diff --git a/include/dds.hpp b/include/dds.hpp
index 9cc0f6a..91178d8 100644
--- a/include/dds.hpp
+++ b/include/dds.hpp
@@ -1,23 +1,23 @@
 #pragma once
 
-#if __cplusplus >= 201703L && defined(DDS_USE_STD_FILESYSTEM)
+#include "dds_formats.hpp"
+
+#if DDS_CPP_17 && defined(DDS_USE_STD_FILESYSTEM)
 #include <filesystem>
 namespace fs = std::filesystem;
 #endif
 
-#if __cplusplus >= 202002L
+#if DDS_CPP_20
 #include <concepts>
 #endif
 
 #include <fstream>
 #include <iostream>
 
-#include "dds_formats.hpp"
-
 namespace dds {
     // Not going to include <algorithm> just for std::max and std::min
     template <typename T>
-#if __cplusplus >= 202002L
+#if DDS_CPP_20
     requires std::is_arithmetic_v<T>
 #endif
     inline constexpr const T& max(const T& a, const T& b) {
@@ -25,7 +25,7 @@ namespace dds {
     }
 
     template <typename T>
-#if __cplusplus >= 202002L
+#if DDS_CPP_20
     requires std::is_arithmetic_v<T>
 #endif
     inline constexpr const T& min(const T& a, const T& b) {
@@ -294,7 +294,7 @@ namespace dds {
     }
 #endif // #ifdef VK_VERSION_1_0
 
-#if __cplusplus >= 201703L && defined(DDS_USE_STD_FILESYSTEM)
+#if DDS_CPP_17 && defined(DDS_USE_STD_FILESYSTEM)
     DDS_NO_DISCARD inline dds::ReadResult readFile(const fs::path& filepath, dds::Image* image) {
 #else
     DDS_NO_DISCARD inline dds::ReadResult readFile(const std::string& filepath, dds::Image* image) {
diff --git a/include/dds_formats.hpp b/include/dds_formats.hpp
index ac0faab..73d3272 100644
--- a/include/dds_formats.hpp
+++ b/include/dds_formats.hpp
@@ -7,15 +7,26 @@
     static_cast<uint32_t>(char1) | (static_cast<uint32_t>(char2) << 8) | (static_cast<uint32_t>(char3) << 16) |                            \
         (static_cast<uint32_t>(char4) << 24)
 
-#define UNDO_FOUR_CHARACTER_CODE(x, name)                                                                                                  \
-    std::string name;                                                                                                                      \
-    name.reserve(4);                                                                                                                       \
-    name.push_back(x >> 0);                                                                                                                \
-    name.push_back(x >> 8);                                                                                                                \
-    name.push_back(x >> 16);                                                                                                               \
-    name.push_back(x >> 24);
+#define UNDO_FOUR_CHARACTER_CODE(x, name)                                                                                            \
+    unsigned char name[4];                                                                                                           \
+    name[0] = x >> 0;                                                                                                                \
+    name[1] = x >> 8;                                                                                                                \
+    name[2] = x >> 16;                                                                                                               \
+    name[3] = x >> 24;
 
-#if __cplusplus >= 201703L
+#if __cplusplus >= 201703L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201703L)
+#define DDS_CPP_17 1
+#else
+#define DDS_CPP_17 0
+#endif
+
+#if __cplusplus >= 202002L || (defined(_MSVC_LANG) && _MSVC_LANG >= 202002L)
+#define DDS_CPP_20 1
+#else
+#define DDS_CPP_20 0
+#endif
+
+#if DDS_CPP_17
 #define DDS_NO_DISCARD [[nodiscard]]
 #else
 #define DDS_NO_DISCARD
@@ -153,7 +164,7 @@ enum DXGI_FORMAT {
 // clang-format on
 
 namespace dds {
-#if __cplusplus >= 202002L
+#if DDS_CPP_20
     template <typename T>
     using span = std::span<T>;
 #else
diff --git a/tests/test.cpp b/tests/test.cpp
index bbc5095..11d7fe0 100644
--- a/tests/test.cpp
+++ b/tests/test.cpp
@@ -3,6 +3,7 @@
 #include <span>
 
 #define DDS_USE_STD_FILESYSTEM 1
+#include <filesystem>
 #include <dds.hpp>
 
 TEST_CASE("Read DDS and write PPM") {