diff --git a/UnitTests/pch.h b/UnitTests/pch.h
index 63cd120af..2fc1d4d26 100644
--- a/UnitTests/pch.h
+++ b/UnitTests/pch.h
@@ -8,18 +8,18 @@
 #define SECURITY_WIN32
 #define _WINSOCKAPI_	// Prevent inclusion of winsock.h in windows.h
 
-#include <stdex/base64.h>
-#include <stdex/errno.h>
-#include <stdex/exception.h>
-#include <stdex/hex.h>
-#include <stdex/idrec.h>
-#include <stdex/interval.h>
-#include <stdex/mapping.h>
-#include <stdex/parser.h>
-#include <stdex/progress.h>
-#include <stdex/sal.h>
-#include <stdex/sgml.h>
-#include <stdex/string.h>
-#include <stdex/vector_queue.h>
+#include <stdex/base64.hpp>
+#include <stdex/errno.hpp>
+#include <stdex/exception.hpp>
+#include <stdex/hex.hpp>
+#include <stdex/idrec.hpp>
+#include <stdex/interval.hpp>
+#include <stdex/mapping.hpp>
+#include <stdex/parser.hpp>
+#include <stdex/progress.hpp>
+#include <stdex/sal.hpp>
+#include <stdex/sgml.hpp>
+#include <stdex/string.hpp>
+#include <stdex/vector_queue.hpp>
 
 #include <CppUnitTest.h>
diff --git a/include/stdex/base64.h b/include/stdex/base64.hpp
similarity index 99%
rename from include/stdex/base64.h
rename to include/stdex/base64.hpp
index 7a618471e..58e8b9089 100644
--- a/include/stdex/base64.h
+++ b/include/stdex/base64.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 #include <assert.h>
 #include <cstdint>
 #include <string>
diff --git a/include/stdex/errno.h b/include/stdex/errno.hpp
similarity index 98%
rename from include/stdex/errno.h
rename to include/stdex/errno.hpp
index 571be4a9b..5a895051f 100644
--- a/include/stdex/errno.h
+++ b/include/stdex/errno.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 #include <stdexcept>
 #include <cstring>
 
diff --git a/include/stdex/exception.h b/include/stdex/exception.hpp
similarity index 96%
rename from include/stdex/exception.h
rename to include/stdex/exception.hpp
index 1f487cac6..f775582d8 100644
--- a/include/stdex/exception.h
+++ b/include/stdex/exception.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 #include <exception>
 
 namespace stdex
diff --git a/include/stdex/hex.h b/include/stdex/hex.hpp
similarity index 99%
rename from include/stdex/hex.h
rename to include/stdex/hex.hpp
index a67241afa..d9a11a8fd 100644
--- a/include/stdex/hex.h
+++ b/include/stdex/hex.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 #include <assert.h>
 #include <cstdint>
 #include <string>
diff --git a/include/stdex/idrec.h b/include/stdex/idrec.hpp
similarity index 99%
rename from include/stdex/idrec.h
rename to include/stdex/idrec.hpp
index ddc655883..4373f78db 100644
--- a/include/stdex/idrec.h
+++ b/include/stdex/idrec.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 #include <ios>
 #include <istream>
 #include <ostream>
diff --git a/include/stdex/interval.h b/include/stdex/interval.hpp
similarity index 98%
rename from include/stdex/interval.h
rename to include/stdex/interval.hpp
index d764ed345..b65189362 100644
--- a/include/stdex/interval.h
+++ b/include/stdex/interval.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 
 namespace stdex
 {
diff --git a/include/stdex/mapping.h b/include/stdex/mapping.hpp
similarity index 97%
rename from include/stdex/mapping.h
rename to include/stdex/mapping.hpp
index 7c6f1f283..ed6622bc0 100644
--- a/include/stdex/mapping.h
+++ b/include/stdex/mapping.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 #include <vector>
 
 namespace stdex
diff --git a/include/stdex/memory.h b/include/stdex/memory.hpp
similarity index 100%
rename from include/stdex/memory.h
rename to include/stdex/memory.hpp
diff --git a/include/stdex/parser.h b/include/stdex/parser.hpp
similarity index 99%
rename from include/stdex/parser.h
rename to include/stdex/parser.hpp
index 9e7e888ca..d9f47efdb 100644
--- a/include/stdex/parser.h
+++ b/include/stdex/parser.hpp
@@ -5,11 +5,11 @@
 
 #pragma once
 
-#include "interval.h"
-#include "memory.h"
-#include "sal.h"
-#include "sgml.h"
-#include "string.h"
+#include "interval.hpp"
+#include "memory.hpp"
+#include "sal.hpp"
+#include "sgml.hpp"
+#include "string.hpp"
 #include <assert.h>
 #include <stdarg.h>
 #include <stdint.h>
diff --git a/include/stdex/progress.h b/include/stdex/progress.hpp
similarity index 99%
rename from include/stdex/progress.h
rename to include/stdex/progress.hpp
index c52004a46..6fd07b349 100644
--- a/include/stdex/progress.h
+++ b/include/stdex/progress.hpp
@@ -5,8 +5,8 @@
 
 #pragma once
 
-#include "sal.h"
-#include "interval.h"
+#include "sal.hpp"
+#include "interval.hpp"
 #include <chrono>
 
 namespace stdex
diff --git a/include/stdex/sal.h b/include/stdex/sal.hpp
similarity index 100%
rename from include/stdex/sal.h
rename to include/stdex/sal.hpp
diff --git a/include/stdex/sgml.h b/include/stdex/sgml.hpp
similarity index 99%
rename from include/stdex/sgml.h
rename to include/stdex/sgml.hpp
index 121b341a7..8e2c727fc 100644
--- a/include/stdex/sgml.h
+++ b/include/stdex/sgml.hpp
@@ -5,10 +5,10 @@
 
 #pragma once
 
-#include "mapping.h"
-#include "sal.h"
-#include "sgml_unicode.h"
-#include "string.h"
+#include "mapping.hpp"
+#include "sal.hpp"
+#include "sgml_unicode.hpp"
+#include "string.hpp"
 #include <assert.h>
 
 namespace stdex
diff --git a/include/stdex/sgml_unicode.h b/include/stdex/sgml_unicode.hpp
similarity index 100%
rename from include/stdex/sgml_unicode.h
rename to include/stdex/sgml_unicode.hpp
diff --git a/include/stdex/string.h b/include/stdex/string.hpp
similarity index 99%
rename from include/stdex/string.h
rename to include/stdex/string.hpp
index 85d77a61a..039d95a39 100644
--- a/include/stdex/string.h
+++ b/include/stdex/string.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 #include <assert.h>
 #include <ctype.h>
 #include <stdint.h>
diff --git a/include/stdex/vector_queue.h b/include/stdex/vector_queue.hpp
similarity index 99%
rename from include/stdex/vector_queue.h
rename to include/stdex/vector_queue.hpp
index 8f8a22ba9..0d7d99e92 100644
--- a/include/stdex/vector_queue.h
+++ b/include/stdex/vector_queue.hpp
@@ -5,7 +5,7 @@
 
 #pragma once
 
-#include "sal.h"
+#include "sal.hpp"
 
 namespace stdex
 {