diff --git a/modules/c++/CMakeLists.txt b/modules/c++/CMakeLists.txt
index 3cd8d662a0..7ca6fdffa3 100644
--- a/modules/c++/CMakeLists.txt
+++ b/modules/c++/CMakeLists.txt
@@ -2,15 +2,9 @@ set(TARGET_LANGUAGE c++)
 
 # turn on warnings as errors
 if (MSVC)
-    add_compile_options(/WX /W4)
+    add_compile_options(/WX /W4) # /Wall
 elseif (UNIX)
-    # still building with older GCC :-(
-    #add_compile_options(-Werror)
-    add_compile_options(-Wall)
-    #add_compile_options(-Wpedantic -Wextra)
-    add_compile_options(-Wno-deprecated-copy)
-    add_compile_options(-Wno-expansion-to-defined -Wno-type-limits)
-    add_compile_options(-Wno-unused-parameter)
+    add_compile_options(-Werror -Wall -Wpedantic -Wextra)
 endif()
 
 # add an interface library for unittests
diff --git a/modules/c++/config/include/config/disable_compiler_warnings.h b/modules/c++/config/include/config/disable_compiler_warnings.h
new file mode 100644
index 0000000000..a87d281089
--- /dev/null
+++ b/modules/c++/config/include/config/disable_compiler_warnings.h
@@ -0,0 +1,43 @@
+/* =========================================================================
+ * This file is part of config-c++
+ * =========================================================================
+ *
+ * (C) Copyright 2023, Maxar Technologies, Inc.
+ *
+ * config-c++ is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program; If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ */
+#ifndef CODA_OSS_config_disable_compiler_warnings_h_INCLUDED_
+#define CODA_OSS_config_disable_compiler_warnings_h_INCLUDED_
+#pragma once
+
+#include "compiler_extensions.h"
+
+#if _MSC_VER
+// We don't care about any padding added to structs
+#pragma warning(disable: 4820) //  '...': '...' bytes padding added after data member '...'
+
+// Assume any unreferenced functions will be used in other code
+#pragma warning(disable: 4514) // '...': unreferenced inline function has been removed
+
+// ???
+#pragma warning(disable: 4668) // '...' is not defined as a preprocessor macro, replacing with '...' for '...'
+
+// ???
+#pragma warning(disable: 5045) // Compiler will insert Spectre mitigation for memory load if /Qspectre switch specified
+
+#endif // _MSC_VER
+
+#endif  // CODA_OSS_config_disable_compiler_warnings_h_INCLUDED_
diff --git a/modules/c++/except/include/except/Context.h b/modules/c++/except/include/except/Context.h
index cef7af1763..83f80acee3 100644
--- a/modules/c++/except/include/except/Context.h
+++ b/modules/c++/except/include/except/Context.h
@@ -29,6 +29,7 @@
 #include <ostream>
 
 #include "config/Exports.h"
+#include "config/disable_compiler_warnings.h"
 
 /*!
  * \file
diff --git a/modules/c++/except/include/except/Error.h b/modules/c++/except/include/except/Error.h
index 76823bfe49..56fcdb78ca 100644
--- a/modules/c++/except/include/except/Error.h
+++ b/modules/c++/except/include/except/Error.h
@@ -46,13 +46,13 @@
       _Name##Error_(const except::Throwable& t, const except::Context& c) : _Base(t, c){} \
       _Name##Error_(const except::ThrowableEx& t, const except::Context& c) : _Base(t, c){} \
       std::string getType() const noexcept override { return #_Name; } \
-  };
+  }
 #define DECLARE_EXTENDED_ERROR(_Name, _Base) DECLARE_EXTENDED_ERROR_(_Name, Error, _Base)
 #define DECLARE_EXTENDED_ERROREX(_Name, _Base) DECLARE_EXTENDED_ERROR_(_Name, ErrorEx, _Base)
 
 // Need to keep this around for existing code
 #define DECLARE_ERROR(_Name) \
-    DECLARE_EXTENDED_ERROR(_Name, except::Error); \
+    DECLARE_EXTENDED_ERROR(_Name, except::Error);		\
     DECLARE_EXTENDED_ERROREX(_Name, except::ErrorEx)
 
 namespace except
diff --git a/modules/c++/except/include/except/Exception.h b/modules/c++/except/include/except/Exception.h
index 12cedcc07c..33a8563632 100644
--- a/modules/c++/except/include/except/Exception.h
+++ b/modules/c++/except/include/except/Exception.h
@@ -63,7 +63,7 @@
       _Name##Exception_(const except::ThrowableEx& t, const except::Context& c) : _Base(t, c){} \
       CODA_OSS_except_Exception_suppress_26447_BEGIN_ \
       std::string getType() const noexcept override { return #_Name #Exception_; } \
-      CODA_OSS_except_Exception_suppress_26447_END_ };
+      CODA_OSS_except_Exception_suppress_26447_END_ }
 #define DECLARE_EXTENDED_EXCEPTION(_Name, _Base) DECLARE_EXTENDED_EXCEPTION_(_Name, Exception, _Base)
 #define DECLARE_EXTENDED_EXCEPTIONEX(_Name, _Base) DECLARE_EXTENDED_EXCEPTION_(_Name, ExceptionEx, _Base)
 
diff --git a/modules/c++/except/include/except/Throwable.h b/modules/c++/except/include/except/Throwable.h
index 0f3427ed45..84fe4d0385 100644
--- a/modules/c++/except/include/except/Throwable.h
+++ b/modules/c++/except/include/except/Throwable.h
@@ -34,6 +34,7 @@
 
 #include "config/Exports.h"
 #include "config/compiler_extensions.h"
+#include "config/disable_compiler_warnings.h"
 #include "except/Trace.h"
 
 /* Determine whether except::Throwable derives from std::exception.
diff --git a/modules/c++/except/source/Backtrace.cpp b/modules/c++/except/source/Backtrace.cpp
index 3131668082..6b8e24a622 100644
--- a/modules/c++/except/source/Backtrace.cpp
+++ b/modules/c++/except/source/Backtrace.cpp
@@ -28,6 +28,8 @@
 #include <cstdlib>
 #include <sstream>
 
+#include "config/disable_compiler_warnings.h"
+
 #if !CODA_OSS_except_Backtrace
 
 static std::string getBacktrace_(bool& supported, std::vector<std::string>&)
diff --git a/modules/c++/hdf5.lite/include/hdf5/lite/SpanRC.h b/modules/c++/hdf5.lite/include/hdf5/lite/SpanRC.h
index 7d6582124d..9392890bb2 100644
--- a/modules/c++/hdf5.lite/include/hdf5/lite/SpanRC.h
+++ b/modules/c++/hdf5.lite/include/hdf5/lite/SpanRC.h
@@ -105,8 +105,8 @@ struct SpanRC final
     }
 
     private:
-    types::RowCol<size_t> rc_;
     coda_oss::span<T> s_;
+    types::RowCol<size_t> rc_;
 };
 
 }
diff --git a/modules/c++/hdf5.lite/unittests/test_hdf5write.cpp b/modules/c++/hdf5.lite/unittests/test_hdf5write.cpp
index 0d99d11050..2d0dde8502 100644
--- a/modules/c++/hdf5.lite/unittests/test_hdf5write.cpp
+++ b/modules/c++/hdf5.lite/unittests/test_hdf5write.cpp
@@ -47,6 +47,8 @@ TEST_CASE(test_hdf5Create)
 
     // https://www.mathworks.com/help/matlab/ref/h5write.html
     hdf5::lite::createFile<float>(path, "/DS1", {10, 20});
+
+    TEST_ASSERT_TRUE(true); // need to use hidden "testName" parameter
 }
 
 TEST_CASE(test_hdf5Write)
diff --git a/modules/c++/io/source/InputStream.cpp b/modules/c++/io/source/InputStream.cpp
index a6e8c01523..3fd81e2f6c 100644
--- a/modules/c++/io/source/InputStream.cpp
+++ b/modules/c++/io/source/InputStream.cpp
@@ -65,7 +65,9 @@ sys::SSize_T InputStream::streamTo(OutputStream& soi, sys::SSize_T bytesToPipe)
     sys::SSize_T bytesRead = 0;
     sys::SSize_T totalBytesTransferred = 0;
 
-    sys::SSize_T sizeOfVec = (bytesToPipe <= DEFAULT_CHUNK_SIZE) ? (bytesToPipe) : (DEFAULT_CHUNK_SIZE);
+    constexpr auto defaultChunkSize = static_cast<sys::SSize_T>(DEFAULT_CHUNK_SIZE);
+
+    sys::SSize_T sizeOfVec = (bytesToPipe <= defaultChunkSize) ? bytesToPipe : defaultChunkSize;
     sys::byte vec[DEFAULT_CHUNK_SIZE];
     memset(vec, 0, DEFAULT_CHUNK_SIZE);
 
@@ -79,8 +81,8 @@ sys::SSize_T InputStream::streamTo(OutputStream& soi, sys::SSize_T bytesToPipe)
         soi.write(vec, bytesRead);
         totalBytesTransferred += bytesRead;
         memset(vec, 0, DEFAULT_CHUNK_SIZE);
-        sizeOfVec = (bytesToPipe - totalBytesTransferred <= DEFAULT_CHUNK_SIZE) ?
-                    (bytesToPipe - totalBytesTransferred) : (DEFAULT_CHUNK_SIZE);
+        sizeOfVec = (bytesToPipe - totalBytesTransferred <= defaultChunkSize) ?
+                    (bytesToPipe - totalBytesTransferred) : defaultChunkSize;
     }
     // Return the number of bytes we piped
     return totalBytesTransferred;
diff --git a/modules/c++/logging/include/logging/Enums.h b/modules/c++/logging/include/logging/Enums.h
index 9dd89b63ef..95d7edeae7 100644
--- a/modules/c++/logging/include/logging/Enums.h
+++ b/modules/c++/logging/include/logging/Enums.h
@@ -40,7 +40,7 @@ namespace logging
  *
  *  Enumeration used to represent LogLevels
  */
-struct LogLevel
+struct LogLevel final
 {
     //! The enumerations allowed
     enum
@@ -124,7 +124,7 @@ struct LogLevel
     }
 
     //! destructor
-    ~LogLevel(){}
+    ~LogLevel() = default;
 
     //! Returns string representation of the value
     std::string toString() const
@@ -149,14 +149,10 @@ struct LogLevel
     }
 
     //! assignment operator
-    LogLevel& operator=(const LogLevel& o)
-    {
-        if (&o != this)
-        {
-            value = o.value;
-        }
-        return *this;
-    }
+    LogLevel& operator=(const LogLevel&) = default;
+    LogLevel(const LogLevel&) = default;
+    LogLevel& operator=(LogLevel&&) = default;
+    LogLevel(LogLevel&&) = default;
 
     bool operator==(const LogLevel& o) const { return value == o.value; }
     bool operator!=(const LogLevel& o) const { return value != o.value; }
diff --git a/modules/c++/logging/include/logging/LogRecord.h b/modules/c++/logging/include/logging/LogRecord.h
index 9423dc7468..df81ba04b8 100644
--- a/modules/c++/logging/include/logging/LogRecord.h
+++ b/modules/c++/logging/include/logging/LogRecord.h
@@ -50,7 +50,7 @@ class LogRecord
               std::string file, std::string function, int lineNum, std::string timestamp) :
             mName(name), mMsg(msg), mLevel(level), mFile(file), mFunction(function),
             mLineNum(lineNum), mTimestamp(timestamp){}
-    virtual ~LogRecord(){}
+    virtual ~LogRecord() = default;
 
     LogLevel getLevel() const { return mLevel; }
     std::string getLevelName() const;
diff --git a/modules/c++/logging/source/Setup.cpp b/modules/c++/logging/source/Setup.cpp
index 99cc8309a5..e1a7e6491e 100644
--- a/modules/c++/logging/source/Setup.cpp
+++ b/modules/c++/logging/source/Setup.cpp
@@ -19,6 +19,10 @@
  * see <http://www.gnu.org/licenses/>.
  *
  */
+#include "logging/Setup.h"
+
+#include <stdint.h>
+#include <limits>
  
 #include <str/Manip.h>
 
@@ -28,8 +32,6 @@
 #include "logging/StandardFormatter.h"
 #include "logging/XMLFormatter.h"
 
-#include "logging/Setup.h"
-
 std::unique_ptr<logging::Logger>
 logging::setupLogger(const std::filesystem::path& program_, 
                      const std::string& logLevel, 
@@ -69,9 +71,14 @@ logging::setupLogger(const std::filesystem::path& program_,
         logHandler.reset(new logging::StreamHandler());
     else
     {
+        // Existing code was checking whether a 'size_t' was <0; that of course can't
+        // ever happen because 'size_t' is an unsigned type.  But, in the spirit of 
+        // the existing code, assume that somebody thought such a check was meaningful
+        // ... using the value of a 32-bit integer (we now only build on 64-bit platforms).
+
         // create a rotating logger
-        logCount = (logCount < 0) ? 0 : logCount;
-        logBytes = (logBytes < 0) ? 0 : logBytes;
+        logCount = logCount > std::numeric_limits<uint32_t>::max() ? 0 : logCount; // logCount = (logCount < 0) ? 0 : logCount;
+        logBytes = logBytes > std::numeric_limits<uint32_t>::max() ? 0 : logBytes; // logBytes = (logBytes < 0) ? 0 : logBytes;
         if (logBytes > 0)
         {
             logHandler.reset(new logging::RotatingFileHandler(logFile,
diff --git a/modules/c++/logging/unittests/test_exception_logger.cpp b/modules/c++/logging/unittests/test_exception_logger.cpp
index 55250b3607..375b4b5f47 100644
--- a/modules/c++/logging/unittests/test_exception_logger.cpp
+++ b/modules/c++/logging/unittests/test_exception_logger.cpp
@@ -121,7 +121,8 @@ TEST_CASE(testExceptionWithBacktrace)
     }
     catch (const except::Throwable& t)
     {
-        TEST_ASSERT_GREATER(t.getBacktrace().size(), static_cast<size_t>(0));
+        const auto backtraceSize = static_cast<int64_t>(t.getBacktrace().size());
+        TEST_ASSERT_GREATER(backtraceSize, 0);
         s = t.toString(true /*includeBacktrace*/);
         what = t.what();
     }
diff --git a/modules/c++/math.linear/unittests/test_lin.cpp b/modules/c++/math.linear/unittests/test_lin.cpp
index 3dc706ea9e..cc46d74a5d 100644
--- a/modules/c++/math.linear/unittests/test_lin.cpp
+++ b/modules/c++/math.linear/unittests/test_lin.cpp
@@ -81,6 +81,7 @@ TEST_CASE(testSTLVectorAssign)
 TEST_CASE(testEmptyDim)
 {
     math::linear::Matrix2D<double> AScale(3, 0);
+    TEST_ASSERT_TRUE(true); // need to use hidden "testName" parameter
 }
 
 TEST_CASE(testPtrDecorator)
@@ -100,6 +101,7 @@ TEST_CASE(testPtrAdopt)
 {
     // valgrind to ensure that we don't have a leak
     math::linear::Matrix2D<double> AScale(3, 3, new double[9], true);
+    TEST_ASSERT_TRUE(true); // need to use hidden "testName" parameter
 }
 
 TEST_CASE(testArithmetic)
@@ -216,4 +218,4 @@ TEST_MAIN(
 
     std::cout << cross(v3, y) << std::endl;
 */
-)
\ No newline at end of file
+)
diff --git a/modules/c++/mt/unittests/Runnable1DTest.cpp b/modules/c++/mt/unittests/Runnable1DTest.cpp
index 61ad49ae8f..14a419d782 100644
--- a/modules/c++/mt/unittests/Runnable1DTest.cpp
+++ b/modules/c++/mt/unittests/Runnable1DTest.cpp
@@ -69,6 +69,7 @@ TEST_CASE(DoRunnable1DTest)
     const AddOp op;
     std::cout << "Calling run1D\n";
     mt::run1D(10, 16, op);
+    TEST_ASSERT_TRUE(true); // need to use hidden "testName" parameter
 }
 
 TEST_CASE(Runnable1DWithCopiesTest)
@@ -79,6 +80,7 @@ TEST_CASE(Runnable1DWithCopiesTest)
     const LocalStorage op;
     std::cout << "Calling run1D\n";
     mt::run1DWithCopies(47, 16, op);
+    TEST_ASSERT_TRUE(true); // need to use hidden "testName" parameter
 }
 
 TEST_CASE(transform_async_test)
diff --git a/modules/c++/net/include/net/URL.h b/modules/c++/net/include/net/URL.h
index 55fa55b52e..ea9b4f8fe7 100644
--- a/modules/c++/net/include/net/URL.h
+++ b/modules/c++/net/include/net/URL.h
@@ -46,7 +46,7 @@ class URLParams
     typedef std::list<std::string> ParamValues;
     typedef std::map<std::string, ParamValues> Params;
 
-    URLParams(const std::string paramString = "");
+    URLParams(std::string paramString = "");
 
     bool contains(std::string key) const;
     ParamValues& get(std::string key);
@@ -68,17 +68,18 @@ class URL
 {
 public:
 
-    URL(const std::string url = "");
+    URL(std::string url = "");
 
     /*!
      *  Copy constructor.
      *  \param url A right-hand-side URL
      */
-    URL(const URL& url);
+    URL(const URL&);
+    URL& operator=(const URL&);
+    URL(URL&&) = default;
+    URL& operator=(URL&&) = default;
 
-    virtual ~URL()
-    {
-    }
+    virtual ~URL() = default;
 
     void set(std::string url);
 
@@ -106,7 +107,7 @@ class URL
     friend class URLBuilder;
     std::string mProtocol;
     std::string mHost;
-    int mPort;
+    int mPort = -1;
     std::string mPath;
     URLParams mParams;
     std::string mFragment;
diff --git a/modules/c++/net/source/URL.cpp b/modules/c++/net/source/URL.cpp
index a14219f7e6..881a4b8547 100644
--- a/modules/c++/net/source/URL.cpp
+++ b/modules/c++/net/source/URL.cpp
@@ -24,21 +24,28 @@
 #include <import/str.h>
 #include <import/sys.h>
 
-net::URL::URL(const std::string url) :
-    mPort(-1)
+net::URL::URL(std::string url)
 {
     if (!url.empty())
         set(url);
 }
 
-net::URL::URL(const net::URL& url)
+net::URL& net::URL::operator=(const URL& url)
 {
+  if (this != &url)
+  {
     mProtocol = url.getProtocol();
     mHost = url.getHost();
     setPort(url.getPort());
     mPath = url.getPath();
     mFragment = url.getFragment();
     mParams = net::URLParams(url.getParams().toString());
+  }
+  return *this;
+}
+net::URL::URL(const URL& url)
+{
+    *this = url;
 }
 
 void net::URL::set(std::string url)
@@ -122,7 +129,7 @@ bool net::URL::operator==(const net::URL& url) const
     return toString() == url.toString();
 }
 
-net::URLParams::URLParams(const std::string paramString)
+net::URLParams::URLParams(std::string paramString)
 {
     if (!paramString.empty())
     {
diff --git a/modules/c++/str/unittests/test_base_convert.cpp b/modules/c++/str/unittests/test_base_convert.cpp
index 26ab0ece7b..358fa6827a 100644
--- a/modules/c++/str/unittests/test_base_convert.cpp
+++ b/modules/c++/str/unittests/test_base_convert.cpp
@@ -362,6 +362,8 @@ static void test_wide_(const std::string& testName, const char* pStr, std::u16st
     const std::string std_str(static_cast<const char*>(wide_str)); //  UTF-16 -> Windows-1252
     TEST_ASSERT_EQ(encoded.native(), std_str);
     TEST_ASSERT_EQ(std_str, pStr);
+    #else
+    pUtf16 = pUtf16; // avoid unused-parameter warning
     #endif
 }
 
@@ -436,6 +438,8 @@ TEST_CASE(test_Windows1252_WIN32)
     constexpr auto w1252_unassigned = "\x81\x8d\x8f\x90\x9d";
     constexpr auto u16_w1252_unassigned = u"\x81\x8d\x8f\x90\x9d";
     test_Windows1252_(testName, w1252_unassigned, u16_w1252_unassigned);
+    #else
+    TEST_ASSERT_TRUE(true); // need to use hidden "testName" parameter
     #endif
 }
 
@@ -613,4 +617,4 @@ TEST_MAIN(
     TEST_CHECK(test_Windows1252);
     TEST_CHECK(test_EncodedStringView);
     TEST_CHECK(test_EncodedString);
-    )
\ No newline at end of file
+    )
diff --git a/modules/c++/sys/include/sys/Conf.h b/modules/c++/sys/include/sys/Conf.h
index e910f51356..ad5a1e4c99 100644
--- a/modules/c++/sys/include/sys/Conf.h
+++ b/modules/c++/sys/include/sys/Conf.h
@@ -38,9 +38,21 @@
 #ifndef _WIN32
 #include <features.h>
 #endif
-#define CODA_OSS_POSIX_SOURCE (defined(_POSIX_C_SOURCE) && (_POSIX_C_SOURCE >= 1))
-#define CODA_OSS_POSIX2001_SOURCE CODA_OSS_POSIX_SOURCE && (_POSIX_C_SOURCE >= 200112L)
-#define CODA_OSS_POSIX2008_SOURCE CODA_OSS_POSIX2001_SOURCE && (_POSIX_C_SOURCE >= 200809L)
+
+#undef CODA_OSS_POSIX_SOURCE
+#if defined(_POSIX_C_SOURCE) && (_POSIX_C_SOURCE >= 1)
+#define CODA_OSS_POSIX_SOURCE _POSIX_C_SOURCE
+#endif
+
+#undef CODA_OSS_POSIX2001_SOURCE
+#if defined(CODA_OSS_POSIX_SOURCE) && (_POSIX_C_SOURCE >= 200112L)
+#define CODA_OSS_POSIX2001_SOURCE _POSIX_C_SOURCE
+#endif
+
+#undef CODA_OSS_POSIX2008_SOURCE
+#if defined(CODA_OSS_POSIX2001_SOURCE) && (_POSIX_C_SOURCE >= 200809L)
+#define CODA_OSS_POSIX2008_SOURCE _POSIX_C_SOURCE
+#endif
 
 #include <config/Version.h>
 #include <config/Exports.h>
@@ -312,13 +324,13 @@ namespace sys
         void* p = nullptr;
 #ifdef _WIN32
         p = _aligned_malloc(size, alignment);
-#elif CODA_OSS_POSIX2001_SOURCE
+#elif defined(CODA_OSS_POSIX2001_SOURCE)
         // https://linux.die.net/man/3/posix_memalign
         if (posix_memalign(&p, alignment, size) != 0)
         {
             p = nullptr;
         }
-#elif CODA_OSS_POSIX_SOURCE
+#elif defined(CODA_OSS_POSIX_SOURCE)
         // https://linux.die.net/man/3/posix_memalign
         // "The functions memalign(), ... have been available in all Linux libc libraries."
         p = memalign(alignment, size);
diff --git a/modules/c++/sys/include/sys/DateTime.h b/modules/c++/sys/include/sys/DateTime.h
index 38b7424a77..5ca7db4459 100644
--- a/modules/c++/sys/include/sys/DateTime.h
+++ b/modules/c++/sys/include/sys/DateTime.h
@@ -31,6 +31,7 @@
 #include <string>
 
 #include "config/Exports.h"
+#include "config/disable_compiler_warnings.h"
 
 namespace sys
 {
diff --git a/modules/c++/sys/include/sys/Dbg.h b/modules/c++/sys/include/sys/Dbg.h
index 90d87546ed..96bfb098f0 100644
--- a/modules/c++/sys/include/sys/Dbg.h
+++ b/modules/c++/sys/include/sys/Dbg.h
@@ -27,6 +27,7 @@
 #pragma once
 
 #include "config/Exports.h"
+#include "config/disable_compiler_warnings.h"
 
 // A "debug" build has debugging symbols, detailed call stacks, minimal optimization, STL validation, etc.
 // A "release" build is likely to "run fast" and be "shipped;" it might lack much of what is in a "debug" build.
diff --git a/modules/c++/sys/include/sys/OS.h b/modules/c++/sys/include/sys/OS.h
index d126d7d674..6ea40c83fb 100644
--- a/modules/c++/sys/include/sys/OS.h
+++ b/modules/c++/sys/include/sys/OS.h
@@ -54,7 +54,7 @@ namespace sys
 		//MacOS
 	};
 
-	#if _WIN32
+	#ifdef _WIN32
 	constexpr auto Platform = PlatformType::Windows;
 	#else
     constexpr auto Platform = PlatformType::Linux;
diff --git a/modules/c++/sys/unittests/test_NaN_testing.cpp b/modules/c++/sys/unittests/test_NaN_testing.cpp
index b651af471c..82df405095 100644
--- a/modules/c++/sys/unittests/test_NaN_testing.cpp
+++ b/modules/c++/sys/unittests/test_NaN_testing.cpp
@@ -47,6 +47,7 @@ TEST_CASE(testNaNIsNotAlmostEqualToNumber)
     TEST_ASSERT_ALMOST_EQ_EPS(std::numeric_limits<float>::quiet_NaN(),
                 5, 3);
     */
+    TEST_ASSERT_TRUE(true); // need to use hidden "testName" parameter
 }
 
 TEST_CASE(testIsNaN)
diff --git a/modules/c++/sys/unittests/test_os.cpp b/modules/c++/sys/unittests/test_os.cpp
index 278a67f8a6..d4265494bc 100644
--- a/modules/c++/sys/unittests/test_os.cpp
+++ b/modules/c++/sys/unittests/test_os.cpp
@@ -162,7 +162,7 @@ TEST_CASE(testSplitEnv)
     std::vector<std::string> paths;
     bool result = os.splitEnv(pathEnvVar, paths);
     TEST_ASSERT_TRUE(result);
-    TEST_ASSERT_GREATER(paths.size(), static_cast<size_t>(0));
+    TEST_ASSERT_FALSE(paths.empty());
     for (const auto& path : paths)
     {
         TEST_ASSERT_TRUE(std::filesystem::exists(path));
@@ -183,7 +183,7 @@ TEST_CASE(testSplitEnv)
     paths.clear();
     result = os.splitEnv(pathEnvVar, paths, std::filesystem::file_type::directory);
     TEST_ASSERT_TRUE(result);
-    TEST_ASSERT_GREATER(paths.size(), static_cast<size_t>(0));
+    TEST_ASSERT_FALSE(paths.empty());
     paths.clear();
     result = os.splitEnv(pathEnvVar, paths, std::filesystem::file_type::regular);
     TEST_ASSERT_FALSE(result);
@@ -389,14 +389,14 @@ TEST_CASE(testFsFileSize)
     const sys::OS os;
     {
         const std::filesystem::path argv0(os.getSpecialEnv("ARGV0"));
-        const auto size = file_size(argv0);
-        TEST_ASSERT_GREATER(size, static_cast<size_t>(0));
+	const int64_t size = static_cast<int64_t>(file_size(argv0));
+        TEST_ASSERT_GREATER(size, 0);
     }
     {
         // We always have  sys::filesystem, even if it's not used.
         const sys::filesystem::path argv0(os.getSpecialEnv("ARGV0"));
-        const auto size = file_size(argv0);
-        TEST_ASSERT_GREATER(size, static_cast<size_t>(0));
+        const int64_t size = static_cast<int64_t>(file_size(argv0));
+        TEST_ASSERT_GREATER(size, 0);
     }
 }
 
diff --git a/modules/c++/sys/unittests/test_path.cpp b/modules/c++/sys/unittests/test_path.cpp
index 42e79af8e3..ab838d0275 100644
--- a/modules/c++/sys/unittests/test_path.cpp
+++ b/modules/c++/sys/unittests/test_path.cpp
@@ -53,7 +53,7 @@ TEST_CASE(testPathMerge)
     std::vector<std::string> paths;
     const auto splitResult = os.splitEnv("PATH", paths);
     TEST_ASSERT_TRUE(splitResult);
-    TEST_ASSERT_GREATER(paths.size(), static_cast<size_t>(0));
+    TEST_ASSERT_FALSE(paths.empty());
 
     auto path = find_directory(paths);
     TEST_ASSERT_TRUE(coda_oss::filesystem::is_directory(path));
@@ -65,7 +65,7 @@ TEST_CASE(testPathMerge)
 
     bool isAbsolute;
     auto components = sys::Path::separate(path, isAbsolute);
-    TEST_ASSERT_GREATER(components.size(), static_cast<size_t>(0));
+    TEST_ASSERT_FALSE(components.empty());
     auto result = sys::Path::merge(components, isAbsolute);
     TEST_ASSERT_EQ(result, path);
     TEST_ASSERT_TRUE(coda_oss::filesystem::is_directory(result));
diff --git a/modules/c++/xml.lite/unittests/test_soapelements.cpp b/modules/c++/xml.lite/unittests/test_soapelements.cpp
index 21ecbfdd86..6be98e7d46 100644
--- a/modules/c++/xml.lite/unittests/test_soapelements.cpp
+++ b/modules/c++/xml.lite/unittests/test_soapelements.cpp
@@ -43,6 +43,7 @@ struct SOAP final : public xml::lite::Document
                                       std::string characterData = "") override {
         const xml::lite::QName asQName(uri, qname);
         xml::lite::Element*  elem = new SOAPBody(asQName);
+        elem->setCharacterData(characterData); // avoid unused parameter warning
         elem->setCharacterData(test_text);
         return elem;
     }
diff --git a/modules/c++/xml.lite/unittests/test_xmlparser.cpp b/modules/c++/xml.lite/unittests/test_xmlparser.cpp
index 994ea52d85..6a4ff8bf18 100644
--- a/modules/c++/xml.lite/unittests/test_xmlparser.cpp
+++ b/modules/c++/xml.lite/unittests/test_xmlparser.cpp
@@ -145,6 +145,7 @@ TEST_CASE(testXml_setCharacterData)
     xml::lite::MinidomParser xmlParser;
     auto& a = testXmlUtf8_(xmlParser);
     a.setCharacterData(utf8Text8);
+    TEST_ASSERT_TRUE(true); // need to use hidden "testName" parameter
 }
 
 static std::string testXmlPrint_(std::string& expected, const std::string& characterData)