trying to use 17

fceller · fceller · commit 65a514c34472 · 2018-10-15T18:58:31.000+02:00
diff --git a/VERSIONS b/VERSIONS
@@ -1,3 +1,4 @@
+CXX_STANDARD "17"
 STARTER_REV "0.13.2"
 SYNCER_REV "0.5.3"
 GSEARCH_ID_HTTP     "010085642145132923492:fixi4yzeiz8"
diff --git a/lib/Futures/backports.h b/lib/Futures/backports.h
@@ -23,6 +23,11 @@
 #ifndef ARANGOD_FUTURES_BACKPORTS_H
 #define ARANGOD_FUTURES_BACKPORTS_H 1
 
+#if __cplusplus >= 201703L
+#include <type_traits>
+#include <utility>
+#endif
+
 namespace arangodb {
 namespace futures {
 
@@ -69,13 +74,19 @@ constexpr auto invoke(M(C::*d), Args&&... args)
 }
   
 #else
-#include <type_traits>
-#include <utility>
 using in_place_t = std::in_place_t;
-using in_place = std::in_place;
-using is_invocable = std::is_invocable;
-using is_invocable_r = std::is_invocable_r;
-using invoke = std::invoke;
+inline constexpr in_place_t in_place{};
+
+template <class R, class FN, class... ArgTypes>
+using is_invocable_r = std::is_invocable_r<R, FN, ArgTypes...>;
+
+template <class FN, class... ArgTypes>
+using is_invocable = std::is_invocable<FN, ArgTypes...>;
+
+template< class F, class... Args>
+auto invoke(F&& f, Args&&... args) noexcept -> decltype(std::invoke(f, args...)) {
+  return std::invoke(f, args...);
+}
 #endif
 
 }}
