From e7f13d05b873bc39c21ab6a1df1278a2ab152ac5 Mon Sep 17 00:00:00 2001
From: Nicolas Fauvet <n.fauvet@abc-arbitrage.com>
Date: Thu, 19 Jan 2017 11:18:37 +0100
Subject: [PATCH] make code c++98 compatible

---
 fmt/format.h  | 8 ++++++++
 fmt/ostream.h | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/fmt/format.h b/fmt/format.h
index 58b416be..dc291aab 100644
--- a/fmt/format.h
+++ b/fmt/format.h
@@ -267,6 +267,14 @@ typedef __int64          intmax_t;
      (FMT_GCC_VERSION >= 303 && FMT_HAS_GXX_CXX11))
 #endif
 
+// Checks if decltype v1.1 is supported
+// http://en.cppreference.com/w/cpp/compiler_support
+#define FMT_HAS_DECLTYPE_INCOMPLETE_RETURN_TYPES \
+    (FMT_HAS_FEATURE(cxx_decltype_incomplete_return_types) || \
+    (FMT_GCC_VERSION >= 408 && FMT_HAS_GXX_CXX11) || \
+    FMT_MSC_VER >= 1900 || \
+    FMT_ICC_VERSION >= 1200)
+
 #ifdef FMT_HEADER_ONLY
 // If header only do not use extern templates.
 # undef FMT_USE_EXTERN_TEMPLATES
diff --git a/fmt/ostream.h b/fmt/ostream.h
index 7559547d..d7a9a9e2 100644
--- a/fmt/ostream.h
+++ b/fmt/ostream.h
@@ -74,6 +74,7 @@ struct ConvertToIntImpl<T, true> {
 // Write the content of w to os.
 void write(std::ostream &os, Writer &w);
 
+#ifdef FMT_HAS_DECLTYPE_INCOMPLETE_RETURN_TYPES
 template<typename T>
 class is_streamable {
   template<typename U>
@@ -85,6 +86,7 @@ class is_streamable {
 public:
   static constexpr bool value = decltype(test<T>(0))::value;
 };
+#endif
 }  // namespace internal
 
 // Formats a value.
@@ -123,7 +125,9 @@ typename std::enable_if<
  BasicWriter<Char>&
 >::type
 operator<<(BasicWriter<Char> &writer, const T &value) {
+#ifdef FMT_HAS_DECLTYPE_INCOMPLETE_RETURN_TYPES
   static_assert(internal::is_streamable<T>::value, "T must be Streamable");
+#endif
 
   auto &buffer = writer.buffer();
   Char *start = &buffer[0] + buffer.size();