpp
@@ -346,7 +346,7 @@ H5Location::getComment(const char *name, size_t buf_size) const
 {
     // Initialize string to "", so that if there is no comment, the returned
     // string will be empty
-    H5std_string comment("");
+    H5std_string comment;
 
     // Preliminary call to get the comment's length
     ssize_t comment_len = H5Oget_comment_by_name(getId(), name, NULL, (size_t)0, H5P_DEFAULT);
@@ -398,6 +398,7 @@ H5Location::getComment(const H5std_string &name, size_t buf_size) const
 {
     return (getComment(name.c_str(), buf_size));
 }
+
 #ifndef DOXYGEN_SHOULD_SKIP_THIS
 
 //--------------------------------------------------------------------------
@@ -646,6 +647,7 @@ H5Location::p_get_obj_type(void *ref, H5R_type_t ref_type) const
     return (obj_type);
 }
 #endif // DOXYGEN_SHOULD_SKIP_THIS
+
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 //--------------------------------------------------------------------------
@@ -704,6 +706,7 @@ H5Location::p_get_ref_obj_type(void *ref, H5R_type_t ref_type) const
     }
     return (obj_type);
 }
+#endif // DOXYGEN_SHOULD_SKIP_THIS
 
 //--------------------------------------------------------------------------
 // Function:    H5Location::getRegion
@@ -1816,7 +1819,7 @@ H5Location::getLinkval(const char *name, size_t size) const
     H5L_info2_t  linkinfo;
     char *       value_C; // value in C string
     size_t       val_size = size;
-    H5std_string value    = "";
+    H5std_string value;
     herr_t       ret_value;
 
     // if user doesn't provide buffer size, determine it
@@ -2294,7 +2297,6 @@ H5Location::childObjVersion(const H5std_string &objname) const
 }
 
 #ifndef H5_NO_DEPRECATED_SYMBOLS
-#ifndef DOXYGEN_SHOULD_SKIP_THIS
 //--------------------------------------------------------------------------
 // Function:    H5Location::getObjTypeByIdx
 ///\brief       Returns the type of an object in this group, given the
@@ -2372,7 +2374,6 @@ H5Location::getObjTypeByIdx(hsize_t idx, H5std_string &type_name) const
     return (obj_type);
 }
 
-#endif // DOXYGEN_SHOULD_SKIP_THIS
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 //--------------------------------------------------------------------------
@@ -2433,6 +2434,4 @@ f_DataSpace_setId(DataSpace *dspace, hid_t new_id)
 //--------------------------------------------------------------------------
 H5Location::~H5Location() {}
 
-#endif // DOXYGEN_SHOULD_SKIP_THIS
-
 } // namespace H5
diff --git a/c++/src/H5Object.cpp b/c++/src/H5Object.cpp
index 725d1da..c2eba8d 100644
--- a/c++/src/H5Object.cpp
+++ b/c++/src/H5Object.cpp
@@ -477,7 +477,7 @@ H5Object::getObjName(char *obj_name, size_t buf_size) const
 H5std_string
 H5Object::getObjName() const
 {
-    H5std_string obj_name(""); // object name to return
+    H5std_string obj_name; // object name to return
 
     // Preliminary call to get the size of the object name
     ssize_t name_size = H5Iget_name(getId(), NULL, static_cast<size_t>(0));
diff --git a/c++/test/dsets.cpp b/c++/test/dsets.cpp
index 93c266f..0faf457 100644
--- a/c++/test/dsets.cpp
+++ b/c++/test/dsets.cpp
@@ -1157,7 +1157,7 @@ const int          RANK1 = 1;
 const H5std_string FILE_ACCPLIST("test_accplist.h5");
 
 static herr_t
-test_chunk_cache(FileAccPropList fapl)
+test_chunk_cache(const FileAccPropList &fapl)
 {
     SUBTEST("DSetAccPropList::set/getChunkCache");
 
diff --git a/c++/test/h5cpputil.cpp b/c++/test/h5cpputil.cpp
index d42fc8c..38f9300 100644
--- a/c++/test/h5cpputil.cpp
+++ b/c++/test/h5cpputil.cpp
@@ -212,7 +212,7 @@ InvalidActionException::InvalidActionException() : Exception() {}
 //              func    - IN: Name of the function where failure should occur
 //              message - IN: Message
 //--------------------------------------------------------------------------
-InvalidActionException::InvalidActionException(const H5std_string func, const H5std_string message)
+InvalidActionException::InvalidActionException(const H5std_string &func, const H5std_string &message)
     : Exception(func, message)
 {
 }
@@ -237,7 +237,7 @@ TestFailedException::TestFailedException() : Exception() {}
 //              func    - IN: Name of the function where failure should occur
 //              message - IN: Message
 //--------------------------------------------------------------------------
-TestFailedException::TestFailedException(const H5std_string func, const H5std_string message)
+TestFailedException::TestFailedException(const H5std_string &func, const H5std_string &message)
     : Exception(func, message)
 {
 }
diff --git a/c++/test/h5cpputil.h b/c++/test/h5cpputil.h
index 4439ae3..444bc68 100644
--- a/c++/test/h5cpputil.h
+++ b/c++/test/h5cpputil.h
@@ -48,14 +48,14 @@ void issue_fail_msg(const char *where, int line, const char *file_name, const ch
 
 class InvalidActionException : public Exception {
   public:
-    InvalidActionException(const H5std_string func_name, const H5std_string message = DEFAULT_MSG);
+    InvalidActionException(const H5std_string &func_name, const H5std_string &message = DEFAULT_MSG);
     InvalidActionException();
     virtual ~InvalidActionException() throw();
 };
 
 class TestFailedException : public Exception {
   public:
-    TestFailedException(const H5std_string func_name, const H5std_string message = DEFAULT_MSG);
+    TestFailedException(const H5std_string &func_name, const H5std_string &message = DEFAULT_MSG);
     TestFailedException();
     virtual ~TestFailedException() throw();
 };
diff --git a/src/H5Tconv.c b/src/H5Tconv.c
index 60ad627..8cc6ede 100644
--- a/src/H5Tconv.c
+++ b/src/H5Tconv.c
@@ -8477,7 +8477,7 @@ H5T__conv_f_i(hid_t src_id, hid_t dst_id, H5T_cdata_t *cdata, size_t nelmts, siz
             /* Allocate enough space for the buffer holding temporary
              * converted value
              */
-            buf_size = (size_t)(HDpow((double)2.0f, (double)src.u.f.esize) / 8 + 1);
+            buf_size = (size_t)(HDpow(2.0, (double)src.u.f.esize) / 8 + 1);
             int_buf  = (uint8_t *)H5MM_calloc(buf_size);
 
             /* Get conversion exception callback property */
@@ -9315,7 +9315,7 @@ H5T__conv_i_f(hid_t src_id, hid_t dst_id, H5T_cdata_t *cdata, size_t nelmts, siz
                 }
 
                 /* Check if the exponent is too big */
-                expo_max = (hsize_t)(HDpow((double)2.0f, (double)dst.u.f.esize) - 1);
+                expo_max = (hsize_t)(HDpow(2.0, (double)dst.u.f.esize) - 1);
 
                 if (expo > expo_max) {    /*overflows*/
                     if (cb_struct.func) { /*user's exception handler.  Reverse back source order*/
diff --git a/src/H5Zscaleoffset.c b/src/H5Zscaleoffset.c
index 3a08a07..5310f7d 100644
--- a/src/H5Zscaleoffset.c
+++ b/src/H5Zscaleoffset.c
@@ -364,12 +364,12 @@ H5Z_class2_t H5Z_SCALEOFFSET[1] = {{
 #define H5Z_scaleoffset_max_min_3(i, d_nelmts, buf, filval, max, min, D_val)                                 \
     {                                                                                                        \
         i = 0;                                                                                               \
-        while (i < d_nelmts && HDfabs(buf[i] - filval) < HDpow(10.0f, -D_val))                               \
+        while (i < d_nelmts && HDfabs(buf[i] - filval) < HDpow(10.0, -D_val))                                \
             i++;                                                                                             \
         if (i < d_nelmts)                                                                                    \
             min = max = buf[i];                                                                              \
         for (; i < d_nelmts; i++) {                                                                          \
-            if (HDfabs(buf[i] - filval) < HDpow(10.0f, -D_val))                                              \
+            if (HDfabs(buf[i] - filval) < HDpow(10.0, -D_val))                                               \
                 continue; /* ignore fill value */                                                            \
             if (buf[i] > max)                                                                                \
                 max = buf[i];                                                                                \
diff --git a/test/cache_common.c b/test/cache_common.c
index 54b1cc5..676b8d1 100644
--- a/test/cache_common.c
+++ b/test/cache_common.c
@@ -1683,7 +1683,7 @@ execute_flush_op(H5F_t *file_ptr, struct test_entry_t *entry_ptr, struct flush_o
     HDassert(cache_ptr != NULL);
     HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
     HDassert(entry_ptr != NULL);
-    HDassert(entry_ptr = entry_ptr->self);
+    HDassert(entry_ptr == entry_ptr->self);
     HDassert(entry_ptr->header.addr == entry_ptr->addr);
     HDassert((entry_ptr->flush_op_self_resize_in_progress) || (entry_ptr->header.size == entry_ptr->size));
     HDassert(op_ptr != NULL);
@@ -2243,7 +2243,7 @@ resize_entry(H5F_t *file_ptr, int32_t type, int32_t idx, size_t new_size, hbool_
                     }
                     else {
 
-                        HDassert(entry_ptr->size = (entry_ptr->header).size);
+                        HDassert(entry_ptr->size == (entry_ptr->header).size);
                     }
                 }
             }
diff --git a/test/dsets.c b/test/dsets.c
index 8600d75..0905b4e 100644
--- a/test/dsets.c
+++ b/test/dsets.c
@@ -3181,7 +3181,7 @@ test_nbit_int(hid_t file)
     /* Initialize data, assuming size of long long >= size of int */
     for (i = 0; i < (size_t)size[0]; i++)
         for (j = 0; j < (size_t)size[1]; j++) {
-            power           = HDpow(2.0f, (double)(precision - 1));
+            power           = HDpow(2.0, (double)(precision - 1));
             orig_data[i][j] = (int)(((long long)HDrandom() % (long long)power) << offset);
 
             /* even-numbered values are negtive */
@@ -3558,7 +3558,7 @@ test_nbit_array(hid_t file)
         for (j = 0; j < (size_t)size[1]; j++)
             for (m = 0; m < (size_t)adims[0]; m++)
                 for (n = 0; n < (size_t)adims[1]; n++) {
-                    power = HDpow(2.0F, (double)precision);
+                    power = HDpow(2.0, (double)precision);
                     orig_data[i][j][m][n] =
                         (unsigned int)(((long long)HDrandom() % (long long)power) << offset);
                 } /* end for */
@@ -3754,11 +3754,11 @@ test_nbit_compound(hid_t file)
     /* Initialize data, assuming size of long long >= size of member datatypes */
     for (i = 0; i < (size_t)size[0]; i++)
         for (j = 0; j < (size_t)size[1]; j++) {
-            power             = HDpow(2.0F, (double)(precision[0] - 1));
+            power             = HDpow(2.0, (double)(precision[0] - 1));
             orig_data[i][j].i = (int)(((long long)HDrandom() % (long long)power) << offset[0]);
-            power             = HDpow(2.0F, (double)(precision[1] - 1));
+            power             = HDpow(2.0, (double)(precision[1] - 1));
             orig_data[i][j].c = (char)(((long long)HDrandom() % (long long)power) << offset[1]);
-            power             = HDpow(2.0F, (double)(precision[2] - 1));
+            power             = HDpow(2.0, (double)(precision[2] - 1));
             orig_data[i][j].s = (short)(((long long)HDrandom() % (long long)power) << offset[2]);
             orig_data[i][j].f = float_val[i][j];
 
@@ -4036,32 +4036,32 @@ test_nbit_compound_2(hid_t file)
     /* Initialize data, assuming size of long long >= size of member datatypes */
     for (i = 0; i < (size_t)size[0]; i++)
         for (j = 0; j < (size_t)size[1]; j++) {
-            power               = HDpow(2.0F, (double)(precision[0] - 1));
+            power               = HDpow(2.0, (double)(precision[0] - 1));
             orig_data[i][j].a.i = (int)(((long long)HDrandom() % (long long)power) << offset[0]);
-            power               = HDpow(2.0F, (double)(precision[1] - 1));
+            power               = HDpow(2.0, (double)(precision[1] - 1));
             orig_data[i][j].a.c = (char)(((long long)HDrandom() % (long long)power) << offset[1]);
-            power               = HDpow(2.0F, (double)(precision[2] - 1));
+            power               = HDpow(2.0, (double)(precision[2] - 1));
             orig_data[i][j].a.s = (short)(-(((long long)HDrandom() % (long long)power) << offset[2]));
             orig_data[i][j].a.f = float_val[i][j];
 
-            power             = HDpow(2.0F, (double)precision[3]);
+            power             = HDpow(2.0, (double)precision[3]);
             orig_data[i][j].v = (unsigned int)(((long long)HDrandom() % (long long)power) << offset[3]);
 
             for (m = 0; m < (size_t)array_dims[0]; m++)
                 for (n = 0; n < (size_t)array_dims[1]; n++) {
-                    power                   = HDpow(2.0F, (double)(precision[4] - 1));
+                    power                   = HDpow(2.0, (double)(precision[4] - 1));
                     orig_data[i][j].b[m][n] = (char)(((long long)HDrandom() % (long long)power) << offset[4]);
                 } /* end for */
 
             for (m = 0; m < (size_t)array_dims[0]; m++)
                 for (n = 0; n < (size_t)array_dims[1]; n++) {
-                    power = HDpow(2.0F, (double)(precision[0] - 1));
+                    power = HDpow(2.0, (double)(precision[0] - 1));
                     orig_data[i][j].d[m][n].i =
                         (int)(-(((long long)HDrandom() % (long long)power) << offset[0]));
-                    power = HDpow(2.0F, (double)(precision[1] - 1));
+                    power = HDpow(2.0, (double)(precision[1] - 1));
                     orig_data[i][j].d[m][n].c =
                         (char)(((long long)HDrandom() % (long long)power) << offset[1]);
-                    power = HDpow(2.0F, (double)(precision[2] - 1));
+                    power = HDpow(2.0, (double)(precision[2] - 1));
                     orig_data[i][j].d[m][n].s =
                         (short)(((long long)HDrandom() % (long long)power) << offset[2]);
                     orig_data[i][j].d[m][n].f = float_val[i][j];
@@ -4292,7 +4292,7 @@ test_nbit_compound_3(hid_t file)
 
     /* Initialize data */
     for (i = 0; i < (size_t)size[0]; i++) {
-        power = HDpow(2.0F, 17.0F - 1.0F);
+        power = HDpow(2.0, 17.0 - 1.0);
         HDmemset(&orig_data[i], 0, sizeof(orig_data[i]));
         orig_data[i].i = (int)(HDrandom() % (long)power);
         HDstrcpy(orig_data[i].str, "fixed-length C string");
@@ -4481,7 +4481,7 @@ test_nbit_int_size(hid_t file)
      */
     for (i = 0; i < DSET_DIM1; i++)
         for (j = 0; j < DSET_DIM2; j++) {
-            power      = HDpow(2.0F, (double)(precision - 1));
+            power      = HDpow(2.0, (double)(precision - 1));
             orig[i][j] = HDrandom() % (int)power << offset;
         }
 
@@ -5145,7 +5145,7 @@ test_scaleoffset_float(hid_t file)
     /* Check that the values read are the same as the values written */
     for (i = 0; i < (size_t)size[0]; i++) {
         for (j = 0; j < (size_t)size[1]; j++) {
-            if (HDfabs(new_data[i][j] - orig_data[i][j]) > HDpow(10.0F, -3.0F)) {
+            if (HDfabs(new_data[i][j] - orig_data[i][j]) > HDpow(10.0, -3.0)) {
                 H5_FAILED();
                 HDprintf("    Read different values than written.\n");
                 HDprintf("    At index %lu,%lu\n", (unsigned long)i, (unsigned long)j);
@@ -5291,7 +5291,7 @@ test_scaleoffset_float_2(hid_t file)
 
     /* Check that the values read are the same as the values written */
     for (j = 0; j < (size_t)size[1]; j++) {
-        if (HDfabs(new_data[0][j] - orig_data[0][j]) > HDpow(10.0F, -3.0F)) {
+        if (HDfabs(new_data[0][j] - orig_data[0][j]) > HDpow(10.0, -3.0)) {
             H5_FAILED();
             HDprintf("    Read different values than written.\n");
             HDprintf("    At index %lu,%lu\n", (unsigned long)0, (unsigned long)j);
@@ -5412,7 +5412,7 @@ test_scaleoffset_double(hid_t file)
     /* Check that the values read are the same as the values written */
     for (i = 0; i < (size_t)size[0]; i++) {
         for (j = 0; j < (size_t)size[1]; j++) {
-            if (HDfabs(new_data[i][j] - orig_data[i][j]) > HDpow(10.0F, -7.0F)) {
+            if (HDfabs(new_data[i][j] - orig_data[i][j]) > HDpow(10.0, -7.0)) {
                 H5_FAILED();
                 HDprintf("    Read different values than written.\n");
                 HDprintf("    At index %lu,%lu\n", (unsigned long)i, (unsigned long)j);
@@ -5558,7 +5558,7 @@ test_scaleoffset_double_2(hid_t file)
 
     /* Check that the values read are the same as the values written */
     for (j = 0; j < (size_t)size[1]; j++) {
-        if (HDfabs(new_data[0][j] - orig_data[0][j]) > HDpow(10.0F, -7.0F)) {
+        if (HDfabs(new_data[0][j] - orig_data[0][j]) > HDpow(10.0, -7.0)) {
             H5_FAILED();
             HDprintf("    Read different values than written.\n");
             HDprintf("    At index %lu,%lu\n", (unsigned long)0, (unsigned long)j);
diff --git a/test/earray.c b/test/earray.c
index 52908a7..bfd3d55 100644
--- a/test/earray.c
+++ b/test/earray.c
@@ -122,7 +122,7 @@ typedef struct earray_iter_t {
                   hsize_t cnt);             /* Initialize/allocate iterator private info */
     hssize_t (*next)(void *info);           /* Get the next element to test */
     hssize_t (*max_elem)(const void *info); /* Get the max. element set */
-    int (*state)(void *_eiter, const H5EA_create_t *cparam, const earray_test_param_t *tparam,
+    int (*state)(void *in_eiter, const H5EA_create_t *cparam, const earray_test_param_t *tparam,
                  earray_state_t *state, hsize_t idx); /* Get the state of the extensible array */
     herr_t (*term)(void *info);                       /* Shutdown/free iterator private info */
 } earray_iter_t;
@@ -1290,9 +1290,9 @@ eiter_fw_init(const H5EA_create_t H5_ATTR_UNUSED *cparam, const earray_test_para
  *-------------------------------------------------------------------------
  */
 static hssize_t
-eiter_fw_next(void *_eiter)
+eiter_fw_next(void *in_eiter)
 {
-    eiter_fw_t *eiter = (eiter_fw_t *)_eiter;
+    eiter_fw_t *eiter = (eiter_fw_t *)in_eiter;
     hssize_t    ret_val;
 
     /* Sanity check */
@@ -1318,9 +1318,9 @@ eiter_fw_next(void *_eiter)
  *-------------------------------------------------------------------------
  */
 static H5_ATTR_PURE hssize_t
-eiter_fw_max(const void *_eiter)
+eiter_fw_max(const void *in_eiter)
 {
-    const eiter_fw_t *eiter = (const eiter_fw_t *)_eiter;
+    const eiter_fw_t *eiter = (const eiter_fw_t *)in_eiter;
 
     /* Sanity check */
     HDassert(eiter);
@@ -1343,10 +1343,10 @@ eiter_fw_max(const void *_eiter)
  *-------------------------------------------------------------------------
  */
 static int
-eiter_fw_state(void *_eiter, const H5EA_create_t *cparam, const earray_test_param_t *tparam,
+eiter_fw_state(void *in_eiter, const H5EA_create_t *cparam, const earray_test_param_t *tparam,
                earray_state_t *state, hsize_t idx)
 {
-    eiter_fw_t *eiter = (eiter_fw_t *)_eiter;
+    eiter_fw_t *eiter = (eiter_fw_t *)in_eiter;
 
     /* Sanity check */
     HDassert(eiter);
@@ -1490,9 +1490,9 @@ eiter_rv_init(const H5EA_create_t *cparam, const earray_test_param_t *tparam, hs
  *-------------------------------------------------------------------------
  */
 static hssize_t
-eiter_rv_next(void *_eiter)
+eiter_rv_next(void *in_eiter)
 {
-    eiter_rv_t *eiter = (eiter_rv_t *)_eiter;
+    eiter_rv_t *eiter = (eiter_rv_t *)in_eiter;
     hssize_t    ret_val;
 
     /* Sanity check */
@@ -1518,9 +1518,9 @@ eiter_rv_next(void *_eiter)
  *-------------------------------------------------------------------------
  */
 static H5_ATTR_PURE hssize_t
-eiter_rv_max(const void *_eiter)
+eiter_rv_max(const void *in_eiter)
 {
-    const eiter_rv_t *eiter = (const eiter_rv_t *)_eiter;
+    const eiter_rv_t *eiter = (const eiter_rv_t *)in_eiter;
 
     /* Sanity check */
     HDassert(eiter);
@@ -1543,10 +1543,10 @@ eiter_rv_max(const void *_eiter)
  *-------------------------------------------------------------------------
  */
 static int
-eiter_rv_state(void *_eiter, const H5EA_create_t *cparam, const earray_test_param_t *tparam,
+eiter_rv_state(void *in_eiter, const H5EA_create_t *cparam, const earray_test_param_t *tparam,
                earray_state_t *state, hsize_t idx)
 {
-    eiter_rv_t *eiter = (eiter_rv_t *)_eiter;
+    eiter_rv_t *eiter = (eiter_rv_t *)in_eiter;
 
     /* Sanity check */
     HDassert(eiter);
@@ -1720,9 +1720,9 @@ eiter_rnd_init(const H5EA_create_t H5_ATTR_UNUSED *cparam, const earray_test_par
  *-------------------------------------------------------------------------
  */
 static hssize_t
-eiter_rnd_next(void *_eiter)
+eiter_rnd_next(void *in_eiter)
 {
-    eiter_rnd_t *eiter = (eiter_rnd_t *)_eiter;
+    eiter_rnd_t *eiter = (eiter_rnd_t *)in_eiter;
     hssize_t     ret_val;
 
     /* Sanity check */
@@ -1753,9 +1753,9 @@ eiter_rnd_next(void *_eiter)
  *-------------------------------------------------------------------------
  */
 static H5_ATTR_PURE hssize_t
-eiter_rnd_max(const void *_eiter)
+eiter_rnd_max(const void *in_eiter)
 {
-    const eiter_rnd_t *eiter = (const eiter_rnd_t *)_eiter;
+    const eiter_rnd_t *eiter = (const eiter_rnd_t *)in_eiter;
 
     /* Sanity check */
     HDassert(eiter);
@@ -1778,9 +1778,9 @@ eiter_rnd_max(const void *_eiter)
  *-------------------------------------------------------------------------
  */
 static int
-eiter_rnd_term(void *_eiter)
+eiter_rnd_term(void *in_eiter)
 {
-    eiter_rnd_t *eiter = (eiter_rnd_t *)_eiter;
+    eiter_rnd_t *eiter = (eiter_rnd_t *)in_eiter;
 
     /* Sanity check */
     HDassert(eiter);
@@ -1934,9 +1934,9 @@ eiter_cyc_init(const H5EA_create_t H5_ATTR_UNUSED *cparam, const earray_test_par
  *-------------------------------------------------------------------------
  */
 static hssize_t
-eiter_cyc_next(void *_eiter)
+eiter_cyc_next(void *in_eiter)
 {
-    eiter_cyc_t *eiter = (eiter_cyc_t *)_eiter;
+    eiter_cyc_t *eiter = (eiter_cyc_t *)in_eiter;
     hssize_t     ret_val;
 
     /* Sanity check */
@@ -1969,9 +1969,9 @@ eiter_cyc_next(void *_eiter)
  *-------------------------------------------------------------------------
  */
 static H5_ATTR_PURE hssize_t
-eiter_cyc_max(const void *_eiter)
+eiter_cyc_max(const void *in_eiter)
 {
-    const eiter_cyc_t *eiter = (const eiter_cyc_t *)_eiter;
+    const eiter_cyc_t *eiter = (const eiter_cyc_t *)in_eiter;
 
     /* Sanity check */
     HDassert(eiter);
@@ -1994,9 +1994,9 @@ eiter_cyc_max(const void *_eiter)
  *-------------------------------------------------------------------------
  */
 static int
-eiter_cyc_term(void *_eiter)
+eiter_cyc_term(void *in_eiter)
 {
-    eiter_cyc_t *eiter = (eiter_cyc_t *)_eiter;
+    eiter_cyc_t *eiter = (eiter_cyc_t *)in_eiter;
 
     /* Sanity check */
     HDassert(eiter);
diff --git a/test/error_test.c b/test/error_test.c
index e294a43..9bbebec 100644
--- a/test/error_test.c
+++ b/test/error_test.c
@@ -129,13 +129,8 @@ test_error(hid_t file)
         TEST_ERROR;
     if (old_data != NULL)
         TEST_ERROR;
-#ifdef H5_USE_16_API
-    if (old_func != (H5E_auto_t)H5Eprint)
-        TEST_ERROR;
-#else  /* H5_USE_16_API */
     if (old_func != (H5E_auto2_t)H5Eprint2)
         TEST_ERROR;
-#endif /* H5_USE_16_API */
 
     if (H5Eset_auto2(H5E_DEFAULT, NULL, NULL) < 0)
         TEST_ERROR;
diff --git a/test/external.c b/test/external.c
index 9109e75..0957a03 100644
--- a/test/external.c
+++ b/test/external.c
@@ -465,7 +465,7 @@ error:
  *-------------------------------------------------------------------------
  */
 static int
-__add_external_files(hid_t dcpl_id, unsigned int n_external_files, off_t offset, hsize_t max_ext_size)
+add_external_files(hid_t dcpl_id, unsigned int n_external_files, off_t offset, hsize_t max_ext_size)
 {
     char         exname[AEF_EXNAME_MAX_LEN + 1];
     unsigned int i = 0;
@@ -519,7 +519,7 @@ test_multiple_files(hid_t file)
 
     max_ext_size = (hsize_t)(sizeof(int) * max_size[0] / n_external_files);
 
-    if (__add_external_files(dcpl, n_external_files, 0, max_ext_size) < 0) {
+    if (add_external_files(dcpl, n_external_files, 0, max_ext_size) < 0) {
         FAIL_STACK_ERROR;
     }
 
@@ -543,7 +543,7 @@ test_multiple_files(hid_t file)
 
     max_ext_size -= 1;
 
-    if (__add_external_files(dcpl, n_external_files, 0, max_ext_size) < 0) {
+    if (add_external_files(dcpl, n_external_files, 0, max_ext_size) < 0) {
         FAIL_STACK_ERROR;
     }
 
diff --git a/test/ohdr.c b/test/ohdr.c
index 54040e1..c586ff3 100644
--- a/test/ohdr.c
+++ b/test/ohdr.c
@@ -780,7 +780,7 @@ count_attributes(hid_t dset_id)
  * On success, stores size in `size_out` pointer.
  */
 static herr_t
-_oh_getsize(hid_t did, hsize_t *size_out)
+oh_getsize(hid_t did, hsize_t *size_out)
 {
     H5O_native_info_t ninfo;
 
@@ -803,9 +803,9 @@ oh_compare(hid_t did1, hid_t did2)
     hsize_t space1 = 0;
     hsize_t space2 = 0;
 
-    if (FAIL == _oh_getsize(did1, &space1))
+    if (FAIL == oh_getsize(did1, &space1))
         return -1;
-    if (FAIL == _oh_getsize(did2, &space2))
+    if (FAIL == oh_getsize(did2, &space2))
         return -2;
 
     if (space1 < space2)
diff --git a/tools/test/h5diff/h5diffgentest.c b/tools/test/h5diff/h5diffgentest.c
index cf60a6a..f03254e 100644
--- a/tools/test/h5diff/h5diffgentest.c
+++ b/tools/test/h5diff/h5diffgentest.c
@@ -465,15 +465,15 @@ test_basic(const char *fname1, const char *fname2, const char *fname3)
         float data15[6];
         float data16[6];
 
-        data15[0] = (float)HDsqrt(-1.0F);
+        data15[0] = (float)HDsqrt(-1.0);
         data15[1] = 1.0F;
-        data15[2] = (float)HDsqrt(-1.0F);
+        data15[2] = (float)HDsqrt(-1.0);
         data15[3] = 1.0F;
         data15[4] = 1.0F;
         data15[5] = 1.0F;
 
-        data16[0] = (float)HDsqrt(-1.0F);
-        data16[1] = (float)HDsqrt(-1.0F);
+        data16[0] = (float)HDsqrt(-1.0);
+        data16[1] = (float)HDsqrt(-1.0);
         data16[2] = 1.0F;
         data16[3] = 1.0F;
         data16[4] = 1.0F;
@@ -492,19 +492,19 @@ test_basic(const char *fname1, const char *fname2, const char *fname3)
         double data17[6];
         double data18[6];
 
-        data17[0] = HDsqrt(-1.0F);
-        data17[1] = 1.0F;
-        data17[2] = HDsqrt(-1.0F);
-        data17[3] = 1.0F;
-        data17[4] = 1.0F;
-        data17[5] = 1.0F;
+        data17[0] = HDsqrt(-1.0);
+        data17[1] = 1.0;
+        data17[2] = HDsqrt(-1.0);
+        data17[3] = 1.0;
+        data17[4] = 1.0;
+        data17[5] = 1.0;
 
-        data18[0] = HDsqrt(-1.0F);
-        data18[1] = HDsqrt(-10000.0F);
-        data18[2] = 1.0F;
-        data18[3] = 1.0F;
-        data18[4] = 1.0F;
-        data18[5] = 1.0F;
+        data18[0] = HDsqrt(-1.0);
+        data18[1] = HDsqrt(-10000.0);
+        data18[2] = 1.0;
+        data18[3] = 1.0;
+        data18[4] = 1.0;
+        data18[5] = 1.0;
 
         write_dset(gid1, 1, dims1, "fp17", H5T_NATIVE_DOUBLE, data17);
         write_dset(gid1, 1, dims1, "fp18", H5T_NATIVE_DOUBLE, data18);
@@ -519,11 +519,11 @@ test_basic(const char *fname1, const char *fname2, const char *fname3)
         float  data19[6];
         double data20[6];
 
-        data19[0] = data19[1] = data19[2] = (float)HDlog(0.0F);
-        data19[3] = data19[4] = data19[5] = (float)-HDlog(0.0F);
+        data19[0] = data19[1] = data19[2] = (float)HDlog(0.0);
+        data19[3] = data19[4] = data19[5] = (float)-HDlog(0.0);
 
-        data20[0] = data20[1] = data20[2] = HDlog(0.0F);
-        data20[3] = data20[4] = data20[5] = -HDlog(0.0F);
+        data20[0] = data20[1] = data20[2] = HDlog(0.0);
+        data20[3] = data20[4] = data20[5] = -HDlog(0.0);
 
         write_dset(gid1, 1, dims1, "fp19", H5T_NATIVE_FLOAT, data19);
         write_dset(gid1, 1, dims1, "fp19_COPY", H5T_NATIVE_FLOAT, data19);
@@ -547,13 +547,13 @@ test_basic(const char *fname1, const char *fname2, const char *fname3)
         size_t  type_size;
         hid_t   tid;
 
-        buf1[0].d = HDsqrt(-1.0F);
-        buf1[0].f = (float)HDsqrt(-1.0F);
-        buf2[0].d = HDsqrt(-1.0F);
-        buf2[0].f = (float)HDsqrt(-1.0F);
+        buf1[0].d = HDsqrt(-1.0);
+        buf1[0].f = (float)HDsqrt(-1.0);
+        buf2[0].d = HDsqrt(-1.0);
+        buf2[0].f = (float)HDsqrt(-1.0);
 
-        buf1[1].d = HDsqrt(-1.0F);
-        buf1[1].f = (float)HDsqrt(-1.0F);
+        buf1[1].d = HDsqrt(-1.0);
+        buf1[1].f = (float)HDsqrt(-1.0);
         buf2[1].d = 0.0F;
         buf2[1].f = 0.0F;
 
diff --git a/tools/test/h5repack/h5repackgentest.c b/tools/test/h5repack/h5repackgentest.c
index 2b94422..576b1c7 100644
--- a/tools/test/h5repack/h5repackgentest.c
+++ b/tools/test/h5repack/h5repackgentest.c
@@ -72,8 +72,8 @@ struct external_def {
  * Returns 0 on success, -1 on failure.
  */
 static int
-__make_dataset(hid_t file_id, const char *dset_name, hid_t mem_type_id, hid_t space_id, hid_t dcpl_id,
-               void *wdata)
+make_dataset(hid_t file_id, const char *dset_name, hid_t mem_type_id, hid_t space_id, hid_t dcpl_id,
+             void *wdata)
 {
     hid_t dset_id   = H5I_INVALID_HID;
     int   ret_value = 0;
@@ -90,7 +90,7 @@ done:
         (void)H5Dclose(dset_id);
 
     return ret_value;
-} /* end __make_dataset() */
+} /* end make_dataset() */
 
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  * Helper function to populate the DCPL external storage list.
@@ -101,8 +101,8 @@ done:
  * Returns 0 on success, -1 on failure.
  */
 static int
-__set_dcpl_external_list(hid_t dcpl, const char *filename, unsigned n_elts_per_file, unsigned n_elts_total,
-                         hsize_t elt_size)
+set_dcpl_external_list(hid_t dcpl, const char *filename, unsigned n_elts_per_file, unsigned n_elts_total,
+                       hsize_t elt_size)
 {
     char     name[MAX_NAME_SIZE];
     unsigned n_external_files = 0;
@@ -123,7 +123,7 @@ __set_dcpl_external_list(hid_t dcpl, const char *filename, unsigned n_elts_per_f
             return -1;
     }
     return 0;
-} /* end __set_dcpl_external_list() */
+} /* end set_dcpl_external_list() */
 
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  * Generalized utility function to write a file with the specified data and
@@ -132,8 +132,8 @@ __set_dcpl_external_list(hid_t dcpl, const char *filename, unsigned n_elts_per_f
  * Returns 0 on success, -1 on failure.
  */
 static int
-__make_file(const char *basename, struct external_def *ext, hid_t type_id, hsize_t rank, hsize_t *dims,
-            void *wdata)
+make_file(const char *basename, struct external_def *ext, hid_t type_id, hsize_t rank, hsize_t *dims,
+          void *wdata)
 {
     char  filename[MAX_NAME_SIZE];
     hid_t file_id   = H5I_INVALID_HID;
@@ -149,8 +149,8 @@ __make_file(const char *basename, struct external_def *ext, hid_t type_id, hsize
         if (dcpl_id == H5I_INVALID_HID)
             H5REPACKGENTEST_OOPS;
 
-        if (__set_dcpl_external_list(dcpl_id, basename, ext->n_elts_per_file, ext->n_elts_total,
-                                     ext->type_size) < 0)
+        if (set_dcpl_external_list(dcpl_id, basename, ext->n_elts_per_file, ext->n_elts_total,
+                                   ext->type_size) < 0)
             H5REPACKGENTEST_OOPS;
     }
 
@@ -162,13 +162,13 @@ __make_file(const char *basename, struct external_def *ext, hid_t type_id, hsize
     if (file_id == H5I_INVALID_HID)
         H5REPACKGENTEST_OOPS;
 
-    if (__make_dataset(file_id, "dset", type_id, space_id, dcpl_id, wdata) < 0)
+    if (make_dataset(file_id, "dset", type_id, space_id, dcpl_id, wdata) < 0)
         H5REPACKGENTEST_OOPS;
 
 done:
     H5REPACKGENTEST_COMMON_CLEANUP(dcpl_id, file_id, space_id);
     return ret_value;
-} /* end __make_file() */
+} /* end make_file() */
 
 /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  * Returns 0 on success, -1 on failure.
@@ -190,7 +190,7 @@ generate_int32le_1d(hbool_t external)
     }
 
     def_ptr = (TRUE == external) ? (&def) : NULL;
-    if (__make_file(FILE_INT32LE_1, def_ptr, H5T_STD_I32LE, 1, dims, wdata) < 0)
+    if (make_file(FILE_INT32LE_1, def_ptr, H5T_STD_I32LE, 1, dims, wdata) < 0)
         ret_value = -1;
 
     return ret_value;
@@ -216,7 +216,7 @@ generate_int32le_2d(hbool_t external)
     }
 
     def_ptr = (TRUE == external) ? (&def) : NULL;
-    if (__make_file(FILE_INT32LE_2, def_ptr, H5T_STD_I32LE, 2, dims, wdata) < 0)
+    if (make_file(FILE_INT32LE_2, def_ptr, H5T_STD_I32LE, 2, dims, wdata) < 0)
         ret_value = -1;
 
     return ret_value;
@@ -249,7 +249,7 @@ generate_int32le_3d(hbool_t external)
     }
 
     def_ptr = (TRUE == external) ? (&def) : NULL;
-    if (__make_file(FILE_INT32LE_3, def_ptr, H5T_STD_I32LE, 3, dims, wdata) < 0)
+    if (make_file(FILE_INT32LE_3, def_ptr, H5T_STD_I32LE, 3, dims, wdata) < 0)
         ret_value = -1;
 
     return ret_value;
@@ -282,7 +282,7 @@ generate_uint8be(hbool_t external)
     }
 
     def_ptr = (TRUE == external) ? (&def) : NULL;
-    if (__make_file(FILE_UINT8BE, def_ptr, H5T_STD_U8BE, 3, dims, wdata) < 0)
+    if (make_file(FILE_UINT8BE, def_ptr, H5T_STD_U8BE, 3, dims, wdata) < 0)
         ret_value = -1;
 
     return ret_value;
@@ -312,7 +312,7 @@ generate_f32le(hbool_t external)
     }
 
     def_ptr = (TRUE == external) ? (&def) : NULL;
-    if (__make_file(FILE_F32LE, def_ptr, H5T_IEEE_F32LE, 2, dims, wdata) < 0)
+    if (make_file(FILE_F32LE, def_ptr, H5T_IEEE_F32LE, 2, dims, wdata) < 0)
         ret_value = -1;
 
     return ret_value;
diff --git a/tools/test/perform/sio_engine.c b/tools/test/perform/sio_engine.c
index f8061d4..e5a0ec8 100644
--- a/tools/test/perform/sio_engine.c
+++ b/tools/test/perform/sio_engine.c
@@ -80,7 +80,7 @@ static int clean_file_g = -1; /*whether to cleanup temporary test     */
 /*0 is no cleanup; 1 is do cleanup      */
 
 /* the different types of file descriptors we can expect */
-typedef union _file_descr {
+typedef union {
     int   posixfd; /* POSIX file handle*/
     hid_t h5fd;    /* HDF5 file        */
 } file_descr;
diff --git a/tools/test/perform/sio_perf.c b/tools/test/perform/sio_perf.c
index 8463ffa..5b3a9e8 100644
--- a/tools/test/perform/sio_perf.c
+++ b/tools/test/perform/sio_perf.c
@@ -292,7 +292,7 @@ struct options {
     size_t      page_size;
 };
 
-typedef struct _minmax {
+typedef struct {
     double min;
     double max;
     double sum;