From c947afdbae1061e07e0b16afa43534fc0cd7141c Mon Sep 17 00:00:00 2001
From: neargye <neargye@gmail.com>
Date: Wed, 2 Oct 2019 15:28:53 +0500
Subject: [PATCH] change check support compiler

---
 example/example.cpp    |  6 +++---
 include/magic_enum.hpp | 42 ++++++++++++++++++++++--------------------
 2 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/example/example.cpp b/example/example.cpp
index ee00b1e..3f5a72e 100644
--- a/example/example.cpp
+++ b/example/example.cpp
@@ -33,7 +33,7 @@ int main() {
   std::cout << c1_name << std::endl; // RED
 
   // String enum name sequence.
-  constexpr auto& color_names = magic_enum::enum_names<Color>();
+  constexpr auto color_names = magic_enum::enum_names<Color>();
   std::cout << "Color names:";
   for (auto n : color_names) {
     std::cout << " " << n;
@@ -70,7 +70,7 @@ int main() {
   std::cout << "Color[0] = " << magic_enum::enum_value<Color>(0) << std::endl; // Color[0] = RED
 
   // Enum value sequence.
-  constexpr auto& colors = magic_enum::enum_values<Color>();
+  constexpr auto colors = magic_enum::enum_values<Color>();
   std::cout << "Colors sequence:";
   for (Color c : colors) {
     std::cout << " " << c; // ostream operator for enum.
@@ -106,7 +106,7 @@ int main() {
   // Enum pair (value enum, string enum name) sequence.
   constexpr auto color_entries = magic_enum::enum_entries<Color>();
   std::cout << "Colors entries:";
-  for (auto& e : color_entries) {
+  for (auto e : color_entries) {
     std::cout << " "  << e.second << " = " << static_cast<int>(e.first);
   }
   std::cout << std::endl;
diff --git a/include/magic_enum.hpp b/include/magic_enum.hpp
index 481498d..5907f98 100644
--- a/include/magic_enum.hpp
+++ b/include/magic_enum.hpp
@@ -56,6 +56,10 @@
 
 namespace magic_enum {
 
+#if defined(__clang__) || defined(__GNUC__) && __GNUC__>= 9 || defined(_MSC_VER)
+#  define MAGIC_ENUM_SUPPORTED 1
+#endif
+
 // Enum value must be in range [MAGIC_ENUM_RANGE_MIN, MAGIC_ENUM_RANGE_MAX]. By default MAGIC_ENUM_RANGE_MIN = -128, MAGIC_ENUM_RANGE_MAX = 128.
 // If need another range for all enum types by default, redefine the macro MAGIC_ENUM_RANGE_MIN and MAGIC_ENUM_RANGE_MAX.
 // If need another range for specific enum type, add specialization enum_range for necessary enum type.
@@ -79,7 +83,7 @@ namespace detail {
 
 template <typename T>
 struct supported final
-#if defined(__clang__) || defined(__GNUC__) && __GNUC__>= 9 || defined(_MSC_VER) || defined(MAGIC_ENUM_NO_CHECK_SUPPORT)
+#if defined(MAGIC_ENUM_SUPPORTED) && MAGIC_ENUM_SUPPORTED
     : std::true_type {};
 #else
     : std::false_type {};
@@ -139,20 +143,19 @@ constexpr std::string_view pretty_name(std::string_view name) noexcept {
 template <typename E>
 constexpr auto n() noexcept {
   static_assert(is_enum_v<E>, "magic_enum::detail::n requires enum type.");
-#if defined(__clang__)
+#if defined(MAGIC_ENUM_SUPPORTED) && MAGIC_ENUM_SUPPORTED
+#  if defined(__clang__)
   constexpr std::string_view name{__PRETTY_FUNCTION__ + 34, sizeof(__PRETTY_FUNCTION__) - 36};
-#elif defined(__GNUC__)
+#  elif defined(__GNUC__)
   constexpr std::string_view name{__PRETTY_FUNCTION__ + 49, sizeof(__PRETTY_FUNCTION__) - 51};
-#elif defined(_MSC_VER)
+#  elif defined(_MSC_VER)
   constexpr std::string_view name{__FUNCSIG__ + 40, sizeof(__FUNCSIG__) - 57};
+#  endif
+  return static_string<name.size()>{name};
+#else
+  static_assert(supported<E>::value, "magic_enum: Unsupported compiler (https://github.com/Neargye/magic_enum#compiler-compatibility).");
+  return std::string_view{}; // Unsupported compiler.
 #endif
-
-  if constexpr (supported<E>::value) {
-    return static_string<name.size()>{name};
-  } else {
-    static_assert(supported<E>::value, "magic_enum: Unsupported compiler (https://github.com/Neargye/magic_enum#compiler-compatibility).");
-    return std::string_view{}; // Unsupported compiler.
-  }
 }
 
 template <typename E>
@@ -161,18 +164,17 @@ inline constexpr auto type_name_v = n<E>();
 template <typename E, E V>
 constexpr auto n() noexcept {
   static_assert(is_enum_v<E>, "magic_enum::detail::n requires enum type.");
-#if defined(__clang__) || defined(__GNUC__)
+#if defined(MAGIC_ENUM_SUPPORTED) && MAGIC_ENUM_SUPPORTED
+#  if defined(__clang__) || defined(__GNUC__)
   constexpr auto name = pretty_name({__PRETTY_FUNCTION__, sizeof(__PRETTY_FUNCTION__) - 2});
-#elif defined(_MSC_VER)
+#  elif defined(_MSC_VER)
   constexpr auto name = pretty_name({__FUNCSIG__, sizeof(__FUNCSIG__) - 17});
+#  endif
+  return static_string<name.size()>{name};
+#else
+  static_assert(supported<E>::value, "magic_enum: Unsupported compiler (https://github.com/Neargye/magic_enum#compiler-compatibility).");
+  return std::string_view{}; // Unsupported compiler.
 #endif
-
-  if constexpr (supported<E>::value) {
-    return static_string<name.size()>{name};
-  } else {
-    static_assert(supported<E>::value, "magic_enum: Unsupported compiler (https://github.com/Neargye/magic_enum#compiler-compatibility).");
-    return std::string_view{}; // Unsupported compiler.
-  }
 }
 
 template <typename E, E V>